The available information included the age of breast cancer diagnosis, deaths, year of breast cancer surgery, the treatment oncology center, lymph node status, tumor size, histopathology, estrogen-receptor status, progesterone-receptor status, HER2 status, multicentricity, bilaterality, previous treatment (chemotherapy, radiotherapy, hormonotherapy), adnexectomy, other concomitant cancers in probands and family history. This evidence concerns the gene ESR1 and breast cancer.