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Accurate ancestry inference is critical for identifying genetic contributors of cancer disparities among populations. Although methods to infer genetic ancestry have historically relied upon genome-wide markers, the adaptation to targeted clinical sequencing panels presents an opportunity to incorporate ancestry inference into routine diagnostic workflows. We show that global ancestral contributions and admixture of continental populations can be quantitatively inferred using markers captured by the MSK-IMPACT clinical panel. In a pan-cancer cohort of 45,157 patients, we observed differences by ancestry in the frequency of somatic alterations, recapitulating known associations and revealing novel associations. Despite the comparable overall prevalence of driver alterations by ancestry group, the proportion of patients with clinically actionable alterations was lower for African (30%) compared with European (33%) ancestry. Although this result is largely explained by population-specific cancer subtype differences, it reveals an inequity in the degree to which different populations are served by existing precision oncology interventions. Significance: We performed a comprehensive analysis of ancestral associations with somatic mutations in a real-world pan-cancer cohort, including >5,000 non-European individuals. Using an FDA-authorized tumor sequencing panel and an FDA-recognized oncology knowledge base, we detected differences in the prevalence of clinically actionable alterations, potentially contributing to health care disparities affecting underrepresented populations. This article is highlighted in the In This Issue feature, p. 2483

Supplementary Figure from Genetic Ancestry Correlates with Somatic Differences in a Real-World Clinical Cancer Sequencing Cohort

Accurate ancestry inference is critical for identifying genetic contributors of cancer disparities among populations. Although methods to infer genetic ancestry have historically relied upon genome-wide markers, the adaptation to targeted clinical sequencing panels presents an opportunity to incorporate ancestry inference into routine diagnostic workflows. We show that global ancestral contributions and admixture of continental populations can be quantitatively inferred using markers captured by the MSK-IMPACT clinical panel. In a pan-cancer cohort of 45,157 patients, we observed differences by ancestry in the frequency of somatic alterations, recapitulating known associations and revealing novel associations. Despite the comparable overall prevalence of driver alterations by ancestry group, the proportion of patients with clinically actionable alterations was lower for African (30%) compared with European (33%) ancestry. Although this result is largely explained by population-specific cancer subtype differences, it reveals an inequity in the degree to which different populations are served by existing precision oncology interventions.Significance:We performed a comprehensive analysis of ancestral associations with somatic mutations in a real-world pan-cancer cohort, including >5,000 non-European individuals. Using an FDA-authorized tumor sequencing panel and an FDA-recognized oncology knowledge base, we detected differences in the prevalence of clinically actionable alterations, potentially contributing to health care disparities affecting underrepresented populations.This article is highlighted in the In This Issue feature, p. 2483

Supplementary Data from Genetic Ancestry Correlates with Somatic Differences in a Real-World Clinical Cancer Sequencing Cohort

Supplementary Table 1 shows the adverse events suspected to be study drug-related. Supplementary Table 2 shows the sequencing data availability by treatment group. Supplementary Table 3 shows the observed correlations between selected mutations/alterations. Supplementary Figure 1 shows the time on study for each patient. Supplementary Figure 2 shows the gene alterations ordered by chromosome and PFS. Supplementary Figure 3 shows gene alterations ordered by chromosome and percentage change from baseline. Supplementary Figure 4 shows Kaplan-Meier plot of PFS for patients with or without a GNAQ mutation.

Up to 50% of patients with uveal melanoma (UM) develop metastatic disease, for which there is no effective systemic treatment. This study aimed to evaluate the safety and efficacy of the orally available protein kinase C inhibitor, AEB071, in patients with metastatic UM, and to perform genomic profiling of metastatic tumor samples, with the aim to propose combination therapies. Patients with metastatic UM (n = 153) were treated with AEB071 in a phase I, single-arm study. Patients received total daily doses of AEB071 ranging from 450 to 1,400 mg. First-cycle dose-limiting toxicities were observed in 13 patients (13%). These were most commonly gastrointestinal system toxicities and were dose related, occurring at doses ≥700 mg/day. Preliminary clinical activity was observed, with 3% of patients achieving a partial response and 50% with stable disease (median duration 15 weeks). High-depth, targeted next-generation DNA sequencing was performed on 89 metastatic tumor biopsy samples. Mutations previously identified in UM were observed, including mutations in GNAQ, GNA11, BAP1, SF3B1, PLCB4, and amplification of chromosome arm 8q. GNAQ/GNA11 mutations were observed at a similar frequency (93%) as previously reported, confirming a therapeutic window for inhibition of the downstream effector PKC in metastatic UM.In conclusion, the protein kinase C inhibitor AEB071 was well tolerated, and modest clinical activity was observed in metastatic UM. The genomic findings were consistent with previous reports in primary UM. Together, our data allow envisaging combination therapies of protein kinase C inhibitors with other compounds in metastatic UM.

PDF file - 470KB, All supplementary figures including tumor histology, RAD50 immunohistochemistry, candidate mutations and their clonality, and supporting yeast and MEF experimental data.

PDF file - 2461KB, A complete listing of somatic mutations and rearrangements detected as well as targeted genes, sequences, MRN complex mutation frequency, and strains utilized.

PDF file - 321KB, A detailed description of additional methods utilized (and associated references) for sequencing and analysis as well as an explanatory note regarding the TM pathway in yeast.

Table S2. Oncogenic/Likely-oncogenic structural variants in GBC

Purpose:Gallbladder carcinoma (GBC) is an uncommon and aggressive disease, which remains poorly defined at a molecular level. Here, we aimed to characterize the molecular landscape of GBC and identify markers with potential prognostic and therapeutic implications.Experimental Design:GBC samples were analyzed using the MSK-IMPACT (Memorial Sloan Kettering–Integrated Mutation Profiling of Actionable Cancer Targets) platform (targeted NGS assay that analyzes 505 cancer-associated genes). Variants with therapeutic implications were identified using OncoKB database. The associations between recurrent genetic alterations and clinicopathologic characteristics (Fisher exact tests) or overall survival (univariate Cox regression) were evaluated. P values were adjusted for multiple testing.Results:Overall, 244 samples (57% primary tumors and 43% metastases) from 233 patients were studied (85% adenocarcinomas, 10% carcinomas with squamous differentiation, and 5% neuroendocrine carcinomas). The most common oncogenic molecular alterations appeared in the cell cycle (TP53 63% and CDKN2A 21%) and RTK_RAS pathways (ERBB2 15% and KRAS 11%). No recurrent structural variants were identified. There were no differences in the molecular landscape of primary and metastasis samples. Variants in SMAD4 and STK11 independently associated with reduced survival in patients with metastatic disease. Alterations considered clinically actionable in GBC or other solid tumor types (e.g., NTRK1 fusions or oncogenic variants in ERBB2, PIK3CA, or BRCA1/2) were identified in 35% of patients; 18% of patients with metastatic disease were treated off-label or enrolled in a clinical trial based on molecular findings.Conclusions:GBC is a genetically diverse malignancy. This large-scale genomic analysis revealed alterations with potential prognostic and therapeutic implications and provides guidance for the development of targeted therapies.

Figure S1. Mutation signatures and altered canonical pathways in GBC.

Table S3. Therapy regimens

Table S1. Sample list (cBioPortal identifiers, ‘DMP_SAMPLE_ID’). Only the primary tumor (if available) or the earliest collected metastasis are included (n=233)

Detailed statistical results

PDF file - 3248K, Supplementary Table S1. Histopathologic findings for multi-region analysis. Supplementary Table S2.IMPACT gene list and their respective chromosomal positions. Supplementary Table S5. WEC run statistics on patients #4 and #5. Supplementary Table S6.List of all non-variant mutations detected by IMPACT assays in individual patient samples. Supplementary Table S7. Non-variant mutations identified by WEC in patients #4 and #5. Supplementary Figure 1. Flow chart depicts the IMPACT assay mutation identification and filtering algorithm. Supplementary Figure 2. Flow chart depicts the WEC assay mutation identification and filtering algorithm. Supplementary Figure 3. Sanger validations of mutations in the targeted pathway indentified by IMPACT assay for R1 of patients #1,#2, and #3. Supplementary Figure 4. Sanger validations of mutations in the targeted pathway indentified by IMPACT assay for additional regions analyzed for patients #1, and #3. Supplementary Figure 5. The Q2223K mTOR mutation provokes hyperactivation of mTORC1 in serum free growth conditions. Supplementary Figure 6. Hyperactivation of mTORC1 induced by Q2223K is sensitive to rapalog-based mTOR inhibition. Supplementary Figure 7. Immunoblots detecting phosphorylated mTOR at serine residues 2448 (S2448) and 2481 (S2481). Supplementary Figure 8. Copy number plots for multiple tumor regions in patient #3 showing the loss of chromosome 9 only in tumor regions carrying the TSC1 nonsense mutation (R3, R4). Supplementary Figure 9. Copy number plots for patient with tuberous sclerosis complex and metastatic unclassified RCC with extended benefit from everolimus therapy (44+ months). Supplementary Figure 10. PI3K pathway alterations as reported across 418 cases of clear cell RCC in TCGA. Alterations are detected in 42% of cases. Supplementary Figure 11: Hematoxylin and eosin (H&E) stains and immunohistochemistry for 4EBP1 phosphorylation (Thr 37/46), an mTORC1 downstream effector, in primary kidney tumors and adjacent normal kidney tissue for patients 1-5.

Purpose: Rapalogs are allosteric mTOR inhibitors and approved agents for advanced kidney cancer. Reports of clonal heterogeneity in this disease challenge the concept of targeted monotherapy, yet a small subset of patients derives extended benefit. Our aim was to analyze such outliers and explore the genomic background of extreme rapalog sensitivity in the context of intratumor heterogeneity.Experimental Design: We analyzed archived tumor tissue of 5 patients with renal cell carcinoma, who previously achieved durable disease control with rapalogs (median duration, 28 months). DNA was extracted from spatially separate areas of primary tumors and metastases. Custom target capture and ultradeep sequencing was used to identify alterations across 230 target genes. Whole-exome sequence analysis was added to investigate genes beyond this original target list.Results: Five long-term responders contributed 14 specimens to explore clonal heterogeneity. Genomic alterations with activating effect on mTOR signaling were detected in 11 of 14 specimens, offering plausible explanation for exceptional treatment response through alterations in two genes (TSC1 and MTOR). In two subjects, distinct yet functionally convergent alterations activated the mTOR pathway in spatially separate sites. In 1 patient, concurrent genomic events occurred in two separate pathway components across different tumor regions.Conclusions: Analysis of outlier cases can facilitate identification of potential biomarkers for targeted agents, and we implicate two genes as candidates for further study in this class of drugs. The previously reported phenomenon of clonal convergence can occur within a targetable pathway which might have implications for biomarker development beyond this disease and this class of agents. Clin Cancer Res; 20(7); 1955–64. ©2014 AACR.

Supplementary Figures S1-S6, Table S1-S3, and eMethods

Purpose:MET tyrosine kinase inhibitors (TKIs) can achieve modest clinical outcomes in MET exon 14–altered lung cancers, likely secondary to primary resistance. Mechanisms of primary resistance remain poorly characterized and comprehensive proteomic analyses have not previously been performed.Experimental Design:We performed hybrid capture-based DNA sequencing, targeted RNA sequencing, cell-free DNA sequencing, selected reaction monitoring mass spectrometry (SRM-MS), and immunohistochemistry on patient samples of MET exon 14–altered lung cancers treated with a MET TKI. Associations between overall response rate (ORR), progression-free survival (PFS), and putative genomic alterations and MET protein expression were evaluated.Results:Seventy-five of 168 MET exon 14–altered lung cancers received a MET TKI. Previously undescribed (zygosity, clonality, whole-genome duplication) and known (copy-number focality, tumor mutational burden, mutation region/type) genomic factors were not associated with ORR/PFS (P > 0.05). In contrast, MET expression was associated with MET TKI benefit. Only cases with detectable MET expression by SRM-MS (N = 15) or immunochemistry (N = 22) responded to MET TKI therapy, and cancers with H-score ≥ 200 had a higher PFS than cancers below this cutoff (10.4 vs. 5.5 months, respectively; HR, 3.87; P = 0.02).Conclusions:In MET exon 14–altered cancers treated with a MET TKI, a comprehensive analysis of previously unknown and known genomic factors did not identify a genomic mechanism of primary resistance. Instead, MET expression correlated with benefit, suggesting the potential role of interrogating the proteome in addition to the genome in confirmatory prospective trials.

XLSX file - 13K, Supplementary Table S3. Impact assay run statistics on all samples.

PDF file - 132K

To investigate the presence of plasma circulating tumor DNA (ctDNA) in patients with uveal melanoma during and after primary tumor treatment.Detectability and variant allele frequency of ctDNA were assessed using a 129-oncogene panel using next-generation deep sequencing and hybridization capture in 69 patients with uveal melanoma undergoing primary treatment with enucleation (n = 8, during surgery) or plaque brachytherapy (n = 61; postoperative day 0, 1, 2, or 3). Follow-up assessments were performed in 39 patients over a median of 21 months (range, 3.2-31.9 months) of follow-up. Correlations between genomic data and disease parameters were performed.Overall, ctDNA was detectable in 20 of 69 patients with uveal melanoma (28.9%) during the perioperative period. On the day of enucleation, ctDNA was detected in two of eight patients (25%). In patients undergoing brachytherapy, ctDNA was significantly more detectable on postoperative days 2 or 3 compared with postoperative day 0 or 1 (32.4% vs 0.0%; P = 0.0015). Patients with follow-up ctDNA that became detectable or had an increased variant allele frequency were significantly more likely to develop metastasis compared with patients with follow-up ctDNA that became undetectable or decreased variant allele frequency (P = 0.04). In patients with detectable vs. undetectable ctDNA, there was no significant difference in tumor size, stage or location.ctDNA is significantly more detectable at 48 to 72 hours after plaque brachytherapy compared with less than 48 hours. ctDNA can be detected during enucleation. Relative increases in ctDNA levels may herald the development of clinically apparent metastases.

Purpose: Gallbladder carcinoma (GBC) is an uncommon and aggressive disease, which remains poorly defined at a molecular level. Here, we aimed to characterize the molecular landscape of GBC and identify markers with potential prognostic and therapeutic implications. Experimental Design: GBC samples were analyzed using the MSK-IMPACT (Memorial Sloan Kettering–Integrated Mutation Profiling of Actionable Cancer Targets) platform (targeted NGS assay that analyzes 505 cancer-associated genes). Variants with therapeutic implications were identified using OncoKB database. The associations between recurrent genetic alterations and clinicopathologic characteristics (Fisher exact tests) or overall survival (univariate Cox regression) were evaluated. P values were adjusted for multiple testing. Results: Overall, 244 samples (57% primary tumors and 43% metastases) from 233 patients were studied (85% adenocarcinomas, 10% carcinomas with squamous differentiation, and 5% neuroendocrine carcinomas). The most common oncogenic molecular alterations appeared in the cell cycle (TP53 63% and CDKN2A 21%) and RTK_RAS pathways (ERBB2 15% and KRAS 11%). No recurrent structural variants were identified. There were no differences in the molecular landscape of primary and metastasis samples. Variants in SMAD4 and STK11 independently associated with reduced survival in patients with metastatic disease. Alterations considered clinically actionable in GBC or other solid tumor types (e.g., NTRK1 fusions or oncogenic variants in ERBB2, PIK3CA, or BRCA1/2) were identified in 35% of patients; 18% of patients with metastatic disease were treated off-label or enrolled in a clinical trial based on molecular findings. Conclusions: GBC is a genetically diverse malignancy. This large-scale genomic analysis revealed alterations with potential prognostic and therapeutic implications and provides guidance for the development of targeted therapies.

Purpose: MET tyrosine kinase inhibitors (TKIs) can achieve modest clinical outcomes in MET exon 14–altered lung cancers, likely secondary to primary resistance. Mechanisms of primary resistance remain poorly characterized and comprehensive proteomic analyses have not previously been performed. Experimental Design: We performed hybrid capture-based DNA sequencing, targeted RNA sequencing, cell-free DNA sequencing, selected reaction monitoring mass spectrometry (SRM-MS), and immunohistochemistry on patient samples of MET exon 14–altered lung cancers treated with a MET TKI. Associations between overall response rate (ORR), progression-free survival (PFS), and putative genomic alterations and MET protein expression were evaluated. Results: Seventy-five of 168 MET exon 14–altered lung cancers received a MET TKI. Previously undescribed (zygosity, clonality, whole-genome duplication) and known (copy-number focality, tumor mutational burden, mutation region/type) genomic factors were not associated with ORR/PFS (P > 0.05). In contrast, MET expression was associated with MET TKI benefit. Only cases with detectable MET expression by SRM-MS (N = 15) or immunochemistry (N = 22) responded to MET TKI therapy, and cancers with H-score ≥ 200 had a higher PFS than cancers below this cutoff (10.4 vs. 5.5 months, respectively; HR, 3.87; P = 0.02). Conclusions: In MET exon 14–altered cancers treated with a MET TKI, a comprehensive analysis of previously unknown and known genomic factors did not identify a genomic mechanism of primary resistance. Instead, MET expression correlated with benefit, suggesting the potential role of interrogating the proteome in addition to the genome in confirmatory prospective trials.

OncoKB, Memorial Sloan Kettering Cancer Center’s (MSK) precision oncology knowledge base (www.oncokb.org), is an FDA-recognized* somatic variant database that contains information about the oncogenic effect and clinical implications of genomic alterations in cancer. Since its 2016 public release, OncoKB has grown to include annotation for >5,770 alterations in ~700 cancer-associated genes. OncoKB data is integrated into the cBioPortal for Cancer Genomics and used to annotate >12,000 MSK patient sequencing reports annually, encompassing both solid tumor and hematological malignancies. Users in academic, commercial and hospital settings outside MSK can programmatically access OncoKB data via its web API with an OncoKB license, which is free for academic research. To date, users from ~ 1400 institutions across >70 countries have licensed access to OncoKB annotations. The OncoKB Therapeutic (Tx) Levels of Evidence assign tumor-type specific clinical actionability to individual mutational events based on data supporting whether an alteration is predictive of response to matched targeted therapies. To date, OncoKB includes 44 Level 1 genes (included in the FDA drug label), 23 Level 2 genes (included in professional guidelines), 33 Level 3A genes (predictive of drug response in well-powered clinical studies), 27 Level 4 genes (predictive of drug response based on compelling biological evidence), and 11 R1/R2 resistance genes. In 2022, several major content additions were made to OncoKB based on key shifts in the precision oncology landscape. For example, OncoKB included 2 new tumor-agnostic FDA drug approvals, dabrafenib + trametinib and selpercatinib for BRAF V600E and RET fusion-positive solid tumors respectively (Level 1), capturing 5 tumor-agnostic FDA drug approvals to date. OncoKB promoted ERBB2 oncogenic mutations and FGFR1 fusions to Level 1 following their inclusion as patient eligibility criteria in FDA drug labels for trastuzumab deruxtecan (NSCLC) and pemigatinib (myeloid/lymphoid neoplasms) respectively. NCCN guidelines for uterine sarcoma and pancreatic cancer listed PARP-inhibition for BRCA-mutant disease, making them Level 2 in these indications. Lastly, previously considered undruggable targets, TP53 Y220C and KRAS G12D, were included in OncoKB based on compelling evidence demonstrating response to allele-targeting drugs, PC14586 and RMC-6263, respectively. In sum, 7 novel clinically actionable biomarkers (Levels 1-4) and 11 follow-on precision oncology therapies for existing leveled biomarkers were added to OncoKB in 2022. Current OncoKB efforts are focused on prioritized high-volume cancer gene curation for annotation of whole exome/genome data, annotation of germline alterations and development of a clinical trials matching system. *FDA recognition of OncoKB is partial and limited to the information clearly marked on www.oncokb.org. Citation Format: Sarah P. Suehnholz, Moriah Nissan, Hongxin Zhang, Ritika Kundra, Calvin Lu, Amanda Dhaneshwar, Nicole Fernandez, Stephanie Carrero, Maria E. Arcila, Marc Ladanyi, Michael F. Berger, Aijazuddin Syed, Rose Brannon, Ross Levine, Ahmet Dogan, Ezra Rosen, Alexander Drilon, David B. Solit, Nikolaus Schultz, Debyani Chakravarty. OncoKB, MSK’s precision oncology knowledge base. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6585.

Introduction: The MYC gene family (MYCf), which includes MYC, MYCN, and MYCL, is deregulated in ~70% of cancers and is associated with treatment resistance. Whereas older investigational therapies for MYC amplified tumors were unsuccessful, promising novel targeted therapies are in early phase clinical trials. Unfortunately, it remains unclear how to select patients whose cancers may harbor true MYC addiction. We thus sought to characterize factors such as amplification level, focality, and clonality that may correlate with increased MYC dependence. Methods: Utilizing a center-wide next generation sequencing (NGS) program of >71,000 sequenced patients, genomic and clinical data from pediatric and adult patients with MYC, MYCN, and MYCL amplifications were identified between 2014 and 2022. Patients were characterized as harboring MYC, MYCN, and MYCL amplification based on a read-depth methodology using a DNA-based hybrid-capture NGS (MSK-IMPACT) and Fraction and Allele-Specific Copy Number Estimates from the Tumor Sequencing (FACETS). All cases underwent clinical data curation including baseline demographic, tumor characteristics, and treatment histories. Results: We identified 3911 cancers with MYCf amplification (n=3257 (82%) MYC; n=364 (9%) MYCL; n=330 (8%) MYCN) across 40 malignancies, for an overall 5.5% incidence. The most frequent tumor types with MYCf amplification were breast (22%), non-small cell lung (NSCLC) (11%), colorectal (8%), ovarian (8%), prostate (7%), brain (5%), and small cell lung cancers (SCLC) (2%). Cancers with MYC amplification had longer segment lengths than MYCL and MYCN amplification, which appeared more focal (median = 19, 4.3 and 4.5 MB, respectively, p < 0.001). MYCN amplified cancers had higher total copy number than MYC and MYCL amplified cancers (median = 19, 8, 9, respectively, p < 0.001). MYC, MYCN, and MYCL samples were predominantly clonal (median clonal fraction > 99% for all genes). Most NSCLC, squamous cell lung cancers, and pulmonary carcinoids had MYC amplifications (93%, 70%, and 67% respectively). Conversely, SCLCs most often had MYCL amplifications (49%). No concurrent targetable driver alterations were found in 33% of metastatic NSCLCs with MYC, 75% of MYCN, and 6% of MYCL amplifications. Conclusions: While MYCf amplification is observed across a broad range of cancer types, factors such as gene type (MYC, MYCN, MYCL), focality, total copy number, clonality, and concurrent oncogenic drivers vary widely. Novel MYC-directed trials may consider enrichment for a subpopulation of cancers with higher-level, focal, and clonal MYCf amplifications without concurrent other drivers. Citation Format: Monica F. Chen, Allison Richards, Patrick Evans, Patrick Lee, Adam Price, Matteo Repetto, Soo Ryum Yang, Jason Chang, Rose Brannon, Ezra Rosen, David Brown, Charles Rudin, Nitya Raj, Mark G. Kris, Jorge Reis-Filho, Mark Donoghue, Alexander E. Drilon, Noura J. Choudhury. Comprehensive clinical and genomic analysis for patients with MYC, MYCN, and MYCL amplified solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1394.

Large case-control and familial studies have established clear cancer-specific risk profiles for several key cancer predisposition genes (CPGs). For example, germline pathogenic variants (PVs) in BRCA1/2 (gBRCA) are associated with increased risk for developing breast, ovarian, pancreatic, and prostate cancers. However, the extent to which gBRCA mutations are involved in mediating the tumorigenesis of other cancer types remains challenging to characterize. We hypothesized that integrating orthogonal features such as selection for biallelic inactivation of the PVs and depletion of canonical somatic drivers among the carriers can enrich the signal for identifying novel gene and cancer type associations. We then extend this framework to identify novel CPGs as well as to understand how tumors arise in patients with PVs in oncogenes. To study this, we leveraged the prospective MSK-IMPACT matched tumor-normal sequencing cohort of 49,291 patients across 77 major cancer types. We study 90 well-known CPGs as well as >300 cancer genes not previously associated with cancer predisposition. Overall, 8% (N=3,964) of patients harbored a PV in high or moderate penetrance CPGs. We identified 90 gene and cancer type associations with enrichment for biallelic inactivation (q Among carriers of PVs in oncogenes, we observe two possible mechanisms of first somatic hit towards malignant transformation. We find enrichment for copy number gain or copy neutral loss of heterozygosity of the germline PV in thyroid cancers with a PV in RET. We also find that lung cancers with a germline PV in EGFR frequently developed additional somatic point mutations located in cis with the PV. Investigating genes with no prior association with germline predisposition to cancer, we find evidence for KEAP1 and CIC as likely novel CPGs. Lung (n=8) and thyroid (n=4) cancers with deleterious germline variants in KEAP1 were characterized by loss of the wild-type allele, co-occurring somatic STK11 mutations, and depletion of canonical drivers such as EGFR. We also found biallelic loss of CIC in two patients with Neuroblastoma, each carrying a different germline loss-of-function mutation in CIC. Both tumors were also negative for MYCN and ALK defects. Collectively, our findings expand our understanding of cancer predisposition in cancer, shed new insights into how tumors arise in germline carriers, and provide a framework for identifying new CPGs using population scale tumor-normal paired clinical sequencing data. Citation Format: Miika Mehine, Rebecca Caeser, Yelena Kemel, Daniel Muldoon, Sebastià Franch-Expósito, A. Rose Brannon, Aijazuddin Syed, Ozge Ceyhan-Birsoy, Maksym Misyura, Panieh Terraf, David B. Solit, Marc Ladanyi, Kenneth Offit, Zsofia K. Stadler, Diana L. Mandelker, Yonina R. Murciano-Goroff, Charles M. Rudin, Michael F. Berger, Chaitanya Bandlamudi. Expanding the spectrum of germline-driven cancers by leveraging population-scale targeted tumor and normal sequencing. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5214.

Intro: High-Grade Gliomas (HGGs) are the most common and aggressive primary brain tumors in adults and are almost always fatal. Liquid biopsy provides a noninvasive window into the cancer genome and the underlying biology of the tumor. Circulating-tumor DNA (ctDNA) is a versatile analyte for tumor diagnosis, monitoring treatment response, detecting resistance, and tracking tumor evolution. The central hypothesis of our work is that detection of cerebrospinal fluid (CSF) ctDNA correlates with clinically significant events and can be used as a surrogate for tissue biopsy to guide treatment decisions in the clinic. Methods: Our study includes CSF ctDNA samples from 140 recurrent glioma patients at Memorial Sloan Kettering Cancer Center who underwent collection of CSF as part of their clinical evaluation for neurological signs and symptoms. For each patient, glioma subtype and grade were confirmed by a neuropathologist. Overall survival was calculated as the time interval between the date of diagnosis and the date of death. All samples were sequenced using the MSK-IMPACT targeted sequencing assay (468 genes). Allele-specific copy number calls were assessed using the FACETS algorithm. Mutations were classified as drivers based on OncoKB. To evaluate the relationship between CSF ctDNA detection and clinico-pathologic correlates, CSF ctDNA status was determined positive by the presence of at least one somatic mutation and CSF ctDNA status was correlated with clinico-pathologic features. Results: Within this cohort, we found 68 CSF ctDNA positive and 72 CSF negative samples. The most frequently mutated genes were: TERT (58.2%), TP53 (47.8%), IDH1 (20.9%) and EGFR (26.9%). We observed a concordance between contemporaneously sampled tumor and CSF. In a multivariate analysis accounting for established prognostic factors including: % extent of resection at diagnosis; tumor burden at the time of lumbar puncture; and IDH status, we found that CSF ctDNA positivity was negatively correlated with overall survival (HR: 2.52, p Conclusion: ctDNA from CSF depicts a powerful analyte with the potential to alter the standard of care. We have established a robust liquid biopsy program across the neuro-oncology department at MSK, and MSK-IMPACT is now certified by NYS DOH for use on CSF ctDNA enabling routine integration into clinical care. In summary, we are now able to monitor the changing genome along the disease course and have the potential to detect disease occurrence at an earlier time point, however further validation of CSF ctDNA for disease monitoring is needed. Additionally, our data suggests that CSF ctDNA may be used as a prognostic biomarker for survival, but confirmation requires further validation in a prospective study. Citation Format: Subhiksha Nandakumar, Christoph Kreitzer, Charli Ann Hertz, Johnathan Rafailov, Timothy Song, Nicholas D. Socci, A. Rose Brannon, Maria E. Arcila, David B. Solit, Michael F. Berger, Nikolaus Schultz, Ingo K. Mellinghoff, Alexandra M. Miller. Circulating tumor DNA from cerebrospinal fluid (CSF) allows for characterization and monitoring of glioma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1053.

Circulating tumor DNA (ctDNA) sequencing guides therapy decisions but has been studied mostly in small cohorts without sufficient follow-up to determine its influence on overall survival. We prospectively followed an international cohort of 1,127 patients with non-small-cell lung cancer and ctDNA-guided therapy. ctDNA detection was associated with shorter survival (hazard ratio (HR), 2.05; 95% confidence interval (CI), 1.74-2.42; P 0.001) independently of clinicopathologic features and metabolic tumor volume. Among the 722 (64%) patients with detectable ctDNA, 255 (23%) matched to targeted therapy by ctDNA sequencing had longer survival than those not treated with targeted therapy (HR, 0.63; 95% CI, 0.52-0.76; P 0.001). Genomic alterations in ctDNA not detected by time-matched tissue sequencing were found in 25% of the patients. These ctDNA-only alterations disproportionately featured subclonal drivers of resistance, including RICTOR and PIK3CA alterations, and were associated with short survival. Minimally invasive ctDNA profiling can identify heterogeneous drivers not captured in tissue sequencing and expand community access to life-prolonging therapy.

Background: Cancer survivors are developing more subsequent tumors. We sought to characterize patients with multiple (≥2) primary cancers (MPC) to assess associations and genetic mechanisms. Methods: Patients were prospectively consented (01/2013–02/2019) to tumor-normal sequencing via a custom targeted panel (MSK-IMPACT). A subset consented to return of results of ≥76 cancer predisposition genes. International Agency for Research on Cancer (IARC) 2004 rules for defining MPC were applied. Tumor pairs were created to assess relationships between cancers. Age-adjusted, sex-specific, standardized incidence ratios (SIR) for first to second cancer event combinations were calculated using SEER rates, adjusting for confounders and time of ascertainment. Associations were made with germline and somatic variants. Results: Of 24,241 patients, 4,340 had MPC (18%); 20% were synchronous. Most (80%) had two primaries; however, 4% had ≥4 cancers. SIR analysis found lymphoma–lung, lymphoma–uterine, breast–brain, and melanoma–lung pairs in women and prostate–mesothelioma, prostate–sarcoma, melanoma–stomach, and prostate–brain pairs in men in excess of expected after accounting for synchronous tumors, known inherited cancer syndromes, and environmental exposures. Of 1,580 (36%) patients who received germline results, 324 (21%) had 361 pathogenic/likely pathogenic variants (PV), 159 (44%) in high penetrance genes. Of tumor samples analyzed, 55% exhibited loss of heterozygosity at the germline variant. In those with negative germline findings, melanoma, prostate, and breast cancers were common. Conclusions: We identified tumor pairs without known predisposing mutations that merit confirmation and will require novel strategies to elucidate genetic mechanisms of shared susceptibilities. Impact: If verified, patients with MPC with novel phenotypes may benefit from targeted cancer surveillance.

Purpose Analysis of circulating tumor DNA (ctDNA) in the plasma of patients with retinoblastoma and simulating lesions. Design Retrospective cross-sectional study of the association of plasma ctDNA from retinoblastoma and simulating lesions with disease course. Participants Fifty-eight Memorial Sloan Kettering Cancer Center patients with retinoblastoma comprising 68 plasma ctDNA samples and 5 with retinoblastoma-simulating lesions. Methods The ctDNA analyzed with hybridization capture and next-generation sequencing in blood (plasma) of patients who had retinoblastoma or simulating lesions were evaluated for association with clinical course of the disease. Main Outcome Measures Presence or absence of molecular aberrations in the RB1 gene and correlations with clinical features. Results RB1 cell-free DNA (cfDNA) was detected in 16 of 19 patients with newly diagnosed, untreated intraocular retinoblastoma and in 3 of 3 patients with newly diagnosed, untreated metastatic disease. It was also present in 3 patients with recurrent intraocular disease before therapy, but was not present in patients with recurrent disease who received intra-arterial chemotherapy, nor in 21 patients who had undergone enucleation for unilateral disease. In 1 patient who had delayed treatment (insurance reasons) and showed rapid growth of the intraocular tumor, the variant allele frequency increased in 1 month from 0.34% to 2.48%. No RB1 mutations were detected in the cfDNA from plasma of patients with simulating lesions (3 with Coats disease and 1 with persistent fetal vasculature [PFV]). In 2 patients, we identified 2 independent RB1 mutations in plasma. Conclusions Mutations in RB1 were found in the cfDNA from blood of patients with newly diagnosed, untreated retinoblastoma and in patients who showed disease recurrence in the eye after prior treatment, but not in unilateral retinoblastoma after enucleation Levels of ctDNA increase in patients with progressive disease who did not receive any treatment. High plasma cfDNA levels were detected in patients with newly diagnosed metastatic disease, and these levels decreased after systemic chemotherapy was administered. Further validation is needed for measuring the somatic alterations in cfDNA from blood in retinoblastoma that could provide a promising method of monitoring patients in the future.

Background: The fibroblast growth factor receptor (FGFR) inhibitor erda is the only FDA-approved targeted treatment (tx) for mUC with FGFR2/3 alterations (alt). Median progression-free survival on erda is 5.5 months and mechanisms of resistance remain poorly characterized. Analysis of ctDNA offers an opportunity to longitudinally and non-invasively assess for mechanisms of resistance. Methods: Plasma was collected from mUC pts on erda at baseline, on-tx, and at disease progression (PD). Clinical characteristics were recorded. Pre-tx tumors were sequenced with MSK-IMPACT and plasma samples with MSK-ACCESS, a cell-free DNA assay sequencing 129 genes with unique molecular indexes to generate >15,000x coverage for detection of mutations to an allele frequency of 0.1%. Results: Between 8/2019-9/2021, 18 pts received erda. Median progression-free survival was 4.2 months, range 1.4-10.8. Tx was discontinued in 14 pts for PD, 3 for toxicity, and 1 death unrelated to erda/PD. During tx, several pts acquired new alts in ctDNA compared to pre-tx tumor/ctDNA, most commonly in TP53 (n = 5) and FGFR3 (n = 4) (Table 1). Of 9 newly acquired FGFR2/3 alts observed in ctDNA on-tx, 3 were hotspots. Several acquired FGFR3 alts have been shown to impact binding of erda to FGFR3 in vitro (Table 1). Of 5 pts with primary refractoriness to erda, 3 had baseline activating alts of signaling downstream or parallel to FGFR, including alts of PIK3CA (n = 1), TSC1 (n = 1), and HER2 (n = 2). Of 3 pts with TP53 alts in baseline ctDNA, 2 had PD as best response to erda. Conclusions: Pts with mUC treated with erda demonstrated on-tx acquisition of ctDNA alts of FGFR2/3 and TP53 and activating alts downstream or parallel to FGFR signaling. Most pts with TP53 alts in baseline ctDNA were refractory to erda. Acquired FGFR2/3 alts on erda may drive resistance through interference with drug-target binding. Case # Pre-tx FGFR2/3 alts Alts acquired on erda related to TP53 and FGFR signaling 1 FGFR3 Y373C TP53 K132M; TP53 R158L 2 FGFR3 S371C; FGFR3 R399C; FGFR3 R248C; FGFR3 S249C; FGFR3-TACC3 fusion FGFR3 R669G&; FGFR3 V553M&; FGFR3 N540S&; FGFR3 H673Y; FGFR3 K649_K650delinsIE; TP53 S241C; BRAF-CLIP2 fusion 3 FGFR3 S249C TP53 E287Q 4 FGFR3 S249C FGFR3 V553M&; FGFR3 K650M; FGFR2 R255W; AKT1 E17K 5 FGFR3 S249C FGFR3 R248C 6 FGFR3 S249C TP53 I195T 7 FGFR3 Y373C TP53 R248W; TP53 S241Y 8 FGFR3 S249C; FGFR3 L645V FGFR3 S424C & Alts likely to impact erda binding to FGFR3. Citation Format: Brendan J. Guercio, Michal Sarfaty, Min Yuen Teo, Samuel A. Funt, Chung-Han Lee, David H. Aggen, Neha Ratna, Ashley M. Regazzi, Ziyu Chen, Michael Lattanzi, Hikmat A. Al-Ahmadie, A. Rose Brannon, Michael F. Berger, David B. Solit, Jonathan E. Rosenberg, Dean F. Bajorin, Gopa Iyer. Identifying potential mechanisms of resistance to erdafitinib (erda) via longitudinal analysis of circulating tumor (ct)-DNA of patients (pts) with advanced/metastatic urothelial cancer (mUC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3410.

Introduction: Gallbladder carcinomas (GBC) are rare and aggressive neoplasms. Previous studies in small GBC cohorts have suggested potential molecular alterations associated with poor prognosis, however, a comprehensive understanding of the recurrent genetic events in this cancer type is very limited. In this study, we aim to characterize in detail the recurrent molecular alterations in GBC and their association with pathologic and clinical characteristics. Material and Methods: We studied the prevalence of somatic mutations and copy number alterations (CNA) in n=244 GBC samples (54% primary, 56% metastatic), collected from 2014 to 2021, and sequenced with the targeted NGS panel MSK-IMPACT. We assessed the correlation of the recurrent genomic variants with several pathologic (e.g., T stage, N stage, grade, histologic subtypes) and clinical characteristics (e.g., clinical stage) using Fisher's exact test. We also used Cox Proportional-Hazards modeling to assess the correlation between genetic variants and patient overall survival (OS). Results: The most common histologic subtypes in this GCB cohort included adenocarcinomas NOS (83%), carcinomas with squamous differentiation (9%), high-grade carcinomas (4%), and carcinomas with neuroendocrine differentiation (3%). Most patients were diagnosed with stage IV (65%) and stage III (11%) disease at the time of biopsy/resection, and the mean OS survival was 29.4 months. The most commonly mutated genes were TP53 (59%), SMAD4 (21%), ARID1A (19%), PIK3CA (10%), KRAS (7%), and ERBB2 (7%). Potentially recurrent oncogenic CNAs included deep deletions in CDKN2A (14%) and CDKN2B (14%), and amplifications in MDM2 (12%), ERBB2 (10%), CCNE1 (9%), MYC (7%), and KRAS (7%). RB1, PBRM1, and CTNNB1 variants were more common in cases with neuroendocrine differentiation, whereas alterations in IKZF1 and AGO2 were enriched in cases with squamous differentiation. The most significant event associated with shorted OS was chromosome 12q13-15 amplification i.e., CDK4 p=0.03 HR=2 [95% CI 1-3.6] and MDM2 p=0.05 HR=1.6 [1-2.5], which associated with a median OS of 20 months (vs. 34 months in the wild-type). Genomic variants associated with longer OS included ERBB2 (p=0.006 HR=0.2 [0.06-0.6]), KMT2C (p=0.03 HR=0.2 [0.1-0.9]) and KMT2D (p=0.01 HR=0.2 [0.04-0.7]) mutations, and CDK12 amplification (p=0.04 HR=0.4 [0.2-0.96]). Although ERBB2 amplification was not associated with prognosis, co-amplification of CDK12 and ERBB2 (chromosome 17q12) was frequently observed (Pearson correlation r=0.8). Conclusions: This large-scale genomic analysis reveals recurrent genomic events potentially associated with prognosis in GBC, including single nucleotide variants in ERBB2, KMT2C, and KMT2D, in addition to CNAs in chromosome 12q13-15 and 17q12 regions. This effort will continue to include a detailed analysis of recurrent structural variants, loss of heterozygosity loci, and analysis of the microbiota in this GBC cohort. Citation Format: Nicolas A. Giraldo, Abhinita Mohanty, Chad Vanderbilt, Rose Brannon, Ryma Benayed, Efsevia Vakiani, Ghassan Abou-Alfa, James Harding, Imane El Dika, Nikolaus Schultz, Bob Li, Michael F. Berger, Marc Ladanyi, Eileen O'Reilly, William Jarnagin, Olca Basturk, Maria Arcila. Molecular characterization of gallbladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 82.