CYP26A1 and pharynx cancer: Polymorphisms in both CYP26A1 (rs4411227 C/G genotype or C/C+C/G compared to G/G) and CYP26B1 (rs9309462 C/T genotype and C allele, rs138478634 G/A change in exon 5) alone or combined polymorphisms (CYP26A1 rs4411227 and CYP26B1 rs3768647/rs930946) have an increased risk of oral and pharyngeal cancer [209,210,211,212].