ERBB2 and neoplasm: The mouse model of mammary carcinogenesis driven by the wild-type huHER2 oncogene (referred to as FVB-huHER2 herein) [19] is characterized by tumor onset after more than 40 weeks of age and by low numbers of neoplastic mammary glands, similar to what happens in mice transgenic for the wild-type rat HER2 homologue [10,11,25].