DNMT3B and breast cancer: Another group showed that microRNA-29b (miR-29b) can bind with 3′-UTR of DNMT3A and DNMT3B and inhibit the mRNA level of DNMT3A and DNMT3B, leading to multiple gene promoter methylation in breast cancer cells and suppression of cell proliferation (Starlard-Davenport et al., 2013).