MBD2 and neoplasm: The initiation of palpable tumors was delayed in the PyMT-Mbd2−/− group compared to that in the wild-type PyMT-Mbd2+/+ group (log–rank P = 0.002), in which tumors started to develop beginning in week 12, and all the KO mice had developed palpable tumors by week 16 of age [time to PyMT-Mbd2−/− tumor incidence: 12–16 weeks], suggesting the possible involvement of Mbd2 in tumorigenesis in this model.