Stem Cells: Therapeutic Implications in Chemotherapy and Radiotherapy Resistance in Cancer Therapy.

Cancer stem cells (CSCs) are transformed forms of normal stem cells within heterogeneous mixture of cancer cells. These are mainly responsible for the recurrence of cancer after treatment because of their ability to develop resistance against chemo and radiotherapy due to various factors such as activation of signalling pathways important for self-renewal, DNA repair capacity, microenvironment and expression of ABC transporters. Targeting these mechanisms as potential factors can eliminate CSCs, which eventually decreases cancer recurrence. This review focuses on the characteristics of CSCs, their role in the development of resistance to chemotherapy and radiotherapy along with the therapeutic potential targets for successful elimination of CSC population.