Abstract

High-grade serous ovarian cancer is the most common subtype of epithelial ovarian cancer and almost half of patients have mutations in homologous recombination repair genes. The RAD51C gene is vital for homologous DNA repair and individuals with pathogenic RAD51C variants exhibit an increased risk of ovarian cancer. PARP inhibitors have been approved as maintenance therapy for ovarian cancer patients. PARP inhibitors can cause synthetic lethality in homologous recombination repair-deficient tumor cells. The present report described two high-grade serous ovarian cancer cases with rare germline RAD51C gene mutations, who received niraparib maintenance therapy. Both patients had undergone primary debulking surgery, followed by complete standard courses of paclitaxel and carboplatin chemotherapy. PARP inhibitor niraparib was initiated after chemotherapy, and both cases sustained relapse -free up to the manuscript submission. In conclusion, this report indicates that the investigation of homologous recombination repair gene variants might be beneficial for treating patients with ovarian cancer.

Keywords: RAD51C Gene Mutation; Ovarian Cancer; PARP Inhibitor; Case Report.

Abbreviations: HRR: Homologous Recombination Repair; HGSOC: High-Grade Serous Ovarian Cancer; OC: Ovarian Cancer; Parpi: Poly-Adenosine Diphosphate Ribose Polymerase Inhibitors; NGS: Next-Generation Sequencing; ECOG: Eastern Cooperative Oncology Group; CT: Computed Tomograph; CA125: Cancer Antigen 125; HE4: Human Epididymis Protein 4; HRD: Homologous Recombination Deficiency; PFS: Progression-Free Survival