Mammary tumors from K14-Cre;Brca1fl/fl;Wwoxfl/fl and K14-Cre;Brca1fl/fl;Wwoxfl/fl;Trp53+/fl mice exhibited elevated number of 53BP1, RAD51 and γH2AX foci per nuclei compared to their normal mammary (Fig. 2A, B and Supplementary Fig. 1). Here, RAD51 is linked to breast cancer.