Interactions between smoking and each of 11 variables—age, gender, alcohol drinking status, the primary sites of tumors, tumor grades, stages, the number of lymph node metastasis, UGT2B17-deletion, CDKN2A-SCNAs, p16 (+), and a combination of UGT2B17-deletion and p16 (+)—were assessed (Table 2). The gene discussed is CDKN2A; the disease is neoplasm.