GSTM1 and non-small cell lung carcinoma: Strikingly, the risk strongly increased in smokers with null GSTM1, and the OR was 17.84 for NSCLC with p16 promoter hypermethylation, 17.41 for DAPK, and 8.18 for RARβ in smokers with null GSTM1 compared with controls.