It is hypothesized that haplotypes of DNMT3B polymorphisms may regulate the susceptibility to lung cancer, and among the three DNMT3B polymorphisms (−149C>T, −579G>T, and −283T>C), the haplotype −283T/−579G is reported to have a decreased effect on the risk of lung adenocarcinoma [16]. The gene discussed is DNMT3B; the disease is lung cancer.