Pan-cancer analysis of homologous recombination deficiency and homologous recombination repair–associated gene alterations in solid tumors from a large Asian cohort
Lili Ren, Runsi Yao, Ting Hou, Cheng‐Lin Liu, Fei Zhao, Xiaojun Chen, Zhou Zhang, Yan Huang
Abstract
BACKGROUND: Homologous recombination deficiency (HRD) is associated with sensitivity to platinum-based chemotherapy and PARP inhibitors in BRCA-associated cancers, including ovarian, breast, prostate, and pancreatic cancers. This study explores HRD and homologous recombination repair (HRR) gene alterations in a pan-cancer cohort to guide precision oncology. METHODS: Plus kit. HRD scores, biallelic HRR and tumor suppressor gene alterations, and their clinical correlations were evaluated. RESULTS: HRD scores varied across cancer types, all showing a long tail in distribution. The prevalence of pathogenic alterations in pan-cancer HRR was 21.3%, with 13.7% of the cases having an HRD score ≥42. HRD-related events (LOH, LST, and TAI) exhibited similarities and cancer-specific patterns at the chromosomal arm level. Biallelic loss of HRR genes, especially BRCA1, BRCA2, RAD51D, RAD51 C, and PPP2R2 A was linked to higher HRD scores in BRCA-associated cancers, while BARD1, RAD51D, RAD54L, BRCA1, and MRE11 were associated with elevated HRD scores in in other cancer types (non-BRCA cancers). TP53 biallelic alterations, with or without HRR alterations, were linked to increased HRD scores. Higher HRD scores were associated with late-stage, older, metastatic, PD-L1 positive, non-MSI-H/non-POLE samples were correlated with genomic instability indexes, such as structural chromosomal instability (SCIN), weighted genome instability index (WGII), and whole-genome doubling (WGD). CONCLUSIONS: This is the largest pan-cancer HRD study in an Asian population, providing insights for future HRD testing and targeted therapy.