In a single-center cross-sectional study, stage I-III breast cancer survivors were enrolled according to three groups: (1) BRCA1/2 mutation carriers treated with doxorubicin; (2) BRCA1/2 mutation non-carriers treated with doxorubicin; and (3) BRCA1/2 mutation carriers treated with non-doxorubicin cancer therapy. This evidence concerns the gene BRCA1 and cancer.