Improved detection of homologous recombination deficiency using WES sequencing: Insights into a Chinese pan-cancer cohort.

e17503 Background: Homologous recombination (HR) deficiency has emerged as a novel biomarker for the clinical use of PARP inhibitors in advanced ovarian cancer, and may also be of value in guiding the clinical use of PARP inhibitors and platinum-based drugs in breast cancer, prostate cancer, and other tumors. This significant finding assists in precision medication and prognosis judgments for patients. Methods: This research incorporated a Chinese pan-cancer cohort comprising 1033 patients diagnosed across thirteen cancer types. All matched tumor tissues and peripheral blood samples were processed for the whole exome sequencing. The HRD scoring was conducted with ScarHRD R package with defined parameters for the heterozygosity (LOH), telomeric allelic imbalance (TAI), and large-scale state transitions (LST) status. HR deficiency were defined as an HRD-score ≥50 or BRCA1/2 deficient, while HR proficiency were defined as an HRD-score <50 and BRCA1/2 intact. Results: Ovarian cancer demonstrates the highest HRD prevalence at 51.85%, surpassing the BRCA1/2 mutation rate of 20.37%. Breast cancer follows with an HRD rate of 45.45%, yet no BRCA1/2 mutations are detected. Other cancers like pancreatic, gastric, and sarcomas also present notable HRD rates (29.41%, 36.84%, and 29.79%, respectively) without corresponding BRCA1/2 mutations. In contrast, cancers such as urological, lung, intestinal, and neurological tumors exhibit a mismatch between HRD rates and BRCA1/2 mutation presence, few patients with notable BRCA1/2 mutations did not have consisted HR-deficient rate, and vice versa. Conclusions: Analysis HRD-score can help to screen a larger population of PARP inhibitor beneficiaries and provide hope to more patients. In the future we will do more dimensional data analysis statistics on this cohort. Table: see text