Immunohistochemistry of the biopsy specimen showed that the tumor cells had positive cytoplasmic staining for epithelial membrane antigen (EMA), S-100 (Fig. 4 g), vimentin, and positive cytomembrane staining for E-Cadherin (Fig. 4 h) while it was triple-negative for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor type 2 (HER2). The gene discussed is ESR1; the disease is neoplasm.