POU5F1 and Merkel cell skin cancer: The high Oct4 expression of all hiPSC_A4_L82-derived VP-MCC-like tumors, in contrast to very low or absent expression in VP-MCC lines or hPGCLC_A4_L82 derived VP-MCC-like tumors (Figures S19–S21, Tables S2C,D and S3), raised concerns about a possible embryonic carcinoma component in these VP-MCC-like tumors.