Heterozygous genotype in CYP1A1*2A was associated with increased risk (OR = 1.69,95% CI = 1.11−2.59; p = 0.01) whereas heterozygous genotypes in EPHX1 Tyr113His and SULT1A1 Arg213His imparted reduced risk towards lung cancer (OR = 0.40;95%C.I = 0.25−0.65,p<0.001 and OR = 0.51;p = 0.33x−0.78,p = 0.002 respectively). The gene discussed is EPHX1; the disease is lung cancer.