Introduction/Background RAD51 complex consists of five proteins (RAD51B, RAD51C, RAD51D, XRCC2 y XRCC3), which play an essential role in DNA repairing through homologous recombination of DNA strands.

RAD51C is associated with an absolute risk of breast cancer of 17%-30% and a 10%-15% absolute risk for epithelial ovarian cancer, and RAD51D with 17%-30% and a 10%-20% respectively.

The aim of the present study is to evaluate the percentage of women carrying this mutation in our institution and to evaluate their epidemiological characteristics.

Methodology Retrospective observational study.

Review of patients followed in the inherited cancer unit in a single tertiary hospital between 1st January 2012 until 15th October 2023.

The statistical analysis was carried out using SPSS 22.0.

Results During the indicated period, we followed 552 patients with confirmed genetic mutations that predispose to developing gynaecological cancer.

1.63% (9/552) of patients carried RAD51 mutations: 6 of them had mutations in RAD51C (66,7%), and 3 in RAD51D (33,3%). 2.2% (2/9) of patients carrying RAD51 mutations had first degree family history of ovarian cancer whereas 55,6% (5/9) had first or second degree family history of breast cancer. Epidemiological characteristics of these patients are summarized in Table 1.

Discussion The expression of RAD51 has been found in some tumors, especially breast and ovarian cancer. The mutation rate in patients affected by breast and ovarian cancer is estimated to be around 2.5% in some studies, which matches the results of the current study. Despite there are no cases of ovarian cancer within the patients carrying RAD51 mutations, the 44.4% of them debuted with breast cancer (including a bilateral case).

Conclusion According to our results, patients carrying RAD51 mutations seem to present an increased risk of developing breast and ovarian cancer, and should be followed in specialized hereditary cancer units in tertiary hospitals.

Disclosures None.