Prospective identification of cancer stem cells with the surface antigen CD133

Cancer cells do not share equal tumor-initiating potential. Only cancer stem cells (CSCs) can initiate cancer, which is important clinically because they should be eradicated to treat cancer patients. The purpose of experimental methods for identification of CSC is to isolate CSCs among various kinds of cancer cells in cancer masses. To identify CSCs, cancer masses derived from patients should be dissociated into single cells. Dissociated cells are classified into several groups according to expression status of one or several surface proteins using magnetic cell sorting (MACS) or fluorescence-activated cell sorting (FACS) methods. Sorted cells are cultured in a specialized culture medium for stem cells or inoculated into the primary cancer site of immunodeficient mice. In this chapter detailed experimental methods will be described and glioblastoma will be used as an example of solid cancers.