Immunohistochemical profile of MC includes positivity for CK7, CAM5.2, EMA, CEA, GCDFP-15 (gross cystic disease fluid protein 15), RCC (renal cell carcinoma) antigen, WT1 (Wilms’ tumor protein), ER, PR, and AR [93,98,99]. The gene discussed is ESR1; the disease is renal cell carcinoma.