Similarly to the GSTM1 present/null polymorphism, the meta-analysis carried out by Ye et al.[19], including 9,636 cases and 12,322 controls from 44 studies, revealed an increased lung cancer risk associated with the variant genotype of GSTT1. However, when only studies with more than 500 case/control pairs were considered, no association was observed. This evidence concerns the gene GSTM1 and lung carcinoma.