than Markers : Biological Significance of Cancer Ther m Cell - Defining Molecules

ownload ll populations within an increasing array of solid tumors, labeled cancer stem cells (CSC) or tumoring cells (TIC), have the ability to differentiate, self-renew, and replicate the original tumor in vivo. To hese cells have been distinguished from the bulk-tumor population by the expression pattern of celle proteins (e.g., CD24, CD44, CD133) and cellular activities, such as the efflux of Hoechst dye or aldedehydrogenase activity. Recent data have shown that these markers are inducible by exposure to ncer agents; this finding highlights not only the potential fluidity of the CSC compartment, but also nctionality of these markers. The involvement of CD44 in invasion, adhesion, and metastasis, or the f CD24 in modulation of src, FAK, and GLI1 are examples of these relevant roles. Instead of looking at the marker expression in these populations, we hope to clarify the biologically significant roles these solely markers and activities play in tumor progression, metastases, and as possible targets for therapy. Mol Cancer Ther; 9(9); 2450–7. ©2010 AACR.