GSTM3 and lip and oral cavity carcinoma: In the Caucasian population, the GSTM3 A/B polymorphism had significant protective effects on the risk of HNC in three genetic models (OR = 0.83, 95%CI: 0.72–0.95 for the dominant model; OR = 0.69, 95%CI: 0.49–0.99 for the homozygote comparison model; OR = 0.85, 95%CI: 0.73–0.98 for heterozygote comparison model), but no significant association was observed under the recessive model (OR = 0.73, 95%CI: 0.51–1.03); while only one study focused on African-American, found that the GSTM3A/B polymorphism play an important role in risk for oral cancer (Table 2).