In our study, the combinations of two (CYP1A1 m2 and GSTM1) or three (CYP1A1 m1, CYP1A1 m2 and GSTM1/GSTT1) genotypes had a profound effect on susceptibility to lung cancer up to 14-fold depending on the genotypic interaction. Here, GSTM1 is linked to lung cancer.