In terms of MAOA and COMT, subjects with MAOA rs6323 (G-allele) and COMT rs4633 (C/C genotype) had a significantly increased risk of oral and pharyngeal cancers (AOR = 2.94; 95% CI, 1.50–5.76) and risk of OPMD (AOR = 4.74; 95% CI, 1.54–214.57). This evidence concerns the gene COMT and oculopharyngeal muscular dystrophy.