Differentiation Therapy with Cancer Stem Cells

Copyright: © 2014 Lin CY. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Recent studies have shown that many tumors contain a small population of cells, termed tumor-initiating cells or cancer stem cells (CSCs), that are responsible for tumor progression, metastasis, and resistance to chemotherapy and radiation treatment. This new CSC model has given a new perspective on the origin of cancer and the development of the heterogeneous hierarchy that constitutes tumor populations. Moreover, this finding has shifted an old idea to a novel paradigm that inspires new strategies to fight cancer. For example, increased attention has focused on targeting specific cell surface markers (antigens) contained in these stem cells. So far, the most extensively studied antigen is CD133. New drugs for the treatment of CSCs have also been designed to target cellular mechanisms that regulate cell proliferation, including Bmi-1, Notch, Sonic hedgehog and Wnt signaling pathways. Nonetheless, these attempts are generally quite tissue-specific, making it difficult to extensively target CSCs across tumors to achieve broad therapeutic efficacy.