The lesion in the left lower outer region of the left breast was a non-invasive ductal carcinoma of the breast [pTis, pN0, cM0, pStage 0, ER-positive (70%), PR-positive (25%), HER2-positive (score3),and Ki-67 labeling index 18%] (Fig. 5b). The gene discussed is ESR1; the disease is invasive ductal breast carcinoma.