MBD2 and breast cancer: The intracellular dynamic balance of m6A is regulated by methyltransferase and demethylase, and the disorder of m6A balance have been proved to be closely related to the pathological processes of various tumors (such as glioma, leukemia, breast cancer, hepatocellular carcinoma), obesity, Alzheimer’s disease and HIV infection (Giudice et al., 2010; Vu et al., 2017; Wang et al., 2018).