In a case-control study on lung cancer, null genotype of GSTM1 has been found to increase the risk of promoter hypermethylation of DAPK and Rarβ. Moreover, they also identified significant interaction of tobacco smoking and null GSTM1 genotype in modulating promoter hypermethylation of multiple TSGs [12]. The gene discussed is DAPK1; the disease is lung cancer.