Despite no evidence is available about a role of this transcription factor in the regulation of PVR gene expression in cancer cells, a search for sequence homology revealed the presence of putative NF-kB binding sites (-254-GGGGAGGGCCAG-243; and -162-GTGGGTATTCCC-150) in the region of PVR(B) promoter spanning −343 bp from the transcription start site. This evidence concerns the gene NFKB1 and cancer.