The miRNAs (miR)-29 family (29a, 29b, and 29c), which have an intriguing complementarity with the 3’-UTRs of DNMT-3a and -3B, have been shown to be downregulated in lung cancer, which led to elevated expression levels of DNMT-3a and -3B associated with a poor prognosis. This evidence concerns the gene DNMT3A and lung cancer.