What are cancer stem cells?

In recent years, there has been increasing evidence demonstrating that melanoma, as well as other solid tumors, contain a subpopulation of cancer stem cells (CSCs). CSCs are rare cells within tumors with the ability to self-renew, drive tumorigenesis, and give rise to a phenotypically diverse tumor cell population. They are considered the source of the primary tumor mass and are thought to be responsible for drug resistance and cancer recurrence. Experimental evidence supports the existence of CSCs in leukemia and melanoma, as well as in breast, brain, colon, pancreatic, and ovarian cancer. Although controversy exists regarding the location of melanoma stem cells in the skin, it has been hypothesized that most melanomas arise from mutations that accumulate in a common precursor CSC, which subsequently drives the establishment of primary and metastatic lesions. This CSC-like precursor is thought to be responsible for the metastatic process, while the less stable progeny are unable to spread locally or distantly. Although definitive markers are still lacking for melanoma CSC, CD133, ABCB5, and ABCG2 have been identified as potential markers.


Sabatino M, Stroncek DF, Klein H, et al: Stem cells in melanoma development, Cancer Lett 279:119–125, 2009.

La Porta C: Cancer stem cells: lessons from melanoma, Stem Cell Rev 5(1):61–65, 2009.

Frank NY, Schatton T, Frank MH: The therapeutic promise of the cancer stem cell concept, J Clin Invest 120:41–45, 2010.