MAOA and lip and oral cavity carcinoma: Table 1 shows that compared with OPMDs patients, BQ chewers who had the MAO-A A-allele (SNP rs2283725) had an increased risk of oral cancer (OR = 1.69; 95% CI = 0.98–2.90), although at borderline significant level. BQ chewers who had the MAO-A G-allele (SNP rs5953210) had a significantly increased risk (OR = 1.76; 95% CI = 1.02–3.01) of oral cancer (P < 0.05).