When miR-29b was replaced by DNMT3B, smokers with higher DNMT3B mRNA expression (OR 2.96, 95% CI 1.94–4.50) and smokers with lower DNMT3B mRNA expression (OR 1.17, 95% CI 0.72–1.89) also had an increased risk of lung cancer compared to non-smokers with lower DNMT3B mRNA expression. This evidence concerns the gene DNMT3B and lung cancer.