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The latest buzzword (or, rather, words) in the cancer research world is “cancer stem cells”. These stem cells are thought to exist in tumours, and the theory goes that they are the reason that many cancers reoccur and medications fail. But what are these stem cells really, and how are they going to help us understand and fight cancer?
Stem cells are, by definition, cells that are capable of self-renewal (when they divide at least one of the two cells remains a stem cell), and are capable of transforming into other cell types. We have small reserves of stem cells in our body, for example in the bone marrow we have stem cells that produce blood, or in the muscle we have stem cells that form new muscle fibers when we exercise or damage our muscles.
In cancer, it has been proposed that a similar small reservoir of cancer stem cells exists within the tumour, and these cells are not always capable of being targeted by chemotherapies. Thus, drugs may cause the tumour to shrink, but cancer stem cells may still remain and produce new tumor cells. Furthermore, if these stem cells which survive, pick up a new mutation that renders them immune to the chemotherapy, the tumour becomes chemotheraphy-resistant and continues to grow. Therefore, the answer does not only lie in finding drugs that can attack tumors and reduce their size, but in also finding a way to attack a potential source of the tumour: cancer stem cells. Similar to a video game, you don’t win by attacking the little guys, you win by attacking the big guy at the end of the game.
Because stem cells could be the key to unlocking the secrets of fighting cancer, extensive research is now going into understanding and fighting cancer stem cells. Researchers are beginning to further understand the mechanisms that allow cancer stem cells to be resistant to chemotherapy. These resistant properties, which differ from normal cells, may even be used to develop targets for future drugs aimed at cancer stem cells.
Many thanks to Tim Pierpont for suggesting the topic of this blog post and providing additional information! For a short video on cancer stem cells made by the Canadian Stem Cell Foundation, watch the video below.
Image credit: http://www.verastem.com/research/