Publications by authors named "Siraj Ali"

278 Publications

Structure-function analysis of oncogenic EGFR Kinase Domain Duplication reveals insights into activation and a potential approach for therapeutic targeting.

Nat Commun 2021 03 2;12(1):1382. Epub 2021 Mar 2.

Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.

Mechanistic understanding of oncogenic variants facilitates the development and optimization of treatment strategies. We recently identified in-frame, tandem duplication of EGFR exons 18 - 25, which causes EGFR Kinase Domain Duplication (EGFR-KDD). Here, we characterize the prevalence of ERBB family KDDs across multiple human cancers and evaluate the functional biochemistry of EGFR-KDD as it relates to pathogenesis and potential therapeutic intervention. We provide computational and experimental evidence that EGFR-KDD functions by forming asymmetric EGF-independent intra-molecular and EGF-dependent inter-molecular dimers. Time-resolved fluorescence microscopy and co-immunoprecipitation reveals EGFR-KDD can form ligand-dependent inter-molecular homo- and hetero-dimers/multimers. Furthermore, we show that inhibition of EGFR-KDD activity is maximally achieved by blocking both intra- and inter-molecular dimerization. Collectively, our findings define a previously unrecognized model of EGFR dimerization, providing important insights for the understanding of EGFR activation mechanisms and informing personalized treatment of patients with tumors harboring EGFR-KDD. Finally, we establish ERBB KDDs as recurrent oncogenic events in multiple cancers.
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http://dx.doi.org/10.1038/s41467-021-21613-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7925532PMC
March 2021

Optimized EGFR Blockade Strategies in Addicted Gastroesophageal Adenocarcinomas.

Clin Cancer Res 2021 Feb 4. Epub 2021 Feb 4.

Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Torino, Italy.

Purpose: Gastric and gastroesophageal adenocarcinomas represent the third leading cause of cancer mortality worldwide. Despite significant therapeutic improvement, the outcome of patients with advanced gastroesophageal adenocarcinoma is poor. Randomized clinical trials failed to show a significant survival benefit in molecularly unselected patients with advanced gastroesophageal adenocarcinoma treated with anti-EGFR agents.

Experimental Design: We performed analyses on four cohorts: IRCC (570 patients), Foundation Medicine, Inc. (9,397 patients), COG (214 patients), and the Fondazione IRCCS Istituto Nazionale dei Tumori (206 patients). Preclinical trials were conducted in patient-derived xenografts (PDX).

Results: The analysis of different gastroesophageal adenocarcinoma patient cohorts suggests that amplification drives aggressive behavior and poor prognosis. We also observed that EGFR inhibitors are active in patients with copy-number gain and that coamplification of other receptor tyrosine kinases or is associated with worse response. Preclinical trials performed on -amplified gastroesophageal adenocarcinoma PDX models revealed that the combination of an EGFR mAb and an EGFR tyrosine kinase inhibitor (TKI) was more effective than each monotherapy and resulted in a deeper and durable response. In a highly amplified nonresponding PDX, where resistance to EGFR drugs was due to inactivation of the tumor suppressor, cotreatment with the mTOR inhibitor everolimus restored sensitivity to EGFR inhibition.

Conclusions: This study underscores EGFR as a potential therapeutic target in gastric cancer and identifies the combination of an EGFR TKI and a mAb as an effective therapeutic approach. Finally, it recognizes mTOR pathway activation as a novel mechanism of primary resistance that can be overcome by the combination of EGFR and mTOR inhibitors.
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http://dx.doi.org/10.1158/1078-0432.CCR-20-0121DOI Listing
February 2021

Landscape of Cyclin Pathway Genomic Alterations Across 5,356 Prostate Cancers: Implications for Targeted Therapeutics.

Oncologist 2021 04 9;26(4):e715-e718. Epub 2021 Feb 9.

Center for Personalized Cancer Therapy and Division of Hematology and Oncology, University of California, San Diego, California, USA.

The cyclin pathway may confer resistance to standard treatments but also offer novel therapeutic opportunities in prostate cancer. Herein, we analyzed prostate cancer samples (majority metastatic) using comprehensive genomic profiling performed by next-generation sequencing (315 genes, >500× coverage) for alterations in activating and sensitizing cyclin genes (CDK4 amplification, CDK6 amplification, CCND1, CCND2, CCND3, CDKN2B [loss], CDKN2A [loss], SMARCB1), androgen receptor (AR) gene, and coalterations in genes leading to cyclin inhibitor therapeutic resistance (RB1 and CCNE1). Overall, cyclin sensitizing pathway genomic abnormalities were found in 9.7% of the 5,356 tumors. Frequent alterations included CCND1 amplification (4.2%) and CDKN2A and B loss (2.4% each). Alterations in possible resistance genes, RB1 and CCNE1, were detected in 9.7% (up to 54.6% in neuroendocrine) and 1.2% of cases, respectively, whereas AR alterations were seen in 20.9% of tumors (~27.3% in anaplastic). Cyclin sensitizing alterations were also more frequently associated with concomitant AR alterations.
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http://dx.doi.org/10.1002/onco.13694DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018295PMC
April 2021

Responsiveness to immune checkpoint inhibitors versus other systemic therapies in RET-aberrant malignancies.

ESMO Open 2020 10;5(5):e000799

Department of Investigational Cancer Therapeutics, UTMDACC, Houston, Texas, USA. Electronic address:

Purpose: The receptor tyrosine kinase rearranged during transfection (RET) can be oncogenically activated by gene fusions or point mutations. Multikinase inhibitors such as cabozantinib, lenvatinib and vandetanib have demonstrated activity in RET-dependent malignancies, and selective RET inhibitors (Selpercatinib and Pralsetinib) are in clinical trials. However, the responsiveness of RET-dependent malignancies to immune checkpoint inhibitors (ICIs) is unknown. We compared the time to treatment discontinuation (TTD) for ICI versus non-ICI therapy in patients with malignancies harbouring activating RET mutations or fusions (RET+).

Methods: A retrospective review of all RET+ patients who were referred to the phase I clinical trials programme at the University of Texas MD Anderson Cancer Center was conducted. TTD was estimated using Kaplan-Meier analysis. Multivariate analysis using the Cox proportional hazard model was performed to identify independent risk factors of treatment discontinuation.

Results: Of 70 patients who received systemic therapy for RET+ malignancies, 20 (28.6%) received ICI and 50 (71.4%) received non-ICI therapy. Non-ICI therapy was associated with decreased risk for treatment discontinuation compared with ICI in the overall population (HR=0.31; 95% CI 0.16-0.62; p=0.000834) and in patients with RET point mutations (HR=0.13; 95% CI 0.04-0.45; p=0.00134). In patients with RET fusions, non-ICI therapy was associated with a non-statistically significant decreased risk of treatment discontinuation (HR=0.59; 95% CI 0.25-1.4; p=0.24). ICI therapy and a diagnosis other than medullary thyroid cancer (MTC) were independent risk factors for treatment discontinuation.

Conclusion: Our study supports the prioritisation of non-ICI over ICI therapy in patients with RET+ tumours.
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http://dx.doi.org/10.1136/esmoopen-2020-000799DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7590373PMC
October 2020

Targetable gene fusions and aberrations in genitourinary oncology.

Nat Rev Urol 2020 Nov 12;17(11):613-625. Epub 2020 Oct 12.

Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

Gene fusions result from either structural chromosomal rearrangement or aberrations caused by splicing or transcriptional readthrough. The precise and distinctive presence of fusion genes in neoplastic tissues and their involvement in multiple pathways central to cancer development, growth and survival make them promising targets for personalized therapy. In genitourinary malignancies, rearrangements involving the E26 transformation-specific family of transcription factors have emerged as very frequent alterations in prostate cancer, especially the TMPRSS2-ERG fusion. In renal malignancies, Xp11 and t(6;11) translocations are hallmarks of a distinct pathological group of tumours described as microphthalmia-associated transcription factor family translocation-associated renal cell carcinomas. Novel druggable fusion events have been recognized in genitourinary malignancies, leading to the activation of several clinical trials. For instance, ALK-rearranged renal cell carcinomas have shown responses to alectinib and crizotinib. Erdafitinib has been tested for the treatment of FGFR-rearranged bladder cancer. Other anti-fibroblast growth factor receptor 3 (FGFR3) compounds are showing promising results in the treatment of bladder cancer, including infigratinib and pemigatinib, and all are currently in clinical trials.
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http://dx.doi.org/10.1038/s41585-020-00379-4DOI Listing
November 2020

Characterization of Clinical Cases of Malignant PEComa via Comprehensive Genomic Profiling of DNA and RNA.

Oncology 2020 23;98(12):905-912. Epub 2020 Sep 23.

Foundation Medicine, Cambridge, Massachusetts, USA,

Purpose: Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal soft tissue neoplasm often linked to mTOR pathway activation via TSC2 mutation. We analyzed a series of 31 consecutive metastatic PEComa (mPEComa) cases using a combined DNA/RNA hybrid capture-based comprehensive genomic profiling (CGP) assay to assess the genomic landscape of mPEComa.

Patients And Methods: Formalin-fixed, paraffin-embedded (FFPE) blocks or slides were obtained from tumors from 31 unique patients with mPEC-oma. DNA and RNA were extracted and CGP was performed on 405 genes using a targeted next-generation sequencing (NGS) assay in a CLIA-certified lab.

Results: All cases had locally advanced or metastatic disease, and 58% of patients were female with a median age of 50 years (range 8-76), and 17 and 14 specimens were from primary and metastatic sites, respectively. One hundred genomic alterations were identified in the cohort, with an average of 3.2 genomic alterations/case including alterations in TSC2 32.3% of cases (10), TSC1 9.6% (3), TFE3 16.1% (5, all fusions), and folliculin (FLCN) 6.4% (2), with all occurring in mutually exclusive fashion. Of TSC2 mutant cases, 70% had biallelic inactivation of this locus, as were 100% of TSC1 mutant cases. Two TSC1/2 wildtype cases harbored truncating mutations in FLCN, both of which were under LOH. Five TFE3 fusion cases were identified including the novel 5' fusion partner ZC3H4.

Conclusions: We describe for the first time mPEComa cases with FLCN mutations under LOH, further characterizing dysregulation of the mTOR pathway as a unifying theme in mPEC-oma. Cumulatively, we demonstrate the feasibility and potential utility of segregating mPEComa by TSC, TFE3, and FLCN status via CGP in clinical care.
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http://dx.doi.org/10.1159/000510241DOI Listing
December 2020

Prospective Decision Analysis Study of Clinical Genomic Testing in Metastatic Breast Cancer: Impact on Outcomes and Patient Perceptions.

JCO Precis Oncol 2019 18;3. Epub 2019 Nov 18.

The Ohio State University College of Medicine, Columbus, OH.

Purpose: To evaluate the impact of targeted DNA sequencing on selection of cancer therapy for patients with metastatic breast cancer (MBC).

Patients And Methods: In this prospective, single-center, single-arm trial, patients with MBC were enrolled within 10 weeks of starting a new therapy. At enrollment, tumor samples underwent next-generation sequencing for any of 315 cancer-related genes to high depth (> 500×) using FoundationOne CDx. Sequencing results were released to providers at the time of disease progression, and physician treatment recommendations were assessed via questionnaire. We evaluated three prespecified questions to assess patients' perceptions of genomic testing.

Results: In all, 100 patients underwent genomic testing, with a median of five mutations (range, 0 to 13 mutations) detected per patient. Genomic testing revealed one or more potential therapies in 98% of patients (98 of 100), and 60% of patients (60 of 100) had one or more recommended treatments with level I/II evidence for actionability. Among the 94 genomic text reports that were released, there was physician questionnaire data for 87 patients (response rate, 92.6%) and 31.0% of patients (27 of 87) had treatment change recommended by their physician. Of these, 37.0% (10 of 27) received the treatment supported by genomic testing. We did not detect a statistically significant difference in time-to-treatment failure (log-rank = .87) or overall survival ( = .71) among patients who had treatment change supported by genomic testing versus those who had no treatment change. For patients who completed surveys before and after genomic testing, there was a significant decrease in confidence of treatment success, specifically among patients who did not have treatment change supported by genomic testing (McNemar's test of agreement = .001).

Conclusion: In this prospective study, genomic profiling of tumors in patients with MBC frequently identified potential treatments and resulted in treatment change in a minority of patients. Patients whose therapy was not changed on the basis of genomic testing seemed to have a decrease in confidence of treatment success.
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http://dx.doi.org/10.1200/PO.19.00090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446448PMC
November 2019

Targetable BRAF and RAF1 Alterations in Advanced Pediatric Cancers.

Oncologist 2021 01 25;26(1):e153-e163. Epub 2020 Sep 25.

Foundation Medicine Inc., Morrisville, North, Carolina, USA.

RAF family protein kinases signal through the MAPK pathway to orchestrate cellular proliferation, survival, and transformation. Identifying BRAF alterations in pediatric cancers is critically important as therapeutic agents targeting BRAF or MEK may be incorporated into the clinical management of these patients. In this study, we performed comprehensive genomic profiling on 3,633 pediatric cancer samples and identified a cohort of 221 (6.1%) cases with known or novel alterations in BRAF or RAF1 detected in extracranial solid tumors, brain tumors, or hematological malignancies. Eighty percent (176/221) of these tumors had a known-activating short variant (98, 55.7%), fusion (72, 40.9%), or insertion/deletion (6, 3.4%). Among BRAF altered cancers, the most common tumor types were brain tumors (74.4%), solid tumors (10.8%), hematological malignancies (9.1%), sarcomas (3.4%), and extracranial embryonal tumors (2.3%). RAF1 fusions containing intact RAF1 kinase domain (encoded by exons 10-17) were identified in seven tumors, including two novel fusions TMF1-RAF1 and SOX6-RAF1. Additionally, we highlight a subset of patients with brain tumor with positive clinical response to BRAF inhibitors, demonstrating the rationale for incorporating precision medicine into pediatric oncology. IMPLICATIONS FOR PRACTICE: Precision medicine has not yet gained a strong foothold in pediatric cancers. This study describes the landscape of BRAF and RAF1 genomic alterations across a diverse spectrum of pediatric cancers, primarily brain tumors, but also encompassing melanoma, sarcoma, several types of hematologic malignancy, and others. Given the availability of multiple U.S. Food and Drug Administration-approved BRAF inhibitors, identification of these alterations may assist with treatment decision making, as described here in three cases of pediatric cancer.
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http://dx.doi.org/10.1002/ONCO.13519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794197PMC
January 2021

Pan-Cancer Analysis of and Genomic Alterations and Their Association With Genomic Instability as Measured by Genome-Wide Loss of Heterozygosity.

JCO Precis Oncol 2020 30;4:442-465. Epub 2020 Apr 30.

Foundation Medicine, Cambridge, MA.

Purpose: BRCA1 or BRCA2 loss of function results in homologous recombination deficiency (HRD), which is targetable by poly (ADP-ribose) polymerase (PARP) inhibitors and other DNA-damaging agents. In cancers associated with germline alterations (-associated cancers: breast, ovarian, pancreatic, prostate), alterations result in HRD and are biomarkers for PARP inhibitor use. In other (non--associated) cancer types, the association between alteration and HRD is less clear.

Methods: A total of 234,154 tumor samples were sequenced by hybrid capture-based comprehensive genomic profiling. Somatic, germline, and zygosity status was determined computationally. alterations were classified as predicted germline/somatic and biallelic/monoallelic. Genome-wide loss of heterozygosity (gLOH) was evaluated as a marker of HRD.

Results: alterations were observed at a 4.7% frequency. mutations were predicted germline in 57.4% of -associated and 37.2% of non--associated cancers. The fraction of -altered cases that were biallelic was 68.7%, with a higher biallelic fraction in -associated (89.9%) versus non--associated cancers (43.6%). Differences in tissue distribution of biallelic versus alterations were noted, including a higher rate of biallelic alteration in prostate cancer. Biallelic alteration was observed at a 3.2% frequency (-associated cancers, 8.9%; non--associated cancers, 1.3%) and > 1% frequency in at least 13 cancer types. Across cancer types, biallelic alteration was associated with increased gLOH versus monoallelic or wild-type ; predicted germline or somatic mutations were both associated with elevated gLOH.

Conclusion: Biallelic alterations were associated with elevated gLOH in diverse cancer types, including those not traditionally associated with cancer syndromes. Biomarker development for PARP inhibitors should integrate methods to distinguish biallelic from monoallelic status, and biallelic alteration should be broadly evaluated across cancer types as a biomarker for underlying HRD and PARP inhibitor sensitivity.
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http://dx.doi.org/10.1200/po.19.00345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446440PMC
April 2020

Cyclin Pathway Genomic Alterations Across 190,247 Solid Tumors: Leveraging Large-Scale Data to Inform Therapeutic Directions.

Oncologist 2021 01 15;26(1):e78-e89. Epub 2020 Sep 15.

Center for Personalized Cancer Therapy and Division of Hematology and Oncology, University of California, San Diego, California, USA.

Background: We describe the landscape of cyclin and interactive gene pathway alterations in 190,247 solid tumors.

Methods: Using comprehensive genomic profiling (315 genes, >500× coverage), samples were analyzed for alterations in activating/sensitizing cyclin genes (CDK4 amplification, CDK6 amplification, CCND1, CCND2, CCND3, CDKN2B [loss], CDKN2A [loss], SMARCB1), hormone genes (estrogen receptor 1 [ESR1], androgen receptor [AR]), and co-alterations in genes leading to cyclin inhibitor therapeutic resistance (RB1 and CCNE1).

Results: Alterations in at least one cyclin activating/sensitizing gene occurred in 24% of malignancies. Tumors that frequently harbored at least one cyclin alteration were brain gliomas (47.1%), esophageal (40.3%) and bladder cancer (37.9%), and mesotheliomas (37.9%). The most frequent alterations included CDKN2A (13.9%) and CDKN2B loss (12.5%). Examples of unique patterns of alterations included CCND1 amplification in breast cancer (17.3%); CDK4 alterations in sarcomas (12%); CCND2 in testicular cancer (23.4%), and SMARCB1 mutations in kidney cancer (3% overall, 90% in malignant rhabdoid tumors). Alterations in resistance genes RB1 and CCNE1 affected 7.2% and 3.6% of samples. Co-occurrence analysis demonstrated a lower likelihood of concomitant versus isolated alterations in cyclin activating/sensitizing and resistance genes (odds ratio [OR], 0.35; p < .001), except in colorectal, cervical, and small intestine cancers. AR and cyclin activating/sensitizing alterations in prostate cancer co-occurred more frequently (vs. AR alterations and wild-type cyclin activating/sensitizing alterations) (OR, 1.79; p < .001) as did ESR1 and cyclin activating/sensitizing alterations in breast (OR, 1.62; p < .001) and cervical cancer (OR, 4.08; p = .04) (vs. ESR1 and cyclin wild-type activating/sensitizing alterations).

Conclusion: Cyclin pathway alterations vary according to tumor type/histology, informing opportunities for targeted therapy, including for rare cancers.

Implications For Practice: Cyclin pathway genomic abnormalities are frequent in human solid tumors, with substantial variation according to tumor site and histology. Opportunities for targeted therapy emerge with comprehensive profiling of this pathway.
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http://dx.doi.org/10.1634/theoncologist.2020-0509DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794175PMC
January 2021

Comprehensive Genomic Profiling of Upper-tract and Bladder Urothelial Carcinoma.

Eur Urol Focus 2020 Aug 26. Epub 2020 Aug 26.

Foundation Medicine, Inc., Cambridge, MA, USA.

Background: Characterization of the different genomic alterations (GAs) in urothelial carcinoma (UC), by site of origin, may identify contrasting therapeutic opportunities and inform distinct putative pathogenetic mechanisms.

Objective: To describe the genomic landscape of UC based on the anatomic site of the primary tumor.

Design, Setting, And Participants: In total, 479 upper tract UC (UTUC) and 1984 bladder UC (BUC) patients underwent comprehensive genomic profiling (CGP) to evaluate all classes of GAs, tumor mutational burden (TMB), and microsatellite instability (MSI) status. Targetable GAs and signatures were assessed according to the European Society for Medical Oncology Scale for Clinical Actionability of molecular Targets (ESCAT).

Intervention: Hybrid-capture-based CGP.

Outcome Measurements And Statistical Analysis: Descriptive analyses and differences between anatomic subgroups were reported.

Results And Limitations: In total, 39% of patients with UC harbored one or more tier 1-2 GAs, suggesting potential benefit from approved or investigational therapies. UTUC cases were enriched in FGFR3 short variant (SV) GA (20% vs 13%) and HRAS SV GA (7.3% vs 3%), the latter attributed specifically to enrichment in renal pelvis UC (9.5%) versus ureteral UC (1.8%, p=0.002). RB1 GAs were more frequent in BUC than in UTUC (21% vs 7.8% p<0.001). Non-FGFR3 kinase fusions were observed in 1% of patients, including BRAF/RAF1 fusions in 0.5%. BRAF mutations/fusions were observed in 2% of cases and were mutually exclusive with FGFR3 GA (p=0.002). There were no differences of TMB high/MSI high for primary tumor and metastatic sites, but UTUC was enriched for MSI high (3.4%) relative to BUC (0.8%, p<0.001).

Conclusions: Differences in the genomic landscapes of UTUC and BUC were modest; however, patients with UTUC were enriched for FGFR3 and HRAS SV relative to BUC. Further investigation on UC, stratified by the site of origin, is warranted. In addition, these results suggest an opportunity for the routine incorporation of CGP prior to systemic therapy initiation in metastatic UC.

Patient Summary: Genomic profiling of advanced urothelial carcinoma can inform several therapeutic opportunities for patients, particularly those with upper tract urothelial carcinoma, an infrequent and generally aggressive tumor entity with nonoverlapping clinical features compared with its bladder counterpart, which is often treated based on the data extrapolated from bladder cancer.
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http://dx.doi.org/10.1016/j.euf.2020.08.001DOI Listing
August 2020

Retrospective analysis of real-world data to determine clinical outcomes of patients with advanced non-small cell lung cancer following cell-free circulating tumor DNA genomic profiling.

Lung Cancer 2020 10 6;148:69-78. Epub 2020 Aug 6.

Foundation Medicine, Cambridge, MA, USA.

Objectives: Liquid biopsy and comprehensive genomic profiling (CGP) of circulating tumor DNA (ctDNA) are increasingly used for detection of targetable genomic alterations (GA) in non-small cell lung cancer (NSCLC). To examine the clinical outcomes for patients following CGP using liquid biopsy versus tissue biopsy, receipt of matched targeted therapy post-CGP and associated outcomes were evaluated in the real-world setting.

Methods: 6491 patients with NSCLC and liquid biopsy (N = 937 tests) and/or tissue (N = 5582 tests) CGP were included in a de-identified commercial clinico-genomic database. Targetable GAs included National Comprehensive Cancer Network NSCLC guideline biomarkers. Clinical characteristics, real-world progression, and real-world response (rwR) were obtained via technology-enabled abstraction of clinician notes and radiology/pathology reports.

Results: At the time of liquid biopsy CGP, 53% (496/937) of patients were documented to have received ≥1 line of prior therapy (tissue CGP: 13%, 735/5582). 90% (832/928) of liquid biopsy cases had evidence of ctDNA. A targetable GA was detected in 20% (188/937) of liquid biopsy and 22% (1215/5582) of tissue CGP cases. Use of matched targeted therapy overall was similar post-liquid biopsy or post-tissue CGP but varied considerably across emerging (25%, 79/317) versus standard of care (SOC) (74%, 475/640) GA. Real-world-progression free survival for patients receiving SOC first line matched targeted therapy administered following liquid biopsy (n = 33) and tissue (n = 229) CGP were similar (13.8 vs 10.6 months; aHR = 0.68 [0.36-1.26]). Among patients evaluated for rwR, overall response rate (partial/complete response) to matched targeted therapy post-liquid biopsy CGP was 75% (39/52) versus 66% post-tissue CGP (254/385, P = 0.51).

Conclusion: Retrospective analysis of real-world clinico-genomic data demonstrated that clinical outcomes on matched targeted therapy were similar following liquid biopsy and tissue CGP in NSCLC, which suggests routine clinical use of liquid biopsy CGP can reliably guide therapy selection.
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http://dx.doi.org/10.1016/j.lungcan.2020.07.033DOI Listing
October 2020

Predicting the Pathologic Complete Response After Neoadjuvant Pembrolizumab in Muscle-Invasive Bladder Cancer.

J Natl Cancer Inst 2021 Jan;113(1):48-53

Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

Background: In the PURE-01 study (NCT02736266), we aimed to evaluate the ability to predict the pathologic complete response (pT0N0) after pembrolizumab by using clinical and tumor biomarkers.

Methods: In an open-label, single-arm, phase 2 study, 3 courses of 200 mg pembrolizumab preceding radical cystectomy were administered in patients with T2-4aN0M0 muscle-invasive bladder cancer. The analyses included a comprehensive genomic profiling and programmed cell-death-ligand-1 (PD-L1)-combined positive score assessment (CPS; Dako 22C3 antibody) of pre- and posttherapy samples. Multivariable logistic regression analyses evaluated baseline clinical T stage and tumor biomarkers in association with pT0N0 response. Corresponding coefficients were used to develop a calculator of pT0N0 response based on the tumor mutational burden (TMB), CPS, and the clinical T stage. Decision-curve analysis was also performed. All statistical tests were 2-sided.

Results: From February 2017 to June 2019, 112 patients with biomarker data were enrolled (105 with complete TMB and CPS data). Increasing TMB and CPS values featured a linear association with logistic pT0N0 probabilities (P = .02 and P = .004, respectively). For low TMB values (≤11 mut/Mb, median value, n = 53), pT0N0 probability was not associated with increasing CPS. Conversely, for high TMB values (>11 mut/Mb, n = 52), pT0N0 was statistically significantly associated with higher CPS (P = .004). The C index of the pT0N0 probability calculator was 0.77. On decision-curve analysis, the net benefit of the model was higher than the "treat-all" option within the clinically meaningful threshold probabilities of 40%-50%.

Conclusions: The study presents a composite biomarker-based pT0N0 probability calculator that reveals the complex interplay between TMB and CPS, added to the clinical T stage.
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http://dx.doi.org/10.1093/jnci/djaa076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7781448PMC
January 2021

Clinical and Genomic Characteristics of Small Cell Lung Cancer in Never Smokers: Results From a Retrospective Multicenter Cohort Study.

Chest 2020 10 26;158(4):1723-1733. Epub 2020 May 26.

Flatiron Health Inc, New York, NY.

Background: Small cell lung cancer (SCLC) has the strongest association with smoking among lung cancers. The characteristics of never smokers with SCLC is not known.

Research Question: Are the clinical characteristics, prognostic factors, survival, genomic alterations, and tumor mutational burdens of SCLC in patients who have never smoked different from those who have smoked?

Study Design And Methods: A retrospective multicenter cohort study of patients with clinician-confirmed SCLC was performed with the use of a longitudinal and nationally representative electronic medical records database. Smoking history was assessed through technology-enabled abstraction and confirmed for never smokers via chart review. Genomic characteristics of never smoker patients with SCLC were examined with the use of a next-generation sequencing-based gene panel and whole exome sequencing.

Results: One hundred of 5,632 patients (1.8%) with SCLC were never smokers. Relative to smokers, never smokers were more likely to be female (66.0% vs 52.4%; P = .009) and present with extensive stage (70.0% vs 62.2%; P = .028). Never smokers had a higher proportion of patients in age groups 35 to 49 years (7.0% vs 3.0%; P = .006) and ≥80 years (17.0% vs 8.2%; P = .006). Known risk factors for lung cancer were found in <20% of never smokers. There were no overall survival differences between never smokers and smokers. Among patients with available genomic data (n = 9), never smoker SCLC were characterized by lower tumor mutational burden, a lower frequency of TP53 mutations, and an absence of mutational signatures related to tobacco exposure.

Interpretation: The sex- and age-specific distribution of SCLC among never smokers, along with differences that were identified by genomic analyses, suggests a distinct biology of SCLC in never smokers compared with smokers.
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http://dx.doi.org/10.1016/j.chest.2020.04.068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7545488PMC
October 2020

Exceptional Response to Everolimus in a Patient with Metastatic Castrate-Resistant Prostate Cancer Harboring a PTEN Inactivating Mutation.

Case Rep Oncol 2020 Jan-Apr;13(1):456-461. Epub 2020 Apr 27.

Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.

Prostate cancer is among the most common types of cancer in men. Early detection and proper medical intervention is crucial to ensuring successful treatment. Here we describe a patient clinically presenting with castrate-resistant prostate carcinoma. Comprehensive genomic profiling identified a PTEN inactivating mutation in the patient's tumor. After being heavily pretreated, the patient showed stable disease on everolimus, a PI3K-Akt-mTOR pathway inhibitor.
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http://dx.doi.org/10.1159/000506625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204854PMC
April 2020

Recurrent secondary genomic alterations in desmoplastic small round cell tumors.

BMC Med Genet 2020 05 11;21(1):101. Epub 2020 May 11.

Foundation Medicine, Inc, Cambridge, MA, USA.

Background: Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive, translocation-associated soft-tissue sarcoma that primarily affects children, adolescents, and young adults, with a striking male predominance. It is characterized by t(11;22) generating a novel EWSR1-WT1 fusion gene. Secondary genomic alterations are rarely described.

Methods: Tumor tissue from 83 DSRCT patients was assayed by hybrid-capture based comprehensive genomic profiling, FoundationOne® Heme next generation sequencing analysis of 406 genes and RNA sequencing of 265 genes. Tumor mutation burden was calculated from a minimum of 1.4 Mb sequenced DNA. Microsatellite instability status was determined by a novel algorithm analyzing 114 specific loci.

Results: Comprehensive genomic profiling identified several genomically-defined DSRCT subgroups. Recurrent genomic alterations were most frequently detected in FGFR4, ARID1A, TP53, MSH3, and MLL3 genes. With the exception of FGFR4, where the genomic alterations predicted activation, most of the alterations in the remaining genes predicted gene inactivation. No DSRCT were TMB or MSI high.

Conclusions: In summary, recurrent secondary somatic alterations in FGFR4, ARID1A, TP53, MSH3, and MLL3 were detected in 82% of DSRCT, which is significantly greater than previously reported. These alterations may have both prognostic and therapeutic implications.
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http://dx.doi.org/10.1186/s12881-020-01034-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216377PMC
May 2020

Patients with NSCLCs Harboring Internal Inversions or Deletion Rearrangements of the Gene Have Durable Responses to ALK Kinase Inhibitors.

Lung Cancer (Auckl) 2020 17;11:33-39. Epub 2020 Apr 17.

Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA.

Background: fusions are targetable drivers in non-small-cell lung cancer (NSCLC). However, patients with NSCLC harboring rearrangements without a fusion partner identified in DNA have also been shown to respond to ALK inhibitors. We aimed to characterize complex variants that may predict sensitivity to multiple approved ALK inhibitors.

Methods: Comprehensive genomic profiling (CGP) of DNA isolated from formalin-fixed paraffin-embedded (FFPE) tumor tissue or blood-based circulating tumor DNA was performed for 39,159 NSCLC patients during routine clinical care. For a subset of cases, RNA sequencing was performed, and prior ALK test results and clinical treatment information were collected from treating physicians.

Results: We queried the Foundation Medicine NSCLC database and identified ALK internal inversions, as well as internal deletions, as the sole rearrangements in 6 (0.02%) and 3 (0.01%) of cases, respectively. In cases with internal inversions, RNA testing identified an fusion in 2/2 cases evaluated, and 3/3 patients treated with ALK inhibitors had durable responses. A single patient with an internal deletion and clinical data available responded to multiple ALK inhibitors. RNA data available for a subset of non-NSCLC cases suggest that internal deletions removing a portion of the N-terminus are drivers themselves and do not result in fusions. Fluorescence in situ hybridization (FISH) results were inconsistent for both classes of DNA events.

Conclusion: Rare internal inversions of appear to be indicative of fusions, which can be detected in RNA, and response to ALK inhibitors in patients with NSCLC. In contrast, internal deletions are not associated with fusions in RNA but likely represent targetable drivers themselves. These data suggest that CGP of DNA should be supplemented with immunohistochemistry or RNA-based testing to further resolve these events and match patients to effective therapies.
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http://dx.doi.org/10.2147/LCTT.S239675DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7184117PMC
April 2020

Genomic profiling of BCOR-rearranged uterine sarcomas reveals novel gene fusion partners, frequent CDK4 amplification and CDKN2A loss.

Gynecol Oncol 2020 05 7;157(2):357-366. Epub 2020 Mar 7.

Foundation Medicine Inc., Cambridge, MA, United States of America.

Objective: Genomic alterations of BCOR via ZC3H7B-BCOR fusion or BCOR internal tandem duplication (ITD) define a subset of endometrial stromal sarcoma (ESS). The goals of this study were to: 1) determine the molecular landscape of BCOR-rearranged ESS, 2) to identify novel BCOR fusion gene partners in ESS and their associated clinicopathological characteristics, and 3) to potentially unravel targetable genomic alterations in BCOR-mutated ESS.

Methods: A retrospective database search of a CLIA-certified molecular laboratory was performed for uterine sarcomas that contained BCOR rearrangements or BCOR ITD. The cases were previously assayed by comprehensive genomic profiling via both DNA- and RNA-based targeted next generation sequencing during the course of clinical care. Clinicopathological and genomic data was centrally re-reviewed.

Results: We identify largest cohort of BCOR-rearranged ESS to date (n = 40), which included 31 cases with canonical ZC3H7B-BCOR fusion as well as 8 cases with novel BCOR gene rearrangement partners, such as BCOR-L3MBTL2, EP300-BCOR, BCOR-NUTM2G, BCOR-RALGPS1, BCOR-MAP7D2, RGAG1-BCOR, ING3-BCOR, BCOR-NUGGC, KMT2D-BCOR, CREBBP-BCOR and 1 case with BCOR internal rearrangement. Re-review of cases with novel rearrangements demonstrated sarcomas with spindle, epithelioid or small round cell components and frequent myxoid stromal change. Comprehensive genomic profiling revealed high frequency of CDK4 and MDM2 amplification in 38% and 45% of BCOR-rearranged cases, respectively, and homozygous deletion of CDKN2A, which encodes an inhibitor of CDK4 in 28% of cases. Notably, CDK4 and MDM2 amplification was absent in all cases from 15 different ESS cases harboring BCOR ITD.

Conclusions: Alterations of CDK4 pathway members, for which targeted therapy is clinically available (i.e. palbociclib), via CDK4 amplification or CDKN2A loss, contributes to the pathogenesis of BCOR-rearranged uterine sarcomas, which may have therapeutic implications.
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http://dx.doi.org/10.1016/j.ygyno.2020.02.024DOI Listing
May 2020

Unfavorable Cancer-specific Survival After Neoadjuvant Chemotherapy and Radical Cystectomy in Patients With Bladder Cancer and Squamous Cell Variant: A Multi-institutional Study.

Clin Genitourin Cancer 2020 10 8;18(5):e543-e556. Epub 2020 Feb 8.

Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

Background: Nonurothelial carcinoma (UC) malignancies have traditionally been considered to have a more aggressive clinical course, and little is known about their response to neoadjuvant therapy. We examined the effect of neoadjuvant chemotherapy (NAC) on a large population of patients with bladder cancer (BCa) with different histologic variants (HVs).

Patients And Methods: We relied on a retrospective, multicenter database of 2858 patients with BCa who had undergone radical cystectomy with or without NAC from 1990 to 2017. Pure and mixed HVs were grouped into 6 categories: squamous cell carcinoma (SCC; n = 283; 45%), other subtypes (n = 95; 15%), micropapillary (n = 85; 14%), adenocarcinoma (n = 65; 10%), small cell (n = 54; 8.6%), and sarcomatous (n = 47; 7.6%). Kaplan-Meier and Cox regression analyses were used to examine cancer-specific survival (CSS) according to the HV, using pure UC as the reference. Logistic regression models were used to examine the odds of clinical-to-pathologic downstaging after NAC according to the HV.

Results: Overall, we identified 2229 cases of pure UC and 629 cases of BCa with HVs at radical cystectomy. Of the 450 NAC-treated patients, only those patients with SCC (n = 44; 9.8%) had had worse CSS (median CSS, 33 vs. 116 months; P < .001) and higher mortality rates (hazard ratio, 2.1; P = .03) compared with those with pure UC (n = 328; 72.9%). The results of the analyses were also confirmed when the pure and mixed cases were considered separately. After adjusting for NAC, only SCC showed a lower rate of clinical-to-pathologic downstaging (odds ratio, 0.4; P = .03) compared with UC.

Conclusions: SCC was the HV exhibiting the lowest effect of NAC in terms of activity and CSS. Compared with pure UC, SCC seemed to be insensitive to traditional NAC regimens.
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http://dx.doi.org/10.1016/j.clgc.2020.01.007DOI Listing
October 2020

Urothelial Cancers with Small Cell Variant Histology Have Confirmed High Tumor Mutational Burden, Frequent TP53 and RB Mutations, and a Unique Gene Expression Profile.

Eur Urol Oncol 2021 Apr 13;4(2):297-300. Epub 2020 Feb 13.

Foundation Medicine, Inc., Cambridge, MA, USA.

Although predominantly urothelial, some bladder cancer and upper tract urothelial cancer (BC/UTUC) harbor histologic variants. Small cell BC (SCBC) variants comprised ˜5% of The Cancer Genome Atlas BC cohort, with a poor prognosis. We describe genomic profiles of BC/UTUC with small cell/neuroendocrine features identified in the Foundation Medicine database from June 2012 to September 2018. Of 3368 BC/UTUC samples, 3.92% (132) harbored small cell/neuroendocrine features by immunohistochemistry. Mutations were noted in: TP53 (92%), RB1 (75%), combined TP53/RB1 (72%), and TERT promoter (68%). Of the samples, 6.5% had TMB ≥ 10 mutations/Mb. RNA expression profiling of 24 pure SCBC and 51 urothelial BC (UBC) muscle-invasive samples evaluated from a separate cohort revealed a large number of differentially expressed genes with suppression of several inflammatory pathways in SCBC compared with UBC. This largest reported SCBC dataset to date confirms enrichment of signatures in SCBC similar to small cell lung cancer and describes unique gene expression compared with UBC. These findings may explain aggressive SCBC phenotype. PATIENT SUMMARY: Small cell bladder cancer (SCBC) is an aggressive subtype that microscopically resembles aggressive small cell lung cancer (SCLC). This study confirms that SCBC shares DNA changes similar to SCLC and that SCBC expresses many genes that urothelial bladder cancer does not, possibly explaining aggressive SCBC activity.
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http://dx.doi.org/10.1016/j.euo.2019.12.002DOI Listing
April 2021

Clinicopathologic Characteristics of BRG1-Deficient NSCLC.

J Thorac Oncol 2020 05 24;15(5):766-776. Epub 2020 Jan 24.

Center for Integrated Diagnostics, Massachusetts General Hospital, Boston, Massachusetts. Electronic address:

Introduction: Ten percent of NSCLCs harbor mutations in SMARCA4, the gene encoding the SWItch/Sucrose Non-Fermentable ATPase BRG1. In preclinical models, BRG1 inactivation increases tumor aggressiveness but enhances sensitivity to drugs that target oxidative phosphorylation and inhibit SMARCA2, EZH2, CDK4, or CDK6. To facilitate translation of preclinical findings into clinical studies exploiting these therapeutic vulnerabilities, we assessed the clinical features of patients with tumors harboring BRG1-inactivating mutations.

Methods: Data sets from Massachusetts General Hospital and Foundation Medicine were reviewed to determine the prevalence of SMARCA4-mutant NSCLC and describe its clinicopathologic characteristics. BRG1 expression was evaluated by immunohistochemistry and correlated with SMARCA4 mutations. Treatment outcomes were retrospectively assessed.

Results: We detected SMARCA4 genomic alterations in 9% (n = 117 of 1422) and 11% (n = 3188 of 27,281) of NSCLCs in the institutional and Foundation Medicine data sets, respectively. In both cohorts, truncating mutations comprised over one-third of SMARCA4 alterations. Twenty-nine of 64 SMARCA4-mutant NSCLCs (45%) assessed for BRG1 expression reported loss of expression, most (90%) of which had truncating SMARCA4 mutations. Overall, 84% (n = 26 of 31) of evaluated NSCLCs with truncating SMARCA4 mutations lacked BRG1 expression. Deficient BRG1 expression was predominantly detected in adenocarcinomas with co-occurring mutations in KRAS, TP53, KEAP1, and STK11. Among patients with BRG1-deficient NSCLC who received first-line platinum doublet chemotherapy (n = 11) or chemotherapy plus immunotherapy (n = 5), median progression-free survival was 38 days and 35 days, respectively.

Conclusions: BRG1 deficiency is enriched in NSCLCs with truncating SMARCA4 mutations. Clinical outcomes are poor in this molecular subgroup, highlighting the importance of developing novel strategies to target unique vulnerabilities associated with the BRG1-deficient state.
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http://dx.doi.org/10.1016/j.jtho.2020.01.002DOI Listing
May 2020

Urothelial cancer harbours EGFR and HER2 amplifications and exon 20 insertions.

BJU Int 2020 05 23;125(5):739-746. Epub 2020 Feb 23.

Foundation Medicine, Cambridge, MA, USA.

Objective: To review the genomic landscape of advanced urothelial carcinoma (UC) to assess the frequencies of EGFR and ERBB2 (HER2) alterations.

Materials And Methods: Tumour specimens from 3753 patients with advanced UC were assayed with hybrid capture-based comprehensive genomic profiling of 180-395 genes. Tumour mutational burden (TMB) was assessed on 0.8 or 1.1 Mb of DNA, and is reported as mutations per megabase.

Results: In 3753 cases of UC, EGFR alterations were detected in 4.1% (154) and were most commonly amplifications (64%; 99/154), while exon 20 insertions (EGFR ) were the second most common alteration (18%; 27/154). Alterations in ERBB2 were observed in 15% (552/3753) of cases and, similarly, ERBB2 amplification was the most commonly observed alteration (278/552; 50%); ERBB2 occurred in 3.6% (20/552) of cases. EGFR and ERBB2 occurred in younger patients (median age 62 vs 69 years, P = 2.6E-2 and 60 vs 68 years, P = 7.8E-4), and these cases had significantly lower TMB (median 3.6 vs 7.2, P = 2.7E-4 and 2.5 vs 10, P = 1.2E-7) and less frequent TP53 alterations (3.7% vs 83%, P = 4.3E-14 and 20% vs 68%, P = 9.8E-4) compared to cases with other EGFR or ERBB2 alterations.

Conclusion: EGFR and ERBB2 alterations occur in 4% and 15% of UC, respectively. EGFR and ERBB2 were present in 0.7% and 0.5% of UC overall and collectively define a small, but distinct, subset of UC with infrequent co-occurrence of other drivers and low TMB. Given recent promising clinical studies of inhibitors with activity against exon 20 insertions in non-small cell lung cancer, consideration should be given to developing a trial inclusive of patients with UC harbouring these alterations.
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http://dx.doi.org/10.1111/bju.15006DOI Listing
May 2020

Comprehensive Assessment of Immuno-oncology Biomarkers in Adenocarcinoma, Urothelial Carcinoma, and Squamous-cell Carcinoma of the Bladder.

Eur Urol 2020 04 17;77(4):548-556. Epub 2020 Jan 17.

Foundation Medicine, Cambridge, MA, USA; Upstate Medical University, Syracuse, NY, USA.

Background: In patients with rare histologies of bladder cancer, including adenocarcinoma of the bladder (ACB) and squamous-cell carcinoma (SCC), there are limited standard therapy options, defining an unmet medical need.

Objective: In this comparative comprehensive genomic profiling (CGP) study, genomic alterations (GAs), and immuno-oncology (IO) biomarkers have been analyzed.

Design, Setting, And Participants: Within the Foundation Medicine database, 143 cases with centrally reviewed pure ACB, 2142 with pure urothelial carcinoma (UC), and 83 with pure SCC were subjected to CGP. All patients developed advanced disease following a primary diagnosis of bladder cancer.

Intervention: CGP using a hybrid capture-based assay and immunohistochemistry (IHC).

Outcome Measurements And Statistical Analysis: Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA, and microsatellite instability (MSI) was determined on 114 loci. Programmed cell-death ligand-1 (PD-L1) expression was determined by IHC (Ventana SP-142 assay), with >1% tumor cells (TCs) or tumor-infiltrating lymphocytes (TILs) scoring positive.

Results And Limitations: Pure ACB patients were younger and more often female than pure UC and pure SCC patients. UC and SCC had a significantly higher median TMB than ACB (p < 0.001). Rare CD274 (PD-L1) amplification cases were more frequently seen in SCC than in UC (5% vs 1%), and were not seen in ACB. MSI high status was very uncommon in all tumor types (0-1%). The frequencies of PD-L1 expression in both TCs and TILs was higher in UC and SCC (both 30%) than in ACB (18%). The results are limited by their retrospective nature and lack of clinical data annotation.

Conclusions: Deep sequencing revealed significant differences in IO biomarkers among the three major subtypes of bladder carcinomas. UC and SCC revealed higher frequencies of PD-L1 expression and higher TMB than ACB, and SCC has the highest frequency of CD274 amplification. The presence of pure SCC features should not disqualify patients for inclusion in IO trials.

Patient Summary: Tumor samples from patients diagnosed with advanced pure adenocarcinoma of the bladder (ACB) or pure squamous-cell carcinoma (SCC) have been analyzed in terms of frequency of putative immunotherapy biomarkers. The results indicated that pure SCC of the bladder was characterized by genomic features that portend similar response possibilities to immunotherapy compared with the classical pure urothelial carcinoma. Conversely, for pure ACB there might be different therapeutic opportunities, such as targeted therapies against peculiar genomic alterations in selected patients.
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http://dx.doi.org/10.1016/j.eururo.2020.01.003DOI Listing
April 2020

Squamous Transformation of Prostate Adenocarcinoma: A Report of Two Cases With Genomic Profiling.

Clin Genitourin Cancer 2020 06 4;18(3):e289-e292. Epub 2019 Dec 4.

Department of Medical Oncology and Experimental Therapeutics, City of Hope Comprehensive Cancer Center, Duarte, CA. Electronic address:

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http://dx.doi.org/10.1016/j.clgc.2019.11.020DOI Listing
June 2020

Multiparametric Magnetic Resonance Imaging as a Noninvasive Assessment of Tumor Response to Neoadjuvant Pembrolizumab in Muscle-invasive Bladder Cancer: Preliminary Findings from the PURE-01 Study.

Eur Urol 2020 05 25;77(5):636-643. Epub 2019 Dec 25.

Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy.

Background: In the PURE-01 study, pembrolizumab was given preoperatively before radical cystectomy in clinical T2-4aN0M0 patients. An accurate clinical response assessment may be useful for developing new perioperative strategies in these patients.

Objective: To evaluate the association between bladder multiparametric magnetic resonance imaging (mpMRI) findings after pembrolizumab and the pathological complete response (CR; pT0).

Design, Setting, And Participants: Patients were staged using bladder mpMRI whereby radiologists were asked to characterize the following parameters: residual disease at T1- and T2-weighted images (step 1: yes/no), presence of hyperintense spots within the bladder wall on diffusion-weighted imaging (step 2: yes/no), and presence of pathological contrast enhancement (step 3: yes/no), before and after three cycles of pembrolizumab. Examinations were internally assessed by two senior radiologists and externally evaluated by a third senior radiologist.

Intervention: To evaluate bladder tumor response after neoadjuvant pembrolizumab, mpMRI was used.

Outcome Measurements And Statistical Analysis: The primary objective was to predict the pT0 after neoadjuvant pembrolizumab by relying on the mpMRI findings. Cohen's kappa statistics was used to assess interobserver variability. Univariable analyses for pT0 were performed including internal and external post-therapy mpMRI steps.

Results And Limitations: From February 2017 to October 2018, 82 patients (164 total mpMRI assessments) were analyzed. The agreement between the internal and external mpMRI assessments after therapy was acceptable (κ values ranging from 0.5 to 0.76). Each mpMRI step was significantly associated with pT0 in both internal and external assessments. In patients with CR/no evidence of residual disease (NED) in all internally evaluated mpMRI steps (N = 37), the pT0 was seen in 23 (62%), compared with 19 of 26 externally evaluated NED patients (73%).

Conclusions: In post-pembrolizumab muscle-invasive bladder cancer, mpMRI sequence assessment had acceptable interobserver variability and represented the basis for the proposal of a radiological CR/NED status definition predicting the pT0 response to pembrolizumab. After validation of these findings with external datasets, we propose this tool for developing bladder-sparing immunotherapy maintenance therapies.

Patient Summary: Assessment of the extent of disease in patients with muscle-invasive bladder cancer using conventional imaging yields serious limitations. In the PURE-01 study, we evaluated the potential of bladder multiparametric magnetic resonance imaging (MRI) to predict the pathological complete response to neoadjuvant pembrolizumab. After validation with larger datasets, the proposed stepwise assessment incorporating multiparametric MRI sequences will be used at our center to develop bladder-sparing approaches in future studies.
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http://dx.doi.org/10.1016/j.eururo.2019.12.016DOI Listing
May 2020

Updated Results of PURE-01 with Preliminary Activity of Neoadjuvant Pembrolizumab in Patients with Muscle-invasive Bladder Carcinoma with Variant Histologies.

Eur Urol 2020 04 8;77(4):439-446. Epub 2019 Nov 8.

San Raffaele Hospital and Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.

Background: Patients with predominant variant histology (VH) of bladder tumors, defined as involving >50 % of the tumor specimens, are typically excluded from clinical trials, and for these patients, the efficacy of standard chemotherapy is limited.

Objective: To evaluate the activity of preoperative pembrolizumab in patients with muscle-invasive bladder carcinoma (MIBC) and VH, enrolled in PURE-01 study (NCT02736266).

Design, Setting, And Participants: In the open-label, single-arm, phase 2 PURE-01 study, three courses of 200 mg pembrolizumab preceding radical cystectomy (RC) were administered in T2-4aN0M0 MIBC patients. The amended study design included patients with predominant VH.

Intervention: Neoadjuvant pembrolizumab and RC.

Outcome Measurements And Statistical Analysis: Pathological complete response (pT0) in intention-to-treat population was the primary endpoint. Biomarker analyses included programmed cell-death ligand-1 (PD-L1) expression using the combined positive score (CPS; Dako 22C3 antibody) and comprehensive genomic profiling (FoundationOne assay). Multivariable logistic regression analyses (MVAs) evaluated the histological category (predominant VH vs nonpredominant VH vs pure urothelial carcinoma), tumor mutational burden (TMB) and CPS in association with the pathological response.

Results And Limitations: From February 2017 to June 2019, 114 patients were enrolled; 34 (30%) of them presented with VH, including 19 (17%) with predominant VH. In total, the pT0 rate was 37% (95% confidence interval [CI]: 28-46) and the pT ≤ 1 rate was 55% (95% CI: 46-65). The majority of predominant VH patients presented with squamous-cell carcinoma (SCC; N = 7), and six of seven (86%) had downstaging to pT ≤ 1, with one pT0; two of three lymphoepithelioma-like (LEL) variants had a pT0 response. None of the remaining nine predominant VHs had a response. On MVA, TMB and CPS were associated with both the pT0 and the pT ≤ 1 response, regardless of tumor histology.

Conclusions: The updated PURE-01 results confirm the activity of neoadjuvant pembrolizumab in MIBC. Patients with SCC and LEL features may be suitable for neoadjuvant immunotherapy trials. CPS and TMB are the key response predictors irrespective of the histological subtypes.

Patient Summary: In the PURE-01 study, we have preliminarily evaluated the activity of neoadjuvant pembrolizumab in patients with predominant variant histology (VH). Of these patients, those harboring squamous-cell carcinoma or a lymphoepithelioma-like variant feature had major, although preliminary, pathological responses compared with those with other predominant VHs. Expression of programmed cell-death ligand-1 and tumor mutational burden may predict the pathological response to pembrolizumab, and provide a rationale for selecting patients according to these features instead of the histological bladder cancer subtypes.
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http://dx.doi.org/10.1016/j.eururo.2019.10.026DOI Listing
April 2020

Novel rearrangement in multifocal infantile myofibromatosis is tumorigenic and sensitive to imatinib.

Cold Spring Harb Mol Case Stud 2019 10 23;5(5). Epub 2019 Oct 23.

Division of Hematology/Oncology, Departments of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.

Infantile myofibromatosis (IM) is an aggressive neoplasm composed of myofibroblast-like cells in children. Although typically localized, it can also present as multifocal disease, which represents a challenge for effective treatment. IM has previously been linked to activating somatic and germline point mutations in the PDGFRβ tyrosine kinase encoded by the gene. Clinical panel-based targeted tumor sequencing of a tumor from a newborn with multifocal IM revealed a novel rearrangement, which was reported as being of unclear significance. Additional sequencing of cDNA from tumor and germline DNA confirmed a complex somatic/mosaic rearrangement with an apparent partial tandem duplication disrupting the juxtamembrane domain. Ectopic expression of cDNA encoding the mutant form of PDGFRB markedly enhanced cell proliferation of mouse embryo fibroblasts (MEFs) compared to wild-type PDGFRB and conferred tumor-forming capacity on nontumorigenic 10T1/2 fibroblasts. The mutated protein enhanced MAPK activation and retained sensitivity to the PDGFRβ inhibitor imatinib. Our findings reveal a new mechanism by which PDGFRB can be activated in IM, suggest that therapy with tyrosine kinase inhibitors including imatinib may be beneficial, and raise the possibility that this receptor tyrosine kinase might be altered in a similar fashion in additional cases that would similarly present annotation challenges in clinical DNA sequencing analysis pipelines.
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http://dx.doi.org/10.1101/mcs.a004440DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6824247PMC
October 2019

TKI-resistant -rearranged lung adenocarcinoma with secondary CTNNB1 p.S45V and tertiary ALK p.I1171N mutations.

Lung Cancer (Auckl) 2019 15;10:81-86. Epub 2019 Aug 15.

Department of Pathology, Rhode Island Hospital and Alpert Medical School at Brown University, Providence, RI 02903, USA.

Anaplastic lymphoma kinase ()-rearranged non-small cell lung cancer (NSCLC) is an important molecular subgroup of tumors that are typically sensitive to tyrosine kinase inhibitors (TKIs). Although a substantial portion of patients benefit from TKIs, this approach is complicated by intrinsic and acquired resistance. We report a patient with -rearranged NSCLC who showed an initial response to targeted therapy, but developed resistance to multiple TKIs. Serial comprehensive genomic profiling (CGP) was performed at four independent points during the clinical course. We review the pathology and clonal progression of the tumor, with CGP identifying a secondary CTNNB1 p.S45V mutation after the initiation of targeted therapy, followed by tertiary ALK p.I1171N. The presence of an alteration in a second oncogenic driver gene suggests a possible mechanism for resistance, and a secondary therapeutic target. Due to the involvement of Wnt signaling in the pathogenesis of many tumors and its association with immune evasion, a variety of therapeutic strategies are being developed to target this pathway. This case exemplifies the challenges of targeted therapeutics in the face of tumor progression, as well as the increasing role of genomics in understanding tumor biology.
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http://dx.doi.org/10.2147/LCTT.S212406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699522PMC
August 2019

The Pan-Cancer Landscape of Coamplification of the Tyrosine Kinases KIT, KDR, and PDGFRA.

Oncologist 2020 01 11;25(1):e39-e47. Epub 2019 Oct 11.

Foundation Medicine, Inc., Cambridge, Massachusetts, USA.

Purpose: Amplifications of receptor tyrosine kinases (RTKS) are therapeutic targets in multiple tumor types (e.g. HER2 in breast cancer), and amplification of the chromosome 4 segment harboring the three RTKs KIT, PDGFRA, and KDR (4q12amp) may be similarly targetable. The presence of 4q12amp has been sporadically reported in small tumor specific series but a large-scale analysis is lacking. We assess the pan-cancer landscape of 4q12amp and provide early clinical support for the feasibility of targeting this amplicon.

Experimental Design: Tumor specimens from 132,872 patients with advanced cancer were assayed with hybrid capture based comprehensive genomic profiling which assays 186-315 genes for all classes of genomic alterations, including amplifications. Baseline demographic data were abstracted, and presence of 4q12amp was defined as 6 or more copies of KIT/KDR/PDGFRA. Concurrent alterations and treatment outcomes with matched therapies were explored in a subset of cases.

Results: Overall 0.65% of cases harbored 4q12amp at a median copy number of 10 (range 6-344). Among cancers with >100 cases in this series, glioblastomas, angiosarcomas, and osteosarcomas were enriched for 4q12amp at 4.7%, 4.8%, and 6.4%, respectively (all p < 0.001), giving an overall sarcoma (n = 6,885) incidence of 1.9%. Among 99 pulmonary adenocarcinoma cases harboring 4q12amp, 50 (50%) lacked any other known driver of NSLCC. Four index cases plus a previously reported case on treatment with empirical TKIs monotherapy had stable disease on average exceeding 20 months.

Conclusion: We define 4q12amp as a significant event across the pan-cancer landscape, comparable to known pan-cancer targets such as NTRK and microsatellite instability, with notable enrichment in several cancers such as osteosarcoma where standard treatment is limited. The responses to available TKIs observed in index cases strongly suggest 4q12amp is a druggable oncogenic target across cancers that warrants a focused drug development strategy.

Implications For Practice: Coamplification of the receptor tyrosine kinases (rtks) KIT/KDR/PDGFRA (4q12amp) is present broadly across cancers (0.65%), with enrichment in osteosarcoma and gliomas. Evidence for this amplicon having an oncogenic role is the mutual exclusivity of 4q12amp to other known drivers in 50% of pulmonary adenocarcinoma cases. Furthermore, preliminary clinical evidence for driver status comes from four index cases of patients empirically treated with commercially available tyrosine kinase inhibitors with activity against KIT/KDR/PDGFRA who had stable disease for 20 months on average. The sum of these lines of evidence suggests further clinical and preclinical investigation of 4q12amp is warranted as the possible basis for a pan-cancer drug development strategy.
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http://dx.doi.org/10.1634/theoncologist.2018-0528DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6964135PMC
January 2020

Genomic profiling of cell-free circulating tumor DNA in patients with colorectal cancer and its fidelity to the genomics of the tumor biopsy.

J Gastrointest Oncol 2019 Oct;10(5):831-840

Foundation Medicine, Cambridge, MA, USA.

Background: Liquid biopsy offers the ability to non-invasively analyze the genome of a tumor through circulating tumor DNA (ctDNA) to identify targetable and prognostic genomic alterations. Few studies have rigorously analyzed ctDNA results and determined the fidelity with which they recapitulate the genomics of a sequenced tissue sample obtained from the same tumor. The clinical utility study (CUS) for the FoundationACT™ ctDNA assay (Foundation Medicine, Cambridge, MA, USA; NCT02620527) is a multi-center prospective clinical study for multiple solid tumor types to compare genomic profiling of paired tissue and blood samples from the same patient. In this subset of the study, paired specimens from 96 patients with colorectal cancer (CRC) were analyzed with comprehensive genomic profiling (CGP) of the tumor tissue sample (FoundationOne) and blood sample (FoundationACT™).

Methods: Both samples underwent CGP using the hybrid capture-based Illumina Hi-Seq technology. Maximum somatic allele frequency (MSAF) was used to estimate the fraction of ctDNA in the sample. The set of genes and targeted regions common to both tumor and liquid were compared for each subject.

Results: Among these patients, 61% were male; 74% had clinical stage IV disease, 19% had clinical stage III disease, and 7% had clinical stage II disease. Time between the tissue biopsy and liquid biopsy (range, 0709 days) had a significant impact on the positive percent agreement (PPA) between the two assays. Eighty percent of cases had evidence of ctDNA in the blood (MSAF >0). For all cases with MSAF >0, 171 base substitutions and insertions/deletions (indels) were identified in the tumor, and 79% (PPA) of these identical alterations were also identified in matched ctDNA samples; PPA increased to 87% for cases <270 days between the tissue and liquid biopsy, 95% for <90 days, and 100% PPA for <30 days. All known and likely short variants in , and were analyzed independently as testing of these genes is recommended by the National Comprehensive Cancer Network (NCCN) for patients with CRC and have therapeutic implications. For NCCN genes, PPA was 80% for all time points for short variants; PPA increased to 90% for cases <270 days between the tissue and liquid biopsy. There was high concordance for G12X between tissue and liquid: overall percent agreement (97%), PPA (93%), negative percent agreement (NPA) (100%), positive predictive value (PPV) (100%), and negative predictive value (NPV) (96%) for the <270 day cohort.

Conclusions: In cases where tumor tissue profiling is not possible, these results provide compelling evidence that genomic profiling of ctDNA in late stage CRC shows a high concordance with tumor tissue sequencing results and can be used to identify most clinically relevant alterations capable of guiding therapy for these patients.
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http://dx.doi.org/10.21037/jgo.2019.05.05DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6776816PMC
October 2019