Lung metastatic properties of cell lines with or without CD44+/CD24- subpopulation. (a) Hematoxylin and eosin staining of lungs in animals injected with TMD-231, TMD-436, MDA-MB-468, and DU4475 cells. Metastasis was not observed with DU4475. (b) Faxitron images of calcified tumor growth in animals injected with TMD-231 but not with TMD-436 cells (left and center). Dual energy X-ray absorptiometry whole-body scan of an animal injected with TMD-231 cells is shown on right.