The molecular mechanism by which MCPyV may perturb gene expression in virus-positive MCC tumor cells is not known, but several of the genes listed in Table 2 (e.g., CXCL9, IL-2, IL-8, MHC-I, IκB) are known to be a target for NF-κB [115,116]. This evidence concerns the gene NFKB1 and Merkel cell skin cancer.