As well as bringing hope to millions of people around the world because of their potential to cure diseases, stem cells may also be causing tumors, say researchers from Canada and Italy. In two separate studies, scientists discovered that colon (cancer) stem cells were causing colon cancer tumors in mice. The researchers say cancer treatments will have to target cancer stem cells.
You can read about this study in Nature.
John Dick, team leader, University Health Network, Toronto, Canada, said that from a genetic perspective colon cancer is one of the best understood tumors. However, it is still the second most common cause of deaths from cancer in his country. He explains that this indicates that colon cancer cells are not destroyed by current therapies.
In the Canadian study, immune system deficient mice were implanted with human colon cancer cells. Only those cells with CD133 on their surface managed to trigger new tumors (CD133 is a kind of protein).
In the Italian study, at the Istituto Superiore di Sanita in Rome, scientists injected immune system deficient mice under the skin with cells coated with CD133. They also found these cells triggered tumors.
This means that a tiny number of colon cancer cells can trigger a tumor. Most tumors are not initiated in this way. Drugs designed to target just those cells may be more effective, suggest the scientists.
“A human colon cancer cell capable of initiating tumour growth in immunodeficient mice”
Catherine A. O’Brien, Aaron Pollett, Steven Gallinger and John E. Dick
Nature doi:10.1038/nature05372
“Identification and expansion of human colon-cancer-initiating cells”
Lucia Ricci-Vitiani, Dario G. Lombardi, Emanuela Pilozzi, Mauro Biffoni, Matilde Todaro, Cesare Peschle and Ruggero De Maria
Nature doi:10.1038/nature05384
Written by: Christian Nordqvist
Editor: Medical News Today