Publications by authors named "Mia S Bertalan"

8 Publications

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Exploring Predictors of Response to Dacomitinib in -Amplified Recurrent Glioblastoma.

JCO Precis Oncol 2020 8;4. Epub 2020 Jun 8.

Massachusetts General Hospital and Harvard Medical School, Boston, MA.

Purpose: Despite the high frequency of genetic alterations in glioblastoma (GBM), EGFR-targeted therapies have not had success in this disease. To improve the likelihood of efficacy, we targeted adult patients with recurrent GBM enriched for gene amplification, which occurs in approximately half of GBM, with dacomitinib, a second-generation, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that penetrates the blood-brain barrier, in a multicenter phase II trial.

Patients And Methods: We retrospectively explored whether previously described extracellular domain (ECD)-sensitizing mutations in the context of gene amplification could predict response to dacomitinib, and in a predefined subset of patients, we measured post-treatment intratumoral dacomitinib levels to verify tumor penetration.

Results: We found that dacomitinib effectively penetrates contrast-enhancing GBM tumors. Among all 56 treated patients, 8 (14.3%) had a clinical benefit as defined by a duration of treatment of at least 6 months, of whom 5 (8.9%) remained progression free for at least 1 year. Presence of or ECD missense mutation was not associated with clinical benefit. We evaluated the pretreatment transcriptome in circulating extracellular vesicles (EVs) by RNA sequencing in a subset of patients and identified a signature that distinguished patients who had durable benefit versus those with rapid progression.

Conclusion: While dacomitinib was not effective in most patients with -amplified GBM, a subset experienced a durable, clinically meaningful benefit. Moreover, and ECD mutation status in archival tumors did not predict clinical benefit. RNA signatures in circulating EVs may warrant investigation as biomarkers of dacomitinib efficacy in GBM.
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http://dx.doi.org/10.1200/PO.19.00295DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446412PMC
June 2020

Single-arm, open-label phase 2 trial of pembrolizumab in patients with leptomeningeal carcinomatosis.

Nat Med 2020 08 2;26(8):1280-1284. Epub 2020 Jun 2.

Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.

An increasing fraction of patients with metastatic cancer develop leptomeningeal dissemination of disease (LMD), and survival is dismal. We conducted a single-arm, phase 2 study of pembrolizumab in patients with solid tumor malignancies and LMD (NCT02886585). Patients received 200 mg of pembrolizumab intravenously every 3 weeks until definitive progression or unacceptable toxicity. The primary endpoint was rate of overall survival at 3 months (OS3). Secondary objectives included toxicity, response rate and time to intracranial or extracranial disease progression. A Simon two-stage design was used to compare a null hypothesis OS3 of 18% against an alternative of 43%. Twenty patients-17 with breast cancer, two with lung cancer and one with ovarian cancer-were enrolled into the pre-specified evaluation group having received at least one dose of pembrolizumab. The median follow-up of surviving patients was 6.3 months (range, 2.2-12.5 months). The percentage of patients who experienced one (or more) grade 3 or higher adverse events at least possibly related to treatment was 40%, the most frequent being hyperglycemia (n = 6), nausea (n = 7) and vomiting (n = 7). The study met the primary endpoint, as 12 of 20 (OS3, 0.60; 90% confidence interval, 0.39-0.78) patients were alive at 3 months after enrollment. Pembrolizumab is safe and feasible and displays promising activity in patients with LMD. Further investigations are needed to identify which patients with LMD can benefit from pembrolizumab.
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http://dx.doi.org/10.1038/s41591-020-0918-0DOI Listing
August 2020

An Integrative Model of Cellular States, Plasticity, and Genetics for Glioblastoma.

Cell 2019 08 18;178(4):835-849.e21. Epub 2019 Jul 18.

Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA; Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA. Electronic address:

Diverse genetic, epigenetic, and developmental programs drive glioblastoma, an incurable and poorly understood tumor, but their precise characterization remains challenging. Here, we use an integrative approach spanning single-cell RNA-sequencing of 28 tumors, bulk genetic and expression analysis of 401 specimens from the The Cancer Genome Atlas (TCGA), functional approaches, and single-cell lineage tracing to derive a unified model of cellular states and genetic diversity in glioblastoma. We find that malignant cells in glioblastoma exist in four main cellular states that recapitulate distinct neural cell types, are influenced by the tumor microenvironment, and exhibit plasticity. The relative frequency of cells in each state varies between glioblastoma samples and is influenced by copy number amplifications of the CDK4, EGFR, and PDGFRA loci and by mutations in the NF1 locus, which each favor a defined state. Our work provides a blueprint for glioblastoma, integrating the malignant cell programs, their plasticity, and their modulation by genetic drivers.
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http://dx.doi.org/10.1016/j.cell.2019.06.024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6703186PMC
August 2019

A Clinical Rule for Preoperative Prediction of BRAF Mutation Status in Craniopharyngiomas.

Neurosurgery 2019 08;85(2):204-210

Divisions of Neuro-Oncology and Hematology/Oncology, Departments of Medicine and Neurology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts.

Background: Papillary craniopharyngiomas are characterized by BRAFV600E mutations. Targeted therapy can elicit a dramatic radiographic regression of these tumors. Therefore, prediction of BRAF mutation status before definitive surgery could enable neoadjuvant treatment strategies.

Objective: To establish preoperative prediction criteria to identify patients with a BRAF mutant craniopharyngioma.

Methods: Sixty-four patients with craniopharyngioma were included in this study. We determined BRAF mutation status by targeted sequencing. After scoring interobserver variability between presurgical clinical data and radiographic features, we established a diagnostic rule for BRAF mutation in our discovery cohort. We then validated the rule in an independent cohort.

Results: The BRAFV600E mutation was detected in 12 of 42 patients in the discovery cohort. There were no patients under age 18 with BRAF mutation. Calcification was rare in tumors with BRAF mutation (P < .001), and 92% of them were supradiaphragmatic in location. Combining these 3 features-older than 18 years, absence of calcification, and supradiaphragmatic tumor location-we established a rule for predicting BRAF mutation. In cases where all 3 criteria were fulfilled, the sensitivity and specificity for the presence of BRAF mutation were 83% and 93%, respectively. In the validation cohort (n = 22), the sensitivity was 100% and specificity was 89%.

Conclusion: We propose predictive criteria for a BRAF mutation in craniopharyngioma using preoperative clinical and radiographic data. This rule may be useful in identifying patients who could potentially benefit from neoadjuvant BRAFV600E-targeted systemic therapies.
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http://dx.doi.org/10.1093/neuros/nyy569DOI Listing
August 2019

DMD genomic deletions characterize a subset of progressive/higher-grade meningiomas with poor outcome.

Acta Neuropathol 2018 11 19;136(5):779-792. Epub 2018 Aug 19.

Stephen E. and Catherine Pappas Center for Neuro-Oncology, Divisions of Hematology/Oncology and Neuro-Oncology, Departments of Medicine and Neurology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA, 02114, USA.

Progressive meningiomas that have failed surgery and radiation have a poor prognosis and no standard therapy. While meningiomas are more common in females overall, progressive meningiomas are enriched in males. We performed a comprehensive molecular characterization of 169 meningiomas from 53 patients with progressive/high-grade tumors, including matched primary and recurrent samples. Exome sequencing in an initial cohort (n = 24) detected frequent alterations in genes residing on the X chromosome, with somatic intragenic deletions of the dystrophin-encoding and muscular dystrophy-associated DMD gene as the most common alteration (n = 5, 20.8%), along with alterations of other known X-linked cancer-related genes KDM6A (n =2, 8.3%), DDX3X, RBM10 and STAG2 (n = 1, 4.1% each). DMD inactivation (by genomic deletion or loss of protein expression) was ultimately detected in 17/53 progressive meningioma patients (32%). Importantly, patients with tumors harboring DMD inactivation had a shorter overall survival (OS) than their wild-type counterparts [5.1 years (95% CI 1.3-9.0) vs. median not reached (95% CI 2.9-not reached, p = 0.006)]. Given the known poor prognostic association of TERT alterations in these tumors, we also assessed for these events, and found seven patients with TERT promoter mutations and three with TERT rearrangements in this cohort (n = 10, 18.8%), including a recurrent novel RETREG1-TERT rearrangement that was present in two patients. In a multivariate model, DMD inactivation (p = 0.033, HR = 2.6, 95% CI 1.0-6.6) and TERT alterations (p = 0.005, HR = 3.8, 95% CI 1.5-9.9) were mutually independent in predicting unfavorable outcomes. Thus, DMD alterations identify a subset of progressive/high-grade meningiomas with worse outcomes.
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http://dx.doi.org/10.1007/s00401-018-1899-7DOI Listing
November 2018

Resolving the phylogenetic origin of glioblastoma via multifocal genomic analysis of pre-treatment and treatment-resistant autopsy specimens.

NPJ Precis Oncol 2017 18;1(1):33. Epub 2017 Sep 18.

1Division of Hematology/Oncology, Massachusetts General Hospital, Boston, Massachusetts USA.

Glioblastomas are malignant neoplasms composed of diverse cell populations. This intratumoral diversity has an underlying architecture, with a hierarchical relationship through clonal evolution from a common ancestor. Therapies are limited by emergence of resistant subclones from this phylogenetic reservoir. To characterize this clonal ancestral origin of recurrent tumors, we determined phylogenetic relationships using whole exome sequencing of pre-treatment IDH1/2 wild-type glioblastoma specimens, matched to post-treatment autopsy samples ( = 9) and metastatic extracranial post-treatment autopsy samples ( = 3). We identified "truncal" genetic events common to the evolutionary ancestry of the initial specimen and later recurrences, thereby inferring the identity of the precursor cell population. Mutations were identified in a subset of cases in known glioblastoma genes such as ( = 3), ( = 4) and ( = 5). However, by phylogenetic analysis, there were no protein-coding mutations as recurrent truncal events across the majority of cases. In contrast, whole copy-loss of chromosome 10 (12 of 12 cases), copy-loss of chromosome 9p21 (11 of 12 cases) and copy-gain in chromosome 7 (10 of 12 cases) were identified as shared events in the majority of cases. Strikingly, mutations in the promoter were also identified as shared events in all evaluated pairs (9 of 9). Thus, we define four truncal non-coding genomic alterations that represent early genomic events in gliomagenesis, that identify the persistent cellular reservoir from which glioblastoma recurrences emerge. Therapies to target these key early genomic events are needed. These findings offer an evolutionary explanation for why precision therapies that target protein-coding mutations lack efficacy in GBM.
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http://dx.doi.org/10.1038/s41698-017-0035-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5871833PMC
September 2017

Leptomeningeal metastasis from systemic cancer: Review and update on management.

Cancer 2018 Jan 22;124(1):21-35. Epub 2017 Nov 22.

Division of Neuro-Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.

Leptomeningeal metastasis is an uncommon and typically late complication of cancer with a poor prognosis and limited treatment options. Diagnosis is often challenging, with nonspecific presenting symptoms ranging from headache and confusion to focal neurologic deficits, such as cranial nerve palsies. Standard diagnostic evaluation involves a neurologic examination, magnetic resonance imaging of the brain and spine with gadolinium, and cytologic evaluation of the cerebral spinal fluid. Therapy entails a multimodal approach focused on palliation with surgery, radiation, and/or chemotherapy, which may be administered systemically or directly into the cerebral spinal fluid. Limited trial data exist to guide treatment, and current regimens are based primarily on expert opinion. Although newer targeted and immunotherapeutic agents are under investigation and have shown promise, an improved understanding of the biology of leptomeningeal metastasis and treatment resistance as well as additional randomized controlled studies are needed to guide the optimal treatment of this devastating disease. Cancer 2018;124:21-35. © 2017 American Cancer Society.
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http://dx.doi.org/10.1002/cncr.30911DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418844PMC
January 2018