ESR1 and melanoma: Other specific IHC markers can be used to distinguish metastases from less common primary sites, including renal cell carcinoma (CK7−, CD10+, RCC+) [73], cervical carcinoma (p16+, ER−, PR, and positive HPV status) [74–76], and malignant melanoma (S-100, MART-1, HMB-45, and SOX10) [77].