Do Cancer Stem Cells propel tumour growth, mediating chemo resistance and radioresistance?

The origin and nature of cancer stem cells (CSC) still remains questionable. In addition not much is known about the reason for their resistance to various treatments and relapse in cancer patients after long treatments of chemotherapy and radiotherapy. To answer all these questions, various researchers have proposed cancer stem cell hypothesis which have two separate but related components. First hypothesis states that CSC originates by tissue stem cells through dysregulation of the normally tightly regulated process of self-renewal. However the second hypothesis states that CSC contains a cellular subcomponent that retains key stem cell properties. These two hypotheses are useful to understand of carcinogenesis and tumour cell biology. The cancer stem cell model suggests that it may be necessary to alter the current thinking in CSC treatment. Eradication of cancers may require the targeting and elimination of cancer stem cells. Thus, one must devise strategies that can selectively kill these cancer stem cells while sparing normal stem cells.