In addition to the inhibitory effects on mammary tumor growth, buformin also elicits substantial inhibition of cell populations associated with putative MaSCs (MRU population) and CSCs/TICs (ALDH+/CD61highCD49fmid cells) in erbB-2-overexpressing breast cancer cell lines and primary MECs from preneoplastic mammary glands of MMTV-erbB-2 mice (Fig. 3, 6, and 7). The gene discussed is ERBB2; the disease is breast cancer.