CDNR4 is one of several clonal subpopulations of the original mouse mammary carcinoma COMMA-D, established by transfection with a dominant-selectable gene, pSV2Neo. The subline designated CDNR4 retained hyperplastic growth potential after multiple passages in vitro with low incidence of tumor formation. It is assumed that this cloned subset may be functionally analogous to stem cells existing in the mammary gland. The species was confirmed by Real-Time PCR.