Notably, HSC3 cells overexpressing constitutively active NEDD8 showed a poorer irradiation response than wild-type NEDD8-overexpressing HSC3 cell variants (Fig. 3E and F), implying the involvement of its enzymatic modification, neddylation, toward target proteins in radioresistance in oral cancer. This evidence concerns the gene NEDD8 and lip and oral cavity carcinoma.