Cancer Stem Cells Again

There is an interesting update on cancer stem cells in Science. They write:  

THE CANCER STEM CELL model emerged in the mid-1990s, when stem cell biologist John Dick of the University of Toronto reported that his team had isolated rare cells in the blood of people with leukemia that seemed to play a key role in the cancer. Although such patients' blood teems with aberrant white blood cells, only a few of them were capable of growing into a new leukemia when injected into mice. Those cells appeared to be misguided versions of the normal adult blood stem cells that differentiate into mature blood cells. Like normal stem cells, the cancer stem cells carried distinctive surface proteins and were self-renewing: They could divide to produce both a regular cancer cell and a new stem cell.

 Now many researchers have examine the stem cell model and there are reasons for its validity. We have argued for Prostate Cancer and one suspects for hematologic cancers such as MDS. The article focuses on Weinberg at MIT and his new company where the authors state:

Verastem's strategy is to screen approved drugs and other chemicals for their ability to block focal adhesion kinase (FAK), an enzyme that helps tumor cells stick to each other and also helps cancer stem cells survive. In the body, Weinberg believes, blocking FAK kills cancer stem cells directly and also makes it harder for these rare cells within a primary tumor to travel through the bloodstream and seed metastases. 

 It should be interesting to see how this develops. Perhaps our understanding of the stem cell is not mature enough. It has also been argued that the stem cell uses exosomes to cause growth in other cells. There is still a great deal to understand.