Although numerous studies have established NF-κB as a tumor-promoting transcription factor,30 recent studies have shown that NF-κB can also act as a tumor suppressor.31, 32, 33, 34 Because NF-κB activity enhances sensitivity to cytotoxic chemotherapy in certain cancer cell lines, the two opposing roles of NF-κB may be explained by the other oncogenic status.35 For example, as β-catenin is overexpressed in colorectal cancers and functions as an oncogene, NF-κB could act as a tumor suppressor in colorectal cancer cells. This evidence concerns the gene NFKB1 and neoplasm.