Mutations in genes encoding proteins necessary for detoxifying oxidative stress products have been predicted to increase susceptibility to lung cancer (LC). Despite this, the association between waterpipe tobacco smoking (WP), genetic polymorphisms, and LC risk remains poorly understood. This is the first study to explore the relationship between WP tobacco smoking and these genetic factors. Previously, we investigated the association of GSTP1 SNPs (rs1695-A/G and rs1138272-C/T) with LC in Iraqi males who smoke WP. Here, we expanded our analysis to include GSTM1 (active/null) and GSTT1 (active/null) genotypes, both individually and in combination with GSTP1 SNPs. Multiplex PCR and RFLP-PCR assays were utilized to determine the genotypes of 123 cases and 129 controls. No significant association was observed between GSTM1-null or GSTT1-null genotypes and LC risk, either separately or in combination with variant genotypes of GSTP1 (rs1695 "AG+GG" and rs1138272 "CT+TT"). However, smoking WP and carrying null genotypes elevated the risk five-fold for GSTM1-null (OR 5.17, 95 % CI 2.02–13.24, P<0.001) and three-fold for GSTT1-null (OR 3.08, 95 % CI 1.55–6.13, P=0.001) compared to non-smokers carrying active genotypes. Conversely, genotype distribution analysis based on LC histological types did not indicate an increased risk of LC. Lung cancer is a complex multifactorial disease. WP smoking and GSTs genetic polymorphisms might be associated with an increased risk of developing LC. However, our data did not confirm an association between GST polymorphisms alone and the risk of LC.
