To investigate the association between CYP1A1 polymorphism (MspI) and risk for OSCC in the Korean [63] and the Indian [64] populations, many studies have been conducted, and they found that the risk for oral cancer was significantly increased in subjects of these populations with the homozygous CYP1A1 (m2/m2) genotype (Indian: OR = 3.2, 95% CI = 1.10–10.28, and P = 0.05; Korean: OR = 3.8, 95% CI = 1.9–7.7, and P = 0.023), regardless of smoking history (smokers: OR = 4.4, and 95% CI = 1.2–16.3; nonsmokers: OR = 4.9, and 95% CI = 1.9–12.5). The gene discussed is CYP1A1; the disease is lip and oral cavity carcinoma.