Of the mammary tumor-derived cell lines, 3 were from benign tumors as determined by histopathological analysis: CMTM1, characterized as an intraductal papillary adenoma; CMTM11, identified as a tubular adenoma with cellular dysplasia; and CMTP3, a benign mixed tumor with intraductal papillary adenoma features. This evidence concerns the gene CMTM1 and benign neoplasm.