CYP26A1 and pharynx cancer: Our results have revealed an important insight into the impact of BQ chewing on the two single nucleotide polymorphisms (SNPs), rs2068888 or rs4418728, of CYP26A1, and oral and pharyngeal cancer risk (rs2068888, odds ratio (OR) = 5.0; 95% CI = 1.1–22.1).