DNMT1 and lung cancer: One particular miRNA family, the miR-29 family (comprising mIR-29a, -29b, and -29c) has been shown to directly target DNMT3A and -3B and indirectly DNMT1 [25-27], In this regard, the mIR-29 family was found to be downregulated in NSCLC and enforced expression of miR-29s in lung cancer cell lines restored normal patterns of DNA methylation, induced reexpression of methylation-silenced tumor suppressor genes, and inhibited tumorigenicity in vitro and in vivo [25] (Table 1).