Abstract: Objective To investigate the expression of breast cancer susceptibility gene 1 (BRCA1) and BRCA2 in epithelial ovarian cancer (EOC), and analyze their relationship with prognosis.Methods A total of 98 EOC patients who were admitted to Nantong Cancer Hospital from January 2019 to June 2023 were selected. Their fresh cancer tissues and adjacent normal tissues intraoperatively resected were collected. The expression of BRCA1 and BRCA2 mRNA in the tissues were detected by real-time quantitative polymerase chain reaction (qRT-PCR). The relationship between the relative expression of BRCA1 and BRCA2 mRNA and clinicopathological features was analyzed, and their effect on overall survival (OS) and progression-free survival (PFS) of EOC patients were analyzed by Kaplan-Meier survival curves and Cox regression risk models.Results The BRCA1 and BRCA2 mRNA levels and relative protein expression in EOC tissues were lower than those in adjacent normal tissues (P<0.05). The levels of BRCA1 and BRCA2 mRNA in patients with ascites ≥500 mL, International Federation of Gynecology and Obstetrics (FIGO) stage Ⅲ—Ⅳ, and lymph node metastasis were lower than those in patients without ascites or with ascites <500 mL, with FIGO stage Ⅰ—Ⅱ, and without lymph node metastasis (P<0.05). The patients were followed up from 9 to 50 months, with a median follow-up time of 27 months, and a follow-up rate of 95.92% (4 patients were lost visited). During follow-up visits, 39 patients (39.80%) relapsed and 26 (26.53%) died. Kaplan-Meier survival analysis showed that the cumulative survival rate of patients with high expression of BRCA1 and BRCA2 mRNA was higher than that of those with low expression (P<0.05). Cumulative progression-free survival was higher in patients with high expression of BRCA1 and BRCA2 mRNA than in those with low expression (P<0.05). Multifactorial Cox regression analysis indicated that chemotherapy ≤6 courses, ascites ≥500 mL, FIGO stage Ⅲ+Ⅳ, and low expression of BRCA1 and BRCA2 mRNA were independent risk factors affecting OS in EOC patients (P<0.05). Postoperative residual foci >2 cm, chemotherapy≤6 courses, ascites ≥500 mL and low expression of BRCA1 and BRCA2 mRNA were independent risk factors affecting PFS in EOC patients (P<0.05).Conclusions Abnormally low expression of BRCA1 and BRCA2 in EOC tissues and low expression of BRCA1 and BRCA2 mRNA are closely related to the clinicopathologic features of patients and affected their PFS and OS.