CYP1A1 and non-small cell lung carcinoma: There was no significant difference between controls and lung cancer patients regarding the frequency of identified CYP1A1 variants, except for the combined variants CYP1A1*2C/ CYP1A1*4 which associated with 2-times higher risk of lung cancer (OR = 2.03, 95% C.I:1.81–2.29, P = 0.04), specially the non-small cell type (NSCLC) (OR = 2.20, 95% C.I: 1.93–2.50, P value = 0.02) (Table 2) with no significant difference between the pathological subtypes of NSCLC (P > 0.05).