Abstract 5015: Genomic profiling of colorectal cancer - insights from liquid biopsy comparisons between U.S. and China cohorts

Abstract Background: Molecular characteristics play a pivotal role in cancer diagnosis, treatment selection, and disease monitoring across various tumor types. While previous research has elucidated the molecular classification of colorectal cancer using tissue NGS, limited investigation has explored the molecular profile of colorectal cancer through liquid biopsy, especially across diverse human races. This study presents a comprehensive genomic profiling analysis of colorectal cancer patients, using a globally harmonized liquid biopsy assay to compare patient cohorts from both the U.S. and China. Methods: The prospective study is part of Predicine’s Phoenix Program, a global molecular biomarker screening initiative across multiple solid tumors. At present, the study has enrolled 57 patients in the U.S. and 62 patients in China, all presenting with advanced colorectal cancer. A 10ml blood sample was collected from each patient and tested using PredicineCARE, an NGS-based liquid biopsy assay, to profile somatic mutations, copy number variations, and gene fusions among these patients. Results: The assay, validated in both the U.S. and China using the same reference materials, achieved a LOD of 0.25% mutation allele frequency, with a positive predictive value exceeding 99%. Subsequently, the assay was applied to profile molecular aberrations in colorectal patients in both the U.S. and China. Among U.S. patients, the most commonly altered genes were APC (60%), KRAS (56%), TP53 (54%), MYC (25%), PIK3CA (16%), and EGFR (14%). In Chinese patients, the predominant altered genes were TP53 (48%), APC (42%), KRAS (32%), GNAS (21%), EGFR (16%), and PIK3CA (11%). The prevalence of GNAS variations was significantly higher in China than in the U.S. (p < 0.05), while the prevalence of APC (p < 0.05), KRAS (p < 0.01), and MYC (p < 0.001) variations was significantly higher in the U.S. than in China. Conclusions: This study reveals the extensive mutational landscape in advanced colorectal cancer patients through liquid biopsy. Distinct prevalence patterns in certain genes between the U.S. and China cohorts offer novel biomarkers for clinical diagnosis and provide insights for targeted therapy mechanism studies. Citation Format: Haoran Tang, Cancan Jia, Feng Xie, Yue Zhang, Xiaoxi Dong, Yong Huang, Shidong Jia. Genomic profiling of colorectal cancer - insights from liquid biopsy comparisons between U.S. and China cohorts [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 5015.