MBD2 and breast cancer: Moreover, Mbd2 protein expression was markedly increased in mammary fat pads (mfp) and primary tumors obtained from transgenic PyMT mice compared to the fat pads of WT C57BL/6 mice, indicating that Mbd2 upregulation mediated by the PyMT gene precedes the appearance of measurable mammary tumors (Fig. 1d).