Although rapid responses or long disease free intervals can be retained in advanced stage cancer either by conventional treatment strategies or targeted therapies; cure is seldom if ever is obtained. Recent advances in tumor biology have succeeded in identifying a minor tumor cell subpopulation which have extraordinary capabilities for treatment resistance against various treatment strategies utilizing chemotherapeutic agents and radiotherapy. These cells carry stem cell like properties such as ability to initiate tumor by themselves, self renewal and ability to differentiate into heterogeneous cancer cell lines. In this review , survival and metastatic capabilities of cancer stem cells (CSCs), resistance mechanisms against chemotherapeutic agents are summarized . Novel therapeutic strategies developing against these resilient cell group such as agents specifically designed for targeting survival pathways and intracellular metabolism of CSCs are also discussed.
Keywords: Cancer stem cell (CSC),Drug Resistance,Therapy