Genetic landscape of homologous recombination repair and practical outcomes of PARPi therapy in ovarian cancer management

Abstract

Background: Genetic studies of ovarian cancer (OC) have historically focused on BRCA1/2 mutations, lacking other studies of homologous recombination repair (HRR). Poly (ADP-ribose) polymerase inhibitors (PARPi) exploit synthetic lethality to significantly improve OC treatment outcomes, especially in BRCA1/2 deficiency patients. Objectives: Our study aims to construct a mutation map of HRR genes in OC and identify factors influencing the efficacy of PARPi. Design: A retrospective observational analysis of HRR gene variation data from 695 OC patients from March 2019 to February 2022 was performed. Methods: The HRR gene variation data of 695 OC patients who underwent next-generation sequencing (NGS) in the First Affiliated Hospital of Zhengzhou University were retrospectively collected. Clinical data on the use of PARPi in these patients were also gathered to identify factors that may interfere with the efficacy of PARPi. Results: Out of 127 pathogenic variants in the BRCA1/2 genes, 104 (81.9%) were BRCA1 mutations, and 23 (18.1%) were BRCA2 mutations. Among the 59 variants of uncertain significance (VUS), 20 (33.9%) were BRCA1, while 39 (66.1%) were BRCA2 mutations. In addition to BRCA1/2, HRR gene results showed that 9 (69%) of 13 were HRR pathway pathogenic variants; and 16 (1.7%) of 116 VUS were Food and Drug Administration (FDA)-approved mutated HRR genes. Notably, the treatment regimen significantly influenced the effectiveness of PARPi, especially when using first-line maintenance therapy, leading to enhanced progression-free survival (PFS) compared to alternative protocols. Conclusion: Focusing on HRR gene mutations and supporting clinical research about PARPi in OC patients is crucial for developing precision treatment strategies and enhancing prognosis.