Developmental signalling in maintenance and regulation of cancer stem cells

Tissue stem cells self-renew throughout the life of an organism thereby maintaining tissue homeostasis and prevent cancer. The major signalling pathways such as Wnt, Notch and Sonic hedgehog control the stem cell regulation and their deregulation leads to cancer. Recent evidences showed that there exists a subset of cells within tumour termed as cancer stem cells (CSCs). These CSCs escape the conventional chemo-radiotherapy and further lead to tumour relapse followed by metastasis. This review focuses on the developmental signalling pathways that are involved in the regulation and maintenance of normal stem cells and CSCs. Understanding the molecular mechanism may be useful to specifically target the CSCs while sparing the normal stem cells to reduce tumorigenecity.