Importantly, in TRAF4 knockout-xenograft tumors, the reintroduction of the TRAF4 C18A mutant did not compromise the antitumor effect of irradiation (Fig. 6A), indicating that the E3 ligase activity of TRAF4 was required for radioresistance in CRC cells. This evidence concerns the gene TRAF4 and colorectal carcinoma.