ERBB2 and neoplasm: In the context of our previous study (Zhu et al., 2014), results from both MMTV-erbB2 transgenic mice and the parental non-tumor FVB/N strain suggested that the basal subpopulation is the primary cellular target of metformin in premalignant tissues, indicating that metformin-induced MEC reprogramming is not limited to tissues with oncogene overexpression.