TCF3 and Merkel cell skin cancer: Using our IMR90 cell line model expressing MCPyV-ER, we discovered that canonical Wnt signaling genes, including WNT3, TCF7, and TCF3, are associated with neuroendocrine marker expression, whereas noncanonical Wnt genes, like WNT5A, WNT5B, and WNT16 are negatively correlated with MCC markers, consistent with previous findings of low WNT5A expression in MCC cells (35).