Genomic landscape of circulating tumor DNA and real-world outcomes in advanced endometrial cancer.

PURPOSE: ctDNA is a novel technique extensively studied in solid tumors, although not currently well defined in endometrial cancer (EC). EXPERIMENTAL DESIGN: A de-identified retrospective analysis of 1988 patients with advanced/recurrent EC was performed. In addition, an analysis of a real-world evidence (RWE) cohort was completed (n=1266). Patients underwent ctDNA testing using Guardant360 during routine clinical care. The objective was to describe and assess molecular landscape using ctDNA. RESULTS: Among 1988 ctDNA samples, at least one somatic alteration was detected in 91.6% (n=1821). Most frequently altered genes were TP53 (64%), PIK3CA (29%), PTEN (25%), ARID1A (20%) and KRAS (14%). Overall, 18.5% had amplifications, with the majority identified in CCNE1 (40.9%), PIK3CA (22%) and EGFR (19.3%). From the RWE cohort, those with TP53 mutations had a worse overall survival (OS) vs those without TP53 mutations (p=0.02) and those with TP53 co-mutations had an inferior OS in comparison to TP53-mutated only (p=0.016). Amongst these, patients with a PIK3CA co-mutation (p=0.012) and CCNE1 amplification (p=0.01) had inferior OS compared to those with only TP53 mutations. 57 patients with newly diagnosed EC had at least 2 serial ctDNA samples showing evolution in detected variants compared to baseline samples, with TP53 being the most frequent change. CONCLUSIONS: This study is one of the largest cohorts of ctDNA currently reported in EC. The presence of TP53 mutation and other co-mutations detected by ctDNA have a negative effect on outcomes. This report suggests that ctDNA analysis is feasible and could become a useful biomarker for EC.

Impact of Tumor-intrinsic Molecular Features on Survival and Acquired Tyrosine Kinase Inhibitor Resistance in ALK-positive NSCLC.

While tyrosine kinase inhibitors (TKI) have shown remarkable efficacy in anaplastic lymphoma kinase (ALK) fusion-positive advanced non-small cell lung cancer (NSCLC), clinical outcomes vary and acquired resistance remains a significant challenge. We conducted a retrospective study of patients with ALK-positive NSCLC who had clinico-genomic data independently collected from two academic institutions (n = 309). This was paired with a large-scale genomic cohort of patients with ALK-positive NSCLC who underwent liquid biopsies (n = 1,118). Somatic co-mutations in TP53 and loss-of-function alterations in CDKN2A/B were most commonly identified (24.1% and 22.5%, respectively in the clinical cohort), each of which was independently associated with inferior overall survival (HR: 2.58; 95% confidence interval, CI: 1.62-4.09 and HR: 1.93; 95% CI: 1.17-3.17, respectively). Tumors harboring EML4-ALK variant 3 (v3) were not associated with specific co-alterations but were more likely to develop ALK resistance mutations, particularly G1202R and I1171N (OR: 4.11; P < 0.001 and OR: 2.94; P = 0.026, respectively), and had inferior progression-free survival on first-line TKI (HR: 1.52; 95% CI: 1.03-2.25). Non-v3 tumors were associated with L1196M resistance mutation (OR: 4.63; P < 0.001). EML4-ALK v3 and somatic co-alterations in TP53 and CDKN2A/B are associated with inferior clinical outcomes. v3 status is also associated with specific patterns of clinically important ALK resistance mutations. These tumor-intrinsic features may inform rational selection and optimization of first-line and consolidative therapy. SIGNIFICANCE: In a large-scale, contemporary cohort of patients with advanced ALK-positive NSCLC, we evaluated molecular characteristics and their impact on acquired resistance mutations and clinical outcomes. Our findings that certain ALK variants and co-mutations are associated with differential survival and specific TKI-relevant resistance patterns highlight potential molecular underpinnings of the heterogenous response to ALK TKIs and nominate biomarkers that may inform patient selection for first-line and consolidative therapies.

Oncogene Overlap Analysis of Circulating Cell-free Tumor DNA to Explore the Appropriate Criteria for Defining MET Copy Number-Driven Lung Cancer.

INTRODUCTION: Defining clinically relevant MET amplification levels in non-small cell lung cancer (NSCLC) remains challenging. We hypothesize that oncogene overlap and MET amplicon size decline with increase in MET plasma copy number (pCN), thus enriching for MET-dependent states. PATIENTS AND METHODS: We interrogated cell-free DNA NGS results of 16,782 patients with newly diagnosed advanced NSCLC to identify those with MET amplification as reported using Guardant360. Co-occurring genomic mutations and copy number alterations within each sample were evaluated. An exploratory method of adjusting for tumor fraction was also performed and amplicon size for MET was analyzed when available. RESULTS: MET amplification was detected in 207 (1.2%) of samples. pCN ranged from 2.1 to 52.9. Of these, 43 (20.8%) had an overlapping oncogenic driver, including 23 (11.1%) METex14 skipping or other MET mutations. The degree of (non-MET) oncogene overlap decreased with increases in pCN. Patients with MET pCN ≥ 2.7 had lower rates of overlapping drivers compared to those with MET pCN < 2.7 (6.1% vs. 16.3%, P = .033). None of the 7 patients with pCN > 6.7 had an overlapping driver. After adjusting for tumor fraction, adjusted pCN (ApCN) was also lower for those with overlapping drivers than those without (median ApCN 4.9 vs. 7.3, P =.024). There was an inverse relationship between amplicon size and pCN. CONCLUSIONS: We propose that a high MET pCN and/or ApCN, together with the absence of overlapping oncogenic drivers and small MET amplicon size, will enrich for patients most likely to derive benefit from MET targeted therapy.

Landscape of oncoviral genotype and co-infection via human papilloma and hepatitis B viral tumor in situ profiling.

The role of oncoviral genotype and co-infection driving oncogenesis remains unclear. We have developed a scalable, high throughput tool for sensitive and precise oncoviral genotype deconvolution. Using tumor RNA sequencing data, we applied it to 537 virally infected liver, cervical, and head and neck tumors, providing the first comprehensive integrative landscape of tumor-viral gene expression, viral antigen immunogenicity, patient survival, and mutational profiling organized by tumor oncoviral genotype. We find that HBV and HPV genotype and co-infection serve as significant predictors of patient survival and immune activation. Finally, we demonstrate that HPV genotype is more associated with viral oncogene expression than cancer type, implying that expression may be similar across episomal and stochastic integration-based infections. While oncoviral infections are known risk factors for oncogenesis, viral genotype and co-infection are shown to strongly associate with disease progression, patient survival, mutational signatures, and putative tumor neoantigen immunogenicity, facilitating novel clinical associations with infections.

Tumor fitness, immune exhaustion and clinical outcomes: impact of immune checkpoint inhibitors.

Recently proposed tumor fitness measures, based on profiling neoepitopes for reactive viral epitope similarity, have been proposed to predict response to immune checkpoint inhibitors in melanoma and small-cell lung cancer. Here we applied these checkpoint based fitness measures to the matched checkpoint treatment naive Cancer Genome Atlas (TCGA) samples where cytolytic activity (CYT) imparts a known survival benefit. We observed no significant survival predictive power beyond that of overall patient tumor mutation burden, and furthermore, found no association between checkpoint based fitness and tumor T-cell infiltration, cytolytic activity, and abundance (tumor infiltrating lymphocyte, TIL, burden). In addition, we investigated the key assumption of viral epitope similarity driving immune response in the hepatitis B virally infected liver cancer TCGA cohort, and uncovered suggestive evidence that tumor neoepitopes actually dominate viral epitopes in putative immunogenicity and plausibly drive immune response and recruitment.