In terms of MAOA, MAOB, and COMT, subjects with the MAOA rs6323 G-allele, MAOB rs6324 G-allele, and COMT rs4633 C/C-genotype had a significantly increased risk of oral and pharyngeal cancers (AOR = 56.99; 95% CI, 15.82–205.31). Here, COMT is linked to pharynx cancer.