NFKB1 and cancer: Mutations and enrichment of specific single-nucleotide polymorphisms and haplotypes of NFKBIA in human cancer suggest a role as tumor suppressor.5, 6, 7, 8 Other genes negatively regulate NF-κB activation, such as the TNF α-induced protein 3 (TNFAIP3; A20), a ubiquitin-editing enzyme which downregulates NF-κB signaling when binding TNFAIP3-interacting proteins 1 and 2 (TNIP1 and TNIP2, respectively).9