The tumor was an IDC classified as pT1N1M0 with hormone receptor positivity (estrogen receptor ++, progesterone receptor (PR) +++, HER2 +) and was treated with surgery (modified radical mastectomy of the right breast), adjuvant chemotherapy (adriamycin and cyclophosphamide), radiation therapy (46 Gy) and endocrine therapy (tamoxifen). This evidence concerns the gene ESR1 and neoplasm.