Overall, a significantly elevated risk of lung cancer was associated with 2 variants of CYP1A1 MspI (for Type C vs Type A: OR = 1.26, 95% CI = 1.12-1.42, P = 0.003 for heterogeneity; for types B and C combined vs Type A: OR = 1.20, 95% CI = 1.13-1.28, P = 0.000 for heterogeneity) (Figure 2). The gene discussed is CYP1A1; the disease is lung cancer.