A pathological examination revealed the following: invasive ductal carcinoma, pT2 (22 mm), nuclear grade 3, pN0, estrogen receptor (ER) and progesterone receptor (PgR) positive, human epidermal growth factor receptor 2 (HER2) negative, and pT2N0M0 stage IIa. This evidence concerns the gene ESR1 and invasive ductal breast carcinoma.