MCPyV interference with the NF-κB pathway is further sustained by the observations that IκB levels were 60% lower in the MCPyV-positive MCC cell line MKL-1 compared with MCPyV-negative MCC13 cells, and by a declined expression of NF-κB and NF-κB-associated genes in virus-positive MCC compared to virus-negative MCC [99,117]. Here, NFKB1 is linked to Merkel cell skin cancer.