NFKB1 and neoplasm: Finally, Tax failed to inhibit TAX1BP1 phosphorylation, which is critical for the assembly of the NF-κB negative regulator, ubiquitin-editing enzyme A20 complex, in Cadm1-deficient MEFs stimulated with TNF or IL-1, indicating that CADM1 is not only required for Tax to activate NF-κB but also to target NF-κB negative regulators in HTLV-1 mediated tumor cells.