In terms of immunohistochemistry, MCC cells are positive for epithelial markers such as CK-CAM5.2, CKAE1-AE3, CK20, CK34BetaE12, BerEP4, and Epithelial membrane Antigen (EMA), PIEZO2 [9], with some cases showing positivity for CK7 along with markers of neuroendocrine differentiation including chromogranin A (CgA), synaptophysin (Syn), and CD56 (NCAM1). Here, MUC1 is linked to Merkel cell skin cancer.