For breast cancer patients, there are conflicting results regarding the prognosis and the predictive value of the BRCA germline status due to several issues: i) the phenotype of the tumor varies whether it is a BRCA1 (mainly TNBC) or a BRCA2 (mainly ER/PR positive) mutations; ii) adjuvant chemotherapy is not systematic and depends, among other characteristics, on tumor stage, grade, and molecular subtypes. Here, ESR1 is linked to breast cancer.