Abstract 2446: Genomic landscape of longitudinally collected preinvasive airway lesions

Abstract Lung carcinoma in situ (CIS) lesions, as precursors to squamous cell carcinoma, exhibit microscopic uniformity while displaying diverse clinical trajectories. Half of these lesions progress to invasive cancer, while the remaining half either regress or remain indolent. Previous genomic profiling efforts have elucidated progression-specific genomic changes against a backdrop of inherent heterogeneity and notable chromosomal instability signatures. Here, we present a novel approach by analyzing longitudinally collected samples of preinvasive airway lesions, encompassing both progressive and indolent trajectories. Our findings reveal that genomic integrity and cell cycle dynamics constitute key distinctions between progressive and indolent lesions. Notably, a decrease in clonal diversity and an inverse correlation between TCRA-Tcell fraction and genomic instability are observed as lesions approach invasion. Somatic mutations in cancer driver genes BRAC2, CSMD3, and MUC16 are found significantly associated with lesion progression. Furthermore, progressive lesions exhibit a higher frequency of copy number changes compared to indolent lesions. Copy number loss in 1p, 3p, 9p, and 17p are found to be significantly associated with lesion progression. Phylogenetic analysis further confirms positive selection for copy number loss in these specific genomic regions, providing insights into the evolutionary trajectory of alterations in progressive lesions. The comprehensive understanding derived from these genomic analyses is anticipated to advance early detection strategies, mitigate overtreatment, and facilitate the development of preventative therapies targeting early clonal events in lung cancer. Citation Format: Ahmed Alhendi, Lukas Kalinke, Adam Pennycuick, Kate Davies, Pascal Durrenberger, Kate Gowers, Kristiana Grigoriadis, Nicholas McGranahan, Sam Janes. Genomic landscape of longitudinally collected preinvasive airway lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2446.