Tumors arising from transplant of single tumor cells recapitulate the histology and cellular composition characteristic of the parental tumors.

<p>(<b>A</b>), Histopathology of a primary mammary tumor from an MMTV-Neu transgenic mouse (subpanel 1), that of a tumor seeded by transplant of a single cell (subpanel 2) from the same primary tumor, and that of a tumor derived from transplant of a single cell dissociated from tumorspheres of the same transgenic strain (subpanel 3). H&E staining of tumor sections illustrates the solid and nodular cytoarchitecture characteristic of Neu-induced tumors. (<b>B</b>), Immunofluorescence analyses of an MMTV-Neu tumor (subpanel 1), that of a tumor seeded by transplant of a single cell (subpanel 2) from the same primary tumor, and that of a tumor (subpanel 3) seeded by transplant of a single tumorsphere-derived cell stained with antibodies to CK8 and CK14. (<b>C</b>), Immunofluorescence analyses of an MMTV-Neu tumor (subpanel 1), that of a tumor seeded by transplant of a single cell (subpanel 2) from the same primary tumor, and that of a tumor (subpanel 3) seeded by transplant of a single tumorsphere-derived cell stained with antibodies to CK8 and α-SMA. Note that distinct sections of the same tumor were used for the analyses shown in panels a–c. Scale bar (inset) represents 40 µm in all panels.