Comprehensive Analysis of the Expression and Prognosis for RAD51 Family in Human Breast Cancer

Purpose: The RAD51 family of genes, including RAD51 and the five RAD51-like paralogs (RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3), are known to be crucially associated with DNA damage repair pathway. Increasing evidence indicated that RAD51 family members were implicated in breast cancer tumorigenesis. However, their biological roles and prognostic values in breast cancer have yet to be clarified. Methods: In this study, by using the Oncomine and GEPIA databases, we explored the transcriptional levels of RAD51 family members in breast cancer. Besides, the associations between RAD51 family expression and clinical features were evaluated by using the UALCAN database and Kaplan-Meier (KM) Plotter. We also analyzed the mutations of the RAD51 family and differentially altered genes from the cBioPortal database. Results: We found that RAD51 mRNA was significantly elevated in breast cancer samples than in normal tissues, while XRCC2 mRNA was downregulated. Besides, a remarkable correlation was detected between the expression of RAD51/RAD51B/XRCC2 genes and the breast cancer stage. Survival analysis utilizing the KM Plotter indicated that high RAD51 and XRCC3 mRNA was associated with a poor prognosis. Conversely, RFS data suggested that high levels of RAD51B/RAD51C/RAD51D/XRCC2 were associated with a favorable prognosis. Moreover, a high genetic variation rate of RAD51C (7%) was detected in breast cancer patients. Conclusion: Conclusively, we implied that RAD51 and XRCC3 might be potential targets for precision therapy in breast cancer and the RAD51B/RAD51C/RAD51D/XRCC2 genes have significant values for breast cancer prognosis.