Clinical and pathological findings of the two series: age, tumor size, histological type, grading according to Scarff‐Bloom Richardson grading system, lymph node status at the time of diagnosis in axillary lymphadenectomy specimens and the immunohistochemical expression of estrogen and progesterone receptors (ER/PR), HER2 and Ki‐67, were collected from the pathological reports. The gene discussed is ESR1; the disease is neoplasm.