TRAF4 and neoplasm: In the TRAF4-knockout HT29 tumors, reintroduction of WT TRAF4 impaired the anti-tumor effectiveness of the chemotherapeutic agents, but reintroduction of the DM-RING and C18A TRAF4 mutants, which both lack the E3 ligase activity, did not (Fig. 5n–p, Fig. S5n).