Abstract 3379: Comprehensive circulating tumor DNA and CTC profiling of treatment naïve early-stage head and neck cancer patients reveals early signature of disease progression

Comprehensive CtDNA and CTC profiling of treatment naïve early-stage head and neck cancer patients reveals early signatures of disease progressionBackground: We performed comprehensive ctDNA analysis on early-stage HNC patients in a pilot study to determine the mutational landscape in HNC patients with a known tobacco history. Methods: We analysed ctDNA of 18 early-stage HNC patients for genomic landscapes using the illumina NextSeq 2000 NGS. A custom-designed OncoIndex gene panel was used for the hybrid capture target-enrichment of critical cancer genes. Panel was designed to detect cancer targeting exonic sequence of 600 genes reporting SNVs and indels along fusions and copy number amplification. The gene panel detected genome-wide signatures including bTMB, MSI (microsatellite instability), HRD (homologous recombination deficiency) prediction and calculate cfDNA tumor fraction. Results: 80 % patients showed presence of at least one CTC in peripheral blood, possibly indicating the progressive disease at the time of presentation. Comprehensive genomic profile obtained from plasma cfDNA of early-stage HNC cancer patients predominantly had low bTMB and MSI Scores (99 % patients). However, HRD and LOH matrix was high for 60 % patients indicating highly dysregulated DNA repair activities. Concurring to these observations, 98 % patients had mutations in key tumor suppressor and DNA damage response (DDR) genes possibly resulting in their loss of function. Besides DNA damage pathway, 60% patients harboured alterations in RTK genes including FGFR, EGFR and PDEGFR family and 32% patients showed activating mutations in Erk1 and its upstream regulators. MSH2 was the most prominently mutated gene (37%) followed by FGFR (32%). Surprisingly, unlike HPV positive advanced HNC cases, TP53 mutations were not detected in any patient, though alterations in TS genes were most prevalent in the study population. 51% alterations resulted into truncated proteins possibly impairing their functions, while 42% alterations were point mutations, 6 % were frameshift and 1 % indels. Presence of mutations in BRAF, PDGFR, FGFR and KIT genes suggested for the potential therapy resistance. Tumor fraction representing ctDNA showed elevated range from 20 % to 45 % with a corresponding ploidy between 2 to 4. Conclusions: Comprehensive ctDNA profile showed major gene alterations in TS and DDR response pathway genes besides mutations in proliferative signaling members. TP53 mutation was not detected, although critical tumor suppressor and DDR genes were predominantly mutated, suggesting for a unique mutation pattern associated with early-stage HNC due to tobacco etiology. Our results suggest that comprehensive ctDNA analysis along CTC profiling can predict the disease progression beforehand and may offer new treatment options to early-stage HNC patients.

Citation Format: Gowhar Shafi, Atul Bharde, Fauzul Moubeen, Kanchan Hariramani, Alain D’Souza, Trupti Kad, Bhagwat Jadhav, Sangita Prajapati, Aditi Rani, Madhura Basavalingegowda, Mohan Uttarwar, Gourishankar Aland, Sreeja Jayant, Aravindan Vasudevan, Pankaj Chaturvedi, Jayant Khandare. Comprehensive circulating tumor DNA and CTC profiling of treatment naïve early-stage head and neck cancer patients reveals early signature of disease progression [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 3379.

The future of lung cancer therapy: Striding beyond conventional EGFR and ALK treatments

Lung cancer, one of the most frequently diagnosed cancers worldwide has long relied on testing for the molecular biomarkers EGFR/ALK. However, achieving superior clinical outcomes for patients with lung cancer requires developing comprehensive techniques beyond contemporary EGFR/ALK testing. Current technologies are on par with molecular testing for EGFR/ALK in terms of efficacy, most of them failing to offer improvements perhaps primarily due to skepticism among clinicians, despite being recommended in the NCCN guidelines. The present study endeavored to minimize chemotherapy-dependence in EGFR/ALK-negative patient cohorts, and use evidence-based methods to identify ways to improve clinical outcomes. In total, 137 lung cancer cases obtained from 'PositiveSelect NGS data', comprising 91 males and 46 females, were investigated. EGFR- and ALK-positivity was used for data dichotomization to understand the therapeutic utility of rare gene alterations beyond just EGFR/ALK. Statistics obtained from PositiveSelect were collated with data from international studies to construct a meta-analysis intended to achieve better clinical outcomes. Upon dichotomization, 23% of cases harbored EGFR variants indicating that treating with EGFR TKIs would be beneficial; the remaining 77% exhibited no EGFR variants that would indicate favorable results using specific currently available chemotherapy practices. Similarly, 28% of cases had EGFR+ALK variants favoring EGFR/ALK-based targeted therapeutics; the remaining 72% harbored no EGFR/ALK variants with known beneficial chemotherapy routes. The present study aimed to overcome current inadequacies of targeted therapies in patients with a conventional EGFR/ALK-positive diagnosis and those in EGFR+ALK-negative cohorts. Upon analysis of the negative cohorts, significant and clinically relevant single nucleotide variants were identified in KRAS, ERBB2, MET and RET, with frequencies of 7, 1, 2 and 3% in patients who were EGFR-negative and 6, 1, 1, and 3% in patients who were EGFR and ALK-negative, respectively, enabling the use of targeted therapeutics aside from EGFR/ALK TKIs. From the results of the current study only 35% of the two negative arms (EGFR negative and EGFR+ALK negative) would be recommended NCCN or off-label chemotherapy; prior to the current study, the entire cohorts would have been recommended this treatment. The present study emphasizes the potential of comprehensive genomics in identifying hallmarks of lung cancer beyond EGFR/ALK, using broad-spectrum genetic testing and data-sharing among medical professionals to circumvent ineffective chemotherapy.