Hematopoietic normal and cancer stem cells: Drugs and toxicity

Stem cells occur in many somatic tissues of multicellular organism and are important participants in their physiology. Stem cells have three distinctive properties: 1- self-renewal, 2- the potential to proliferate extensively and 3- capability to develop into multiple lineages. Every time a stem cell divides, it makes one exact copy and one progenitor cell. Progenitor cells have finite division capacity and ultimately differentiate into mature cell typesunder special groth factors. Researches show that there are many similarities between normal stem cells and cancer stem cells, so it seems that stem cells have a role in cancers of hematopoietic system, brain, and breast. Given these similarities, it is possible that cancer stem cells arise by mutations from normal stem cells because both of them are in Go phase of cell cycle. Studies have shown that conventional chemotherapy methods for treating blood-based cancer target cells that are metabolically and proliferatively active, have adverse effects on normal stem cells and hematopoietic growth factors. Therefore these cancer treatments fail to eliminate cancer stem cells and allow regrowth of the tumor. It is suggested that developing novel compounds and therapeutic strategies may help in selectively target cancer stem cells specially their surface markers because they eradicate tumors more effectively than current treatments.