GSTM1 and lung cancer: The most recent and large meta-analysis [9] of Chinese population found that lung cancer risk for CYP1A1 variant was 1.34-fold (95%CI 1.08-1.67, p = 0.008) compared with the wild-type homozygous genotype, and the risk for the GSTM1 null genotype was 1.54-fold (95%CI 1.31-1.80, p < 0.001) as compared with the GSTM1 present genotype.