Publications by authors named "Peter W Laird"

164 Publications

Whole-genome characterization of lung adenocarcinomas lacking the RTK/RAS/RAF pathway.

Cell Rep 2021 02;34(5):108707

Fred Hutchinson Cancer Research Center, Seattle, WA, USA.

RTK/RAS/RAF pathway alterations (RPAs) are a hallmark of lung adenocarcinoma (LUAD). In this study, we use whole-genome sequencing (WGS) of 85 cases found to be RPA(-) by previous studies from The Cancer Genome Atlas (TCGA) to characterize the minority of LUADs lacking apparent alterations in this pathway. We show that WGS analysis uncovers RPA(+) in 28 (33%) of the 85 samples. Among the remaining 57 cases, we observe focal deletions targeting the promoter or transcription start site of STK11 (n = 7) or KEAP1 (n = 3), and promoter mutations associated with the increased expression of ILF2 (n = 6). We also identify complex structural variations associated with high-level copy number amplifications. Moreover, an enrichment of focal deletions is found in TP53 mutant cases. Our results indicate that RPA(-) cases demonstrate tumor suppressor deletions and genome instability, but lack unique or recurrent genetic lesions compensating for the lack of RPAs. Larger WGS studies of RPA(-) cases are required to understand this important LUAD subset.
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http://dx.doi.org/10.1016/j.celrep.2021.108707DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8009291PMC
February 2021

Molecular Features of Cancers Exhibiting Exceptional Responses to Treatment.

Cancer Cell 2021 01 19;39(1):38-53.e7. Epub 2020 Nov 19.

Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA.

A small fraction of cancer patients with advanced disease survive significantly longer than patients with clinically comparable tumors. Molecular mechanisms for exceptional responses to therapy have been identified by genomic analysis of tumor biopsies from individual patients. Here, we analyzed tumor biopsies from an unbiased cohort of 111 exceptional responder patients using multiple platforms to profile genetic and epigenetic aberrations as well as the tumor microenvironment. Integrative analysis uncovered plausible mechanisms for the therapeutic response in nearly a quarter of the patients. The mechanisms were assigned to four broad categories-DNA damage response, intracellular signaling, immune engagement, and genetic alterations characteristic of favorable prognosis-with many tumors falling into multiple categories. These analyses revealed synthetic lethal relationships that may be exploited therapeutically and rare genetic lesions that favor therapeutic success, while also providing a wealth of testable hypotheses regarding oncogenic mechanisms that may influence the response to cancer therapy.
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http://dx.doi.org/10.1016/j.ccell.2020.10.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8478080PMC
January 2021

Phase I trial of TRC102 (methoxyamine HCl) in combination with temozolomide in patients with relapsed solid tumors and lymphomas.

Oncotarget 2020 Nov 3;11(44):3959-3971. Epub 2020 Nov 3.

Early Clinical Trials Development Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.

Background: TRC102 inhibits base excision repair by binding abasic sites and preventing AP endonuclease processing; it potentiates the activity of alkylating agents, including temozolomide, in murine models. In published xenograft studies, TRC102 enhanced the antitumor effect of temozolomide regardless of cell line genetic characteristics, e.g., O6-methylguanine DNA methyltransferase (MGMT), mismatch repair (MMR), or p53 status.

Materials And Methods: We conducted a phase 1 trial of TRC102 with temozolomide given orally on days 1-5 of 28-day cycles in adult patients with refractory solid tumors that had progressed on standard therapy. Tumor induction of nuclear biomarkers of DNA damage response (DDR) γH2AX, pNBs1, and Rad51 was assessed in the context of MGMT and MMR protein expression for expansion cohort patients.

Results: Fifty-two patients were enrolled (37 escalation, 15 expansion) with 51 evaluable for response. The recommended phase 2 dose was 125 mg TRC102, 150 mg/m temozolomide QDx5. Common adverse events (grade 3/4) included anemia (19%), lymphopenia (12%), and neutropenia (10%). Four patients achieved partial responses (1 non-small cell lung cancer, 2 granulosa cell ovarian cancer, and 1 colon cancer) and 13 patients had a best response of stable disease. Retrospective analysis of 15 expansion cohort patients did not demonstrate a correlation between low tumor MGMT expression and patient response, but treatment induced nuclear Rad51 responses in 6 of 12 patients.

Conclusions: The combination of TRC 102 with temozolomide is active, with 4 of 51 patients experiencing a partial response and 13 of 51 experiencing stable disease, and the side effect profile is manageable.
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http://dx.doi.org/10.18632/oncotarget.27784DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7646836PMC
November 2020

Systematic Assessment of Tumor Purity and Its Clinical Implications.

JCO Precis Oncol 2020 4;4. Epub 2020 Sep 4.

Department of Human Genetics, University of California, Los Angeles, CA.

Purpose: The tumor microenvironment is complex, comprising heterogeneous cellular populations. As molecular profiles are frequently generated using bulk tissue sections, they represent an admixture of multiple cell types (including immune, stromal, and cancer cells) interacting with each other. Therefore, these molecular profiles are confounded by signals emanating from many cell types. Accurate assessment of residual cancer cell fraction is crucial for parameterization and interpretation of genomic analyses, as well as for accurately interpreting the clinical properties of the tumor.

Materials And Methods: To benchmark cancer cell fraction estimation methods, 10 estimators were applied to a clinical cohort of 333 patients with prostate cancer. These methods include gold-standard multiobserver pathology estimates, as well as estimates inferred from genome, epigenome, and transcriptome data. In addition, two methods based on genomic and transcriptomic profiles were used to quantify tumor purity in 4,497 tumors across 12 cancer types. Bulk mRNA and microRNA profiles were subject to in silico deconvolution to estimate cancer cell-specific mRNA and microRNA profiles.

Results: We present a systematic comparison of 10 tumor purity estimation methods on a cohort of 333 prostate tumors. We quantify variation among purity estimation methods and demonstrate how this influences interpretation of clinico-genomic analyses. Our data show poor concordance between pathologic and molecular purity estimates, necessitating caution when interpreting molecular results. Limited concordance between DNA- and mRNA-derived purity estimates remained a general pan-cancer phenomenon when tested in an additional 4,497 tumors spanning 12 cancer types.

Conclusion: The choice of tumor purity estimation method may have a profound impact on the interpretation of genomic assays. Taken together, these data highlight the need for improved assessment of tumor purity and quantitation of its influences on the molecular hallmarks of cancers.
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http://dx.doi.org/10.1200/PO.20.00016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7529507PMC
September 2020

Comprehensive Analysis of Genetic Ancestry and Its Molecular Correlates in Cancer.

Cancer Cell 2020 05;37(5):639-654.e6

The Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Harvard Medical School, Boston, MA 02115, USA; Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA. Electronic address:

We evaluated ancestry effects on mutation rates, DNA methylation, and mRNA and miRNA expression among 10,678 patients across 33 cancer types from The Cancer Genome Atlas. We demonstrated that cancer subtypes and ancestry-related technical artifacts are important confounders that have been insufficiently accounted for. Once accounted for, ancestry-associated differences spanned all molecular features and hundreds of genes. Biologically significant differences were usually tissue specific but not specific to cancer. However, admixture and pathway analyses suggested some of these differences are causally related to cancer. Specific findings included increased FBXW7 mutations in patients of African origin, decreased VHL and PBRM1 mutations in renal cancer patients of African origin, and decreased immune activity in bladder cancer patients of East Asian origin.
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http://dx.doi.org/10.1016/j.ccell.2020.04.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7328015PMC
May 2020

The Exceptional Responders Initiative: Feasibility of a National Cancer Institute Pilot Study.

J Natl Cancer Inst 2021 01;113(1):27-37

Nationwide Children's Hospital, Columbus, OH, USA; Van Andel Research Institute, Grand Rapids, MI, USA.

Background: Tumor molecular profiling from patients experiencing exceptional responses to systemic therapy may provide insights into cancer biology and improve treatment tailoring. This pilot study evaluates the feasibility of identifying exceptional responders retrospectively, obtaining pre-exceptional response treatment tumor tissues, and analyzing them with state-of-the-art molecular analysis tools to identify potential molecular explanations for responses.

Methods: Exceptional response was defined as partial (PR) or complete (CR) response to a systemic treatment with population PR or CR rate less than 10% or an unusually long response (eg, duration >3 times published median). Cases proposed by patients' clinicians were reviewed by clinical and translational experts. Tumor and normal tissue (if possible) were profiled with whole exome sequencing and, if possible, targeted deep sequencing, RNA sequencing, methylation arrays, and immunohistochemistry. Potential germline mutations were tracked for relevance to disease.

Results: Cases reflected a variety of tumors and standard and investigational treatments. Of 520 cases, 476 (91.5%) were accepted for further review, and 222 of 476 (46.6%) proposed cases met requirements as exceptional responders. Clinical data were obtained from 168 of 222 cases (75.7%). Tumor was provided from 130 of 168 cases (77.4%). Of 117 of the 130 (90.0%) cases with sufficient nucleic acids, 109 (93.2%) were successfully analyzed; 6 patients had potentially actionable germline mutations.

Conclusion: Exceptional responses occur with standard and investigational treatment. Retrospective identification of exceptional responders, accessioning, and sequencing of pretreatment archived tissue is feasible. Data from molecular analyses of tumors, particularly when combining results from patients who received similar treatments, may elucidate molecular bases for exceptional responses.
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http://dx.doi.org/10.1093/jnci/djaa061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7781457PMC
January 2021

Differences in Genome-wide DNA Methylation Profiles in Breast Milk by Race and Lactation Duration.

Cancer Prev Res (Phila) 2019 11 3;12(11):781-790. Epub 2019 Sep 3.

NCI, NIH, Bethesda, Maryland.

Black women in the United States are disproportionately affected by early-onset, triple-negative breast cancer. DNA methylation has shown differences by race in healthy and tumor breast tissues. We examined associations between genome-wide DNA methylation levels in breast milk and breast cancer risk factors, including race, to explain how this reproductive stage influences a woman's risk for, and potentially contributes to racial disparities in, breast cancer. Breast milk samples and demographic, behavioral, and reproductive data, were obtained from cancer-free, uniparous, and lactating U.S. black ( = 57) and white ( = 82) women, ages 19-44. Genome-wide DNA methylation analysis was performed on extracted breast milk DNA using the Infinium HumanMethylation450 BeadChip. Statistically significant associations between breast cancer risk factors and DNA methylation beta values, adjusting for potential confounders, were determined using linear regression followed by Bonferroni Correction ( < 1.63 × 10). Epigenetic analysis in breast milk revealed statistically significant associations with race and lactation duration. Of the 284 CpG sites associated with race, 242 were hypermethylated in black women. All 227 CpG sites associated with lactation duration were hypomethylated in women who lactated longer. Ingenuity Pathway Analysis of differentially methylated promoter region CpGs by race and lactation duration revealed enrichment for networks implicated in carcinogenesis. Associations between DNA methylation and lactation duration may offer insight on its role in lowering breast cancer risk. Epigenetic associations with race may mediate social, behavioral, or other factors related to breast cancer and may provide insight into potential mechanisms underlying racial disparities in breast cancer incidence.
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http://dx.doi.org/10.1158/1940-6207.CAPR-19-0169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825576PMC
November 2019

Before and After: Comparison of Legacy and Harmonized TCGA Genomic Data Commons' Data.

Cell Syst 2019 07;9(1):24-34.e10

National Cancer Institute, Bethesda, MD 20892, USA.

We present a systematic analysis of the effects of synchronizing a large-scale, deeply characterized, multi-omic dataset to the current human reference genome, using updated software, pipelines, and annotations. For each of 5 molecular data platforms in The Cancer Genome Atlas (TCGA)-mRNA and miRNA expression, single nucleotide variants, DNA methylation and copy number alterations-comprehensive sample, gene, and probe-level studies were performed, towards quantifying the degree of similarity between the 'legacy' GRCh37 (hg19) TCGA data and its GRCh38 (hg38) version as 'harmonized' by the Genomic Data Commons. We offer gene lists to elucidate differences that remained after controlling for confounders, and strategies to mitigate their impact on biological interpretation. Our results demonstrate that the hg19 and hg38 TCGA datasets are very highly concordant, promote informed use of either legacy or harmonized omics data, and provide a rubric that encourages similar comparisons as new data emerge and reference data evolve.
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http://dx.doi.org/10.1016/j.cels.2019.06.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6707074PMC
July 2019

Non-invasive diagnosis of early-stage lung cancer using high-throughput targeted DNA methylation sequencing of circulating tumor DNA (ctDNA).

Theranostics 2019 6;9(7):2056-2070. Epub 2019 Apr 6.

First Affiliated Hospital of Guangzhou Department of Thoracic Surgery/Oncology, the First Affiliated Hospital of Guangzhou Medical University; Guangzhou Institute of Respiratory Disease & Health; China State Key Laboratory and National Clinical Research Center for Respiratory Disease, Guangzhou, China.

LDCT screening can identify early-stage lung cancers yet introduces excessive false positives and it remains a great challenge to differentiate malignant tumors from benign solitary pulmonary nodules, which calls for better non-invasive diagnostic tools. We performed DNA methylation profiling by high throughput DNA bisulfite sequencing in tissue samples (nodule size < 3 cm in diameter) to learn methylation patterns that differentiate cancerous tumors from benign lesions. Then we filtered out methylation patterns exhibiting high background in circulating tumor DNA (ctDNA) and built an assay for plasma sample classification. We first performed methylation profiling of 230 tissue samples to learn cancer-specific methylation patterns which achieved a sensitivity of 92.7% (88.3% - 97.1%) and a specificity of 92.8% (89.3% - 96.3%). These tissue-derived DNA methylation markers were further filtered using a training set of 66 plasma samples and 9 markers were selected to build a diagnostic prediction model. From an independent validation set of additional 66 plasma samples, this model obtained a sensitivity of 79.5% (63.5% - 90.7%) and a specificity of 85.2% (66.3% - 95.8%) for differentiating patients with malignant tumor (n = 39) from patients with benign lesions (n = 27). Additionally, when tested on gender and age matched asymptomatic normal individuals (n = 118), our model achieved a specificity of 93.2% (89.0% - 98.3%). Specifically, our assay is highly sensitive towards early-stage lung cancer, with a sensitivity of 75.0% (55.0%-90.0%) in 20 stage Ia lung cancer patients and 85.7% (57.1%-100.0%) in 7 stage Ib lung cancer patients. We have developed a novel sensitive blood based non-invasive diagnostic assay for detecting early stage lung cancer as well as differentiating lung cancers from benign pulmonary nodules.
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http://dx.doi.org/10.7150/thno.28119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485294PMC
April 2020

In vivo Application of the REMOTE-control System for the Manipulation of Endogenous Gene Expression.

J Vis Exp 2019 03 29(145). Epub 2019 Mar 29.

Center for Epigenetics, Van Andel Research Institute;

Here we describe a protocol for implementing the REMOTE-control system (Reversible Manipulation of Transcription at Endogenous loci), which allows for reversible and tunable expression control of an endogenous gene of interest in living model systems. The REMOTE-control system employs enhanced lac repression and tet activation systems to achieve down- or upregulation of a target gene within a single biological system. Tight repression can be achieved from repressor binding sites flexibly located far downstream of a transcription start site by inhibiting transcription elongation. Robust upregulation can be attained by enhancing the transcription of an endogenous gene by targeting tet transcriptional activators to the cognate promoter. This reversible and tunable expression control can be applied and withdrawn repeatedly in organisms. The potency and versatility of the system, as demonstrated for endogenous Dnmt1 here, will allow more precise in vivo functional analyses by enabling investigation of gene function at various expression levels and by testing the reversibility of a phenotype.
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http://dx.doi.org/10.3791/59235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520982PMC
March 2019

The chromatin accessibility landscape of primary human cancers.

Science 2018 10;362(6413)

We present the genome-wide chromatin accessibility profiles of 410 tumor samples spanning 23 cancer types from The Cancer Genome Atlas (TCGA). We identify 562,709 transposase-accessible DNA elements that substantially extend the compendium of known cis-regulatory elements. Integration of ATAC-seq (the assay for transposase-accessible chromatin using sequencing) with TCGA multi-omic data identifies a large number of putative distal enhancers that distinguish molecular subtypes of cancers, uncovers specific driving transcription factors via protein-DNA footprints, and nominates long-range gene-regulatory interactions in cancer. These data reveal genetic risk loci of cancer predisposition as active DNA regulatory elements in cancer, identify gene-regulatory interactions underlying cancer immune evasion, and pinpoint noncoding mutations that drive enhancer activation and may affect patient survival. These results suggest a systematic approach to understanding the noncoding genome in cancer to advance diagnosis and therapy.
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http://dx.doi.org/10.1126/science.aav1898DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6408149PMC
October 2018

SeSAMe: reducing artifactual detection of DNA methylation by Infinium BeadChips in genomic deletions.

Nucleic Acids Res 2018 11;46(20):e123

Center for Epigenetics, Van Andel Research Institute, 333 Bostwick Ave., N.E., Grand Rapids, MI 49503 USA.

We report a new class of artifacts in DNA methylation measurements from Illumina HumanMethylation450 and MethylationEPIC arrays. These artifacts reflect failed hybridization to target DNA, often due to germline or somatic deletions and manifest as incorrectly reported intermediate methylation. The artifacts often survive existing preprocessing pipelines, masquerade as epigenetic alterations and can confound discoveries in epigenome-wide association studies and studies of methylation-quantitative trait loci. We implement a solution, P-value with out-of-band (OOB) array hybridization (pOOBAH), in the R package SeSAMe. Our method effectively masks deleted and hyperpolymorphic regions, reducing or eliminating spurious reports of epigenetic silencing at oft-deleted tumor suppressor genes such as CDKN2A and RB1 in cases with somatic deletions. Furthermore, our method substantially decreases technical variation whilst retaining biological variation, both within and across HM450 and EPIC platform measurements. SeSAMe provides a light-weight, modular DNA methylation data analysis suite, with a performant implementation suitable for efficient analysis of thousands of samples.
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http://dx.doi.org/10.1093/nar/gky691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6237738PMC
November 2018

Integrated Molecular Characterization of Testicular Germ Cell Tumors.

Cell Rep 2018 06;23(11):3392-3406

The Eli and Edythe L. Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02142, USA.

We studied 137 primary testicular germ cell tumors (TGCTs) using high-dimensional assays of genomic, epigenomic, transcriptomic, and proteomic features. These tumors exhibited high aneuploidy and a paucity of somatic mutations. Somatic mutation of only three genes achieved significance-KIT, KRAS, and NRAS-exclusively in samples with seminoma components. Integrated analyses identified distinct molecular patterns that characterized the major recognized histologic subtypes of TGCT: seminoma, embryonal carcinoma, yolk sac tumor, and teratoma. Striking differences in global DNA methylation and microRNA expression between histology subtypes highlight a likely role of epigenomic processes in determining histologic fates in TGCTs. We also identified a subset of pure seminomas defined by KIT mutations, increased immune infiltration, globally demethylated DNA, and decreased KRAS copy number. We report potential biomarkers for risk stratification, such as miRNA specifically expressed in teratoma, and others with molecular diagnostic potential, such as CpH (CpA/CpC/CpT) methylation identifying embryonal carcinomas.
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http://dx.doi.org/10.1016/j.celrep.2018.05.039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6075738PMC
June 2018

A Distinct DNA Methylation Shift in a Subset of Glioma CpG Island Methylator Phenotypes during Tumor Recurrence.

Cell Rep 2018 Apr;23(2):637-651

Department of Neurosurgery, Henry Ford Health System, Detroit, MI 48202, USA; Department of Genetics, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil. Electronic address:

Glioma diagnosis is based on histomorphology and grading; however, such classification does not have predictive clinical outcome after glioblastomas have developed. To date, no bona fide biomarkers that significantly translate into a survival benefit to glioblastoma patients have been identified. We previously reported that the IDH mutant G-CIMP-high subtype would be a predecessor to the G-CIMP-low subtype. Here, we performed a comprehensive DNA methylation longitudinal analysis of diffuse gliomas from 77 patients (200 tumors) to enlighten the epigenome-based malignant transformation of initially lower-grade gliomas. Intra-subtype heterogeneity among G-CIMP-high primary tumors allowed us to identify predictive biomarkers for assessing the risk of malignant recurrence at early stages of disease. G-CIMP-low recurrence appeared in 9.5% of all gliomas, and these resembled IDH-wild-type primary glioblastoma. G-CIMP-low recurrence can be characterized by distinct epigenetic changes at candidate functional tissue enhancers with AP-1/SOX binding elements, mesenchymal stem cell-like epigenomic phenotype, and genomic instability. Molecular abnormalities of longitudinal G-CIMP offer possibilities to defy glioblastoma progression.
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http://dx.doi.org/10.1016/j.celrep.2018.03.107DOI Listing
April 2018

Machine Learning Identifies Stemness Features Associated with Oncogenic Dedifferentiation.

Cell 2018 04;173(2):338-354.e15

Poznań University of Medical Sciences, 61701 Poznań, Poland; Greater Poland Cancer Center, 61866 Poznań, Poland; International Institute for Molecular Oncology, 60203 Poznań, Poland. Electronic address:

Cancer progression involves the gradual loss of a differentiated phenotype and acquisition of progenitor and stem-cell-like features. Here, we provide novel stemness indices for assessing the degree of oncogenic dedifferentiation. We used an innovative one-class logistic regression (OCLR) machine-learning algorithm to extract transcriptomic and epigenetic feature sets derived from non-transformed pluripotent stem cells and their differentiated progeny. Using OCLR, we were able to identify previously undiscovered biological mechanisms associated with the dedifferentiated oncogenic state. Analyses of the tumor microenvironment revealed unanticipated correlation of cancer stemness with immune checkpoint expression and infiltrating immune cells. We found that the dedifferentiated oncogenic phenotype was generally most prominent in metastatic tumors. Application of our stemness indices to single-cell data revealed patterns of intra-tumor molecular heterogeneity. Finally, the indices allowed for the identification of novel targets and possible targeted therapies aimed at tumor differentiation.
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http://dx.doi.org/10.1016/j.cell.2018.03.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5902191PMC
April 2018

Oncogenic Signaling Pathways in The Cancer Genome Atlas.

Cell 2018 04;173(2):321-337.e10

Van Andel Research Institute, 333 Bostwick Ave NE, Grand Rapids Michigan, 49503, USA.

Genetic alterations in signaling pathways that control cell-cycle progression, apoptosis, and cell growth are common hallmarks of cancer, but the extent, mechanisms, and co-occurrence of alterations in these pathways differ between individual tumors and tumor types. Using mutations, copy-number changes, mRNA expression, gene fusions and DNA methylation in 9,125 tumors profiled by The Cancer Genome Atlas (TCGA), we analyzed the mechanisms and patterns of somatic alterations in ten canonical pathways: cell cycle, Hippo, Myc, Notch, Nrf2, PI-3-Kinase/Akt, RTK-RAS, TGFβ signaling, p53 and β-catenin/Wnt. We charted the detailed landscape of pathway alterations in 33 cancer types, stratified into 64 subtypes, and identified patterns of co-occurrence and mutual exclusivity. Eighty-nine percent of tumors had at least one driver alteration in these pathways, and 57% percent of tumors had at least one alteration potentially targetable by currently available drugs. Thirty percent of tumors had multiple targetable alterations, indicating opportunities for combination therapy.
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http://dx.doi.org/10.1016/j.cell.2018.03.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6070353PMC
April 2018

Cell-of-Origin Patterns Dominate the Molecular Classification of 10,000 Tumors from 33 Types of Cancer.

Cell 2018 04;173(2):291-304.e6

Van Andel Research Institute, Grand Rapids, MI 49503, USA. Electronic address:

We conducted comprehensive integrative molecular analyses of the complete set of tumors in The Cancer Genome Atlas (TCGA), consisting of approximately 10,000 specimens and representing 33 types of cancer. We performed molecular clustering using data on chromosome-arm-level aneuploidy, DNA hypermethylation, mRNA, and miRNA expression levels and reverse-phase protein arrays, of which all, except for aneuploidy, revealed clustering primarily organized by histology, tissue type, or anatomic origin. The influence of cell type was evident in DNA-methylation-based clustering, even after excluding sites with known preexisting tissue-type-specific methylation. Integrative clustering further emphasized the dominant role of cell-of-origin patterns. Molecular similarities among histologically or anatomically related cancer types provide a basis for focused pan-cancer analyses, such as pan-gastrointestinal, pan-gynecological, pan-kidney, and pan-squamous cancers, and those related by stemness features, which in turn may inform strategies for future therapeutic development.
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http://dx.doi.org/10.1016/j.cell.2018.03.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5957518PMC
April 2018

Comparative Molecular Analysis of Gastrointestinal Adenocarcinomas.

Cancer Cell 2018 04 2;33(4):721-735.e8. Epub 2018 Apr 2.

Center for Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA. Electronic address:

We analyzed 921 adenocarcinomas of the esophagus, stomach, colon, and rectum to examine shared and distinguishing molecular characteristics of gastrointestinal tract adenocarcinomas (GIACs). Hypermutated tumors were distinct regardless of cancer type and comprised those enriched for insertions/deletions, representing microsatellite instability cases with epigenetic silencing of MLH1 in the context of CpG island methylator phenotype, plus tumors with elevated single-nucleotide variants associated with mutations in POLE. Tumors with chromosomal instability were diverse, with gastroesophageal adenocarcinomas harboring fragmented genomes associated with genomic doubling and distinct mutational signatures. We identified a group of tumors in the colon and rectum lacking hypermutation and aneuploidy termed genome stable and enriched in DNA hypermethylation and mutations in KRAS, SOX9, and PCBP1.
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http://dx.doi.org/10.1016/j.ccell.2018.03.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5966039PMC
April 2018

Genomic and Molecular Landscape of DNA Damage Repair Deficiency across The Cancer Genome Atlas.

Cell Rep 2018 04;23(1):239-254.e6

Department of Experimental Radiation Oncology, University of Texas MD Anderson Cancer, Houston, TX 77030, USA.

DNA damage repair (DDR) pathways modulate cancer risk, progression, and therapeutic response. We systematically analyzed somatic alterations to provide a comprehensive view of DDR deficiency across 33 cancer types. Mutations with accompanying loss of heterozygosity were observed in over 1/3 of DDR genes, including TP53 and BRCA1/2. Other prevalent alterations included epigenetic silencing of the direct repair genes EXO5, MGMT, and ALKBH3 in ∼20% of samples. Homologous recombination deficiency (HRD) was present at varying frequency in many cancer types, most notably ovarian cancer. However, in contrast to ovarian cancer, HRD was associated with worse outcomes in several other cancers. Protein structure-based analyses allowed us to predict functional consequences of rare, recurrent DDR mutations. A new machine-learning-based classifier developed from gene expression data allowed us to identify alterations that phenocopy deleterious TP53 mutations. These frequent DDR gene alterations in many human cancers have functional consequences that may determine cancer progression and guide therapy.
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http://dx.doi.org/10.1016/j.celrep.2018.03.076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5961503PMC
April 2018

Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas.

Cell Rep 2018 04;23(1):194-212.e6

Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smoking and/or human papillomavirus (HPV). SCCs harbor 3q, 5p, and other recurrent chromosomal copy-number alterations (CNAs), DNA mutations, and/or aberrant methylation of genes and microRNAs, which are correlated with the expression of multi-gene programs linked to squamous cell stemness, epithelial-to-mesenchymal differentiation, growth, genomic integrity, oxidative damage, death, and inflammation. Low-CNA SCCs tended to be HPV(+) and display hypermethylation with repression of TET1 demethylase and FANCF, previously linked to predisposition to SCC, or harbor mutations affecting CASP8, RAS-MAPK pathways, chromatin modifiers, and immunoregulatory molecules. We uncovered hypomethylation of the alternative promoter that drives expression of the ΔNp63 oncogene and embedded miR944. Co-expression of immune checkpoint, T-regulatory, and Myeloid suppressor cells signatures may explain reduced efficacy of immune therapy. These findings support possibilities for molecular classification and therapeutic approaches.
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http://dx.doi.org/10.1016/j.celrep.2018.03.063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6002769PMC
April 2018

DNA methylation loss in late-replicating domains is linked to mitotic cell division.

Nat Genet 2018 04 2;50(4):591-602. Epub 2018 Apr 2.

Center for Bioinformatics and Functional Genomics, Cedars-Sinai Medical Center, Los Angeles, CA, USA.

DNA methylation loss occurs frequently in cancer genomes, primarily within lamina-associated, late-replicating regions termed partially methylated domains (PMDs). We profiled 39 diverse primary tumors and 8 matched adjacent tissues using whole-genome bisulfite sequencing (WGBS) and analyzed them alongside 343 additional human and 206 mouse WGBS datasets. We identified a local CpG sequence context associated with preferential hypomethylation in PMDs. Analysis of CpGs in this context ('solo-WCGWs') identified previously undetected PMD hypomethylation in almost all healthy tissue types. PMD hypomethylation increased with age, beginning during fetal development, and appeared to track the accumulation of cell divisions. In cancer, PMD hypomethylation depth correlated with somatic mutation density and cell cycle gene expression, consistent with its reflection of mitotic history and suggesting its application as a mitotic clock. We propose that late replication leads to lifelong progressive methylation loss, which acts as a biomarker for cellular aging and which may contribute to oncogenesis.
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http://dx.doi.org/10.1038/s41588-018-0073-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893360PMC
April 2018

MethyLight and Digital MethyLight.

Methods Mol Biol 2018 ;1708:497-513

Van Andel Research Institute, Center for Epigenetics, Room 5006W, 333 Bostwick Ave., N.E., Grand Rapids, MI, 49503, USA.

MethyLight is a quantitative, fluorescence-based, real-time PCR method to sensitively detect and quantify DNA methylation of candidate regions of the genome. MethyLight is uniquely suited for detecting low-frequency methylated DNA regions against a high background of unmethylated DNA, as it combines methylation-specific priming with methylation-specific fluorescent probing. The quantitative accuracy of real-time PCR and the ability to design bisulfite-dependent, DNA methylation-independent control reactions together allow for a quantitative assessment of these low frequency methylation events. Here we describe the experimental steps of MethyLight analysis in detail. Furthermore, we present principles and design examples for three types of quality control reactions. QC-1 reactions are methylation-independent reactions to monitor sample quantity and integrity. QC-2 reactions are bisulfite-independent reactions to monitor recovery efficiencies of the bisulfite conversion methodology used. QC-3 reactions are bisulfite-independently primed reactions with variable bisulfite-dependent probing to monitor completeness of the sodium bisulfite treatment. We show that these control reactions perform as expected in a time course experiment interrupting sodium bisulfite conversion at various timepoints. Finally, we describe Digital MethyLight, in which MethyLight is combined with Digital PCR, for the highly sensitive detection of individual methylated molecules, with use in disease detection and screening.
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http://dx.doi.org/10.1007/978-1-4939-7481-8_25DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7450695PMC
July 2018

Comprehensive Molecular Characterization of Muscle-Invasive Bladder Cancer.

Cell 2017 Oct 5;171(3):540-556.e25. Epub 2017 Oct 5.

Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.

We report a comprehensive analysis of 412 muscle-invasive bladder cancers characterized by multiple TCGA analytical platforms. Fifty-eight genes were significantly mutated, and the overall mutational load was associated with APOBEC-signature mutagenesis. Clustering by mutation signature identified a high-mutation subset with 75% 5-year survival. mRNA expression clustering refined prior clustering analyses and identified a poor-survival "neuronal" subtype in which the majority of tumors lacked small cell or neuroendocrine histology. Clustering by mRNA, long non-coding RNA (lncRNA), and miRNA expression converged to identify subsets with differential epithelial-mesenchymal transition status, carcinoma in situ scores, histologic features, and survival. Our analyses identified 5 expression subtypes that may stratify response to different treatments.
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http://dx.doi.org/10.1016/j.cell.2017.09.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5687509PMC
October 2017

The REMOTE-control system: a system for reversible and tunable control of endogenous gene expression in mice.

Nucleic Acids Res 2017 Dec;45(21):12256-12269

Center for Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA.

We report here a robust, tunable, and reversible transcription control system for endogenous genes. The REMOTE-control system (Reversible Manipulation of Transcription at Endogenous loci) employs enhanced lac repression and tet activation systems. With this approach, we show in mouse embryonic stem cells that endogenous Dnmt1 gene transcription could be up- or downregulated in a tunable, inducible, and reversible manner across nearly two orders of magnitude. Transcriptional repression of Dnmt1 by REMOTE-control was potent enough to cause embryonic lethality in mice, reminiscent of a genetic knockout of Dnmt1 and could substantially suppress intestinal polyp formation when applied to an ApcMin model. Binding by the enhanced lac repressor was sufficiently tight to allow strong attenuation of transcriptional elongation, even at operators located many kilobases downstream of the transcription start site and to produce invariably tight repression of all of the strong viral/mammalian promoters tested. Our approach of targeting tet transcriptional activators to the endogenous Dnmt1 promoter resulted in robust upregulation of this highly expressed housekeeping gene. Our system provides exquisite control of the level, timing, and cell-type specificity of endogenous gene expression, and the potency and versatility of the system will enable high resolution in vivo functional analyses.
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http://dx.doi.org/10.1093/nar/gkx829DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5716148PMC
December 2017

Association of high microvessel αβ and low PTEN with poor outcome in stage 3 neuroblastoma: rationale for using first in class dual PI3K/BRD4 inhibitor, SF1126.

Oncotarget 2017 Aug 18;8(32):52193-52210. Epub 2016 Nov 18.

Department of Pediatrics, Moores Cancer Center, University of California San Diego, California, USA.

Neuroblastoma (NB) is the most common extracranial solid tumor in children. Our previous studies showed that the angiogenic integrin αβ was increased in high-risk metastatic (stage 4) NB compared with localized neuroblastomas. Herein, we show that integrin αβ was expressed on 68% of microvessels in MYCN-amplified stage 3 neuroblastomas, but only on 34% (means) in MYCN-non-amplified tumors ( < 0.001; = 54). PTEN, a tumor suppressor involved in αβ signaling, was expressed in neuroblastomas either diffusely, focally or not at all (immunohistochemistry). Integrin αβ was expressed on 60% of tumor microvessels when PTEN was negative or focal, as compared to 32% of microvessels in tumors with diffuse PTEN expression ( < 0.001). In a MYCN transgenic mouse model, loss of one allele of PTEN promoted tumor growth, illustrating the potential role of PTEN in neuroblastoma pathogenesis. Interestingly, we report the novel dual PI-3K/BRD4 activity of SF1126 (originally developed as an RGD-conjugated pan PI3K inhibitor). SF1126 inhibits BRD4 bromodomain binding to acetylated lysine residues with histone H3 as well as PI3K activity in the MYCN amplified neuroblastoma cell line IMR-32. Moreover, SF1126 suppressed MYCN expression and MYCN associated transcriptional activity in IMR-32 and CHLA136, resulting in overall decrease in neuroblastoma cell viability. Finally, treatment of neuroblastoma tumors with SF1126 inhibited neuroblastoma growth . These data suggest integrin αβ, MYCN/BRD4 and PTEN/PI3K/AKT signaling as biomarkers and hence therapeutic targets in neuroblastoma and support testing of the RGD integrin αβ-targeted PI-3K/BRD4 inhibitor, SF1126 as a therapeutic strategy in this specific subgroup of high risk neuroblastoma.
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http://dx.doi.org/10.18632/oncotarget.13386DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5581022PMC
August 2017

A mutational signature reveals alterations underlying deficient homologous recombination repair in breast cancer.

Nat Genet 2017 Oct 21;49(10):1476-1486. Epub 2017 Aug 21.

Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.

Biallelic inactivation of BRCA1 or BRCA2 is associated with a pattern of genome-wide mutations known as signature 3. By analyzing ∼1,000 breast cancer samples, we confirmed this association and established that germline nonsense and frameshift variants in PALB2, but not in ATM or CHEK2, can also give rise to the same signature. We were able to accurately classify missense BRCA1 or BRCA2 variants known to impair homologous recombination (HR) on the basis of this signature. Finally, we show that epigenetic silencing of RAD51C and BRCA1 by promoter methylation is strongly associated with signature 3 and, in our data set, was highly enriched in basal-like breast cancers in young individuals of African descent.
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http://dx.doi.org/10.1038/ng.3934DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7376751PMC
October 2017

Comparison of Breast Cancer Molecular Features and Survival by African and European Ancestry in The Cancer Genome Atlas.

JAMA Oncol 2017 12;3(12):1654-1662

Center for Clinical Cancer Genetics, Department of Medicine, The University of Chicago, Chicago, Illinois

Importance: African Americans have the highest breast cancer mortality rate. Although racial difference in the distribution of intrinsic subtypes of breast cancer is known, it is unclear if there are other inherent genomic differences that contribute to the survival disparities.

Objectives: To investigate racial differences in breast cancer molecular features and survival and to estimate the heritability of breast cancer subtypes.

Design, Setting, And Participants: Among a convenience cohort of patients with invasive breast cancer, breast tumor and matched normal tissue sample data (as of September 18, 2015) were obtained from The Cancer Genome Atlas.

Main Outcomes And Measures: Breast cancer–free interval, tumor molecular features, and genetic variants.

Results: Participants were 930 patients with breast cancer, including 154 black patients of African ancestry (mean [SD] age at diagnosis, 55.66 [13.01] years; 98.1% [n = 151] female) and 776 white patients of European ancestry (mean [SD] age at diagnosis, 59.51 [13.11] years; 99.0% [n = 768] female). Compared with white patients, black patients had a worse breast cancer-free interval (hazard ratio, HR=1.67; 95% CI, 1.02-2.74; P = .043). They had a higher likelihood of basal-like (odds ratio, 3.80; 95% CI, 2.46-5.87; P < .001) and human epidermal growth factor receptor 2 (ERBB2 [formerly HER2])–enriched (odds ratio, 2.22; 95% CI, 1.10-4.47; P = .027) breast cancer subtypes, with the Luminal A subtype as the reference. Blacks had more TP53 mutations and fewer PIK3CA mutations than whites. While most molecular differences were eliminated after adjusting for intrinsic subtype, the study found 16 DNA methylation probes, 4 DNA copy number segments, 1 protein, and 142 genes that were differentially expressed, with the gene-based signature having an excellent capacity for distinguishing breast tumors from black vs white patients (cross-validation C index, 0.878). Using germline genotypes, the heritability of breast cancer subtypes (basal vs nonbasal) was estimated to be 0.436 (P = 1.5 × 10−14). The estrogen receptor–positive polygenic risk score built from 89 known susceptibility variants was higher in blacks than in whites (difference, 0.24; P = 2.3 × 10−5), while the estrogen receptor–negative polygenic risk score was much higher in blacks than in whites (difference, 0.48; P = 2.8 × 10−11).

Conclusions And Relevance: On the molecular level, after adjusting for intrinsic subtype frequency differences, this study found a modest number of genomic differences but a significant clinical survival outcome difference between blacks and whites in The Cancer Genome Atlas data set. Moreover, more than 40% of breast cancer subtype frequency differences could be explained by genetic variants. These data could form the basis for the development of molecular targeted therapies to improve clinical outcomes for the specific subtypes of breast cancers that disproportionately affect black women. Findings also indicate that personalized risk assessment and optimal treatment could reduce deaths from aggressive breast cancers for black women.
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http://dx.doi.org/10.1001/jamaoncol.2017.0595DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5671371PMC
December 2017
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