Data for serum positivity of oncoprotein-specific (T-antigen) antibodies, presence of MCPyV-specific tetramer+ CD8+ T cells, positivity of CD8+ T cell IFN-γ expression in response to MCPyV peptides and clinical response according to RECIST 1.1 is summarized for patients with VP-MCC tumors in Table 1. This evidence concerns the gene IFNG and Merkel cell skin cancer.