Cancer stem cells: lessons from melanoma.

The model of cancer stem cells in tumor development states that tumors contain a subset of cells that both self renew and give rise to differentiated progeny. Like normal adult tissue stem cells, cancer stem cells are a minority of the whole tumor and are the only cells that are able to maintain tumor growth indefinitely. In the present review is critically discussed the actually existence of a cancer stem cell subpopulation in melanoma. The self-renewal signaling pathways as well as specific markers like as CD133, ABCB5 and ABCG2 recently identified in putative melanoma cancer stem cells are also discussed.