[Morphological Features of Cancer Stem-Like Cells Derived from a Mouse Tumor]

In 21 of 47 mice, tumor development was initiated by intraperitoneal injection of one side population(SP)cell derived from a mouse ascites tumor and the host mice died of the ascites tumor. The SP cells were thought to be cancer stem-like cells. Examination by differential interference contrast microscopy revealed that the SP cells were smaller in size(ϕ 27.5µm), and had a higher N/C ratio, sparser and shorter microvilli on the cell surface, and significantly fewer mitochondria, as compared to the non-SP cells(ϕ 30.0µm). These findings could be related to the stemness of the SP cells.