Immunohistochemical analysis showed that the tumor cells were positive for cytokeratin (CK) (+), epithelial membrane antigen (EMA) (+), cell proliferation nuclear antigen Ki-67 (+5–10%), gross cystic disease fluid protein 15 (GCDFP-15) (+) (Fig. 2), estrogen receptor (ER) (+) (Fig. 3) and progesterone receptor (PR) (+) ; other indicators, such as vimentin (Vim), synaptophysin (Syn), chromogranin A (CgA), Acid calcium binding protein S-100, smooth muscle actin (SMA), leucocyte common antigen (LCA) and carcinoembryonic antigen (CEA), were negative. The gene discussed is ESR1; the disease is neoplasm.