The evidences that enhanced expression of MiR-29s in lung cancer cell lines A549 and H1299 restored normal silenced TSG, such as FHIT and WWOX, and inhibit tumorigenicity both in vitro and in vivo, resulted in a conclusion that expression of the MiR-29s (29a, 29b, 29c) was inversely correlated to DNMT3A and -B expression in lung cancer tissues and that MiR-29s directly target the 3’-UTRs of Dnmt3a and -3b [167]. The gene discussed is WWOX; the disease is lung cancer.