Patients with oral and pharyngeal cancers and specific SNP (CYP26B1 rs887844 (A/G), CYP26A1 rs4411227 (C/G), CYP26C1 rs12256889 (A/C), and CYP26B1 rs707718 (G/T)) and environmental factor (> 50 old) combinations exhibited significantly increased risks (6.76-, 4.16-, 3.94-, and 2.80-fold, respectively) compared to health controls with high prevalence of BQ chewing. The gene discussed is CYP26A1; the disease is pharynx cancer.