In addition, increased risk for HNC was associated consistently with the ALDH2*1/*2, p53 codon 72 Pro/Pro and EPHX1 codon 113 Tyr/His and His/His genotypes.
Combinations of the Y113H and H139R polymorphic EPHX1 variants have been assumed to alter the enzyme activity and thus the risk of squamous cell head and neck cancer (SCCHN).