Abstract LB147: Fine-scale mapping of chromosome 9q22.33 identifies candidate causal variant in ovarian cancer

Abstract Ovarian cancer is a complex polygenic disease in which genetic factors play a significant role in disease etiology. Genome-wide association study(GWAS) identified a novel variant on chromosome 9q22.33as a susceptibility locus of epithelial ovarian cancer (EOC) in Han Chinese population. However, the underline mechanism of this region was still unknown. In this study, we conducted a fine-mapping analysis of 130kb region including 1,039 variants in 200 health women. Ten variants were selected to evaluate the association with EOC risk in 1,099 EOC cases and 1,591 controls. We identified two variants were significantly associated with ovarian cancer risk (rs7027650, P=1.91 × 10−7; rs1889268, P=3.71 × 10−2). Expression quantitative trait locus (eQTL) analysis found thatrs7027650was significantly correlated with COL15A1 gene expression (P=0.009). Luciferase reporter gene assay confirmed that rs7027650 could interact with the promoter region of COL15A1 to reduce its activity. Electrophoretic Mobility ShiftAssay (EMSA) showed theallele-specific binding capacity of rs7027650. These findings revealed that rs7027650 may be a potential causal variant at 9q22.33 region and may regulate the expression level of COL15A1. This study provided a clue for the molecular mechanism of potential causal variantaffecting the risk of ovarian cancer. Citation Format: an Li, Tongyu Xing, Yanrui Zhao, Kexin Chen, Hong Zheng. Fine-scale mapping of chromosome 9q22.33 identifies candidate causal variant in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB147.