The results indicated that knockdown of PELI1 in TE‐1, SCC‐9 or SiHa tumor cells further promoted the reduction of IR‐induced Lys48‐linked polyubiquitination of NIK (Fig. 5H, Fig. S4G), whereas overexpression of PELI1 in tumor cells significantly inhibited the IR‐induced reduction of Lys48‐linked polyubiquitination of NIK (Fig. 5I, Fig. S4H). Here, MAP3K14 is linked to neoplasm.