BQ chewers with the CYP26A1 rs4411227 C allele and CYP26B1 rs3768647 G allele had the highest risk of oral and pharyngeal cancer compared with the subjects carrying the CYP26A1 rs4411227 G allele and CYP26B1 rs3768647 C allele (aOR = 29.91; 95%  CI = 10.75–83.23). The gene discussed is CYP26B1; the disease is pharynx cancer.