ERBB2 and breast cancer: To elucidate the roles of Dmp1α in mammary tumor development and prevention of HER2;neu-induced mammary carcinogenesis, we created transgenic mice that constitutively express the Flag-tagged murine Dmp1α gene under the control of the MMTV promoter (MMTV-Flag-Dmp1α, MDTG) (Fig. S1; strain 138 results, not shown).