DCUN1D5 cDNA encoded a protein of 237 amino acids, which contained two domains associated with DNA repair and cell cycle regulation. Although no reported studies have clearly demonstrated DCUN1D5’s role in cancer, one report suggested that DCUN1D5 expression may be useful as a biomarker for cervical cancer. Because DNA damage and repair pathways played critical roles in the development of LSCC, a smokingrelated cancer, and because DCUN1D5 was found to be up-regulated in our patients with LSCC who had a tobacco history, that DCUN1D5 had a vital function involved in DNA damage response and repair in the carcinogenesis of LSCC.