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Researchers Identify Cancer Stem Cell for Brain Tumors
A research team at the Hospital for Sick Children (HSC) and the University of Toronto (U of T), led by Dr. Peter Dirks, has identified for the first time a cancer stem cell in both malignant and benign brain tumors. This discovery may change how brain tumors are studied and how this deadly condition is treated in the future. The research was reported in the journal Cancer Research.
"The discovery of a cancer stem cell for brain tumors means that only a small number of cells in a brain tumor have the ability to drive tumor growth. Many current cancer therapies may fail because they do not kill the cancer-sustaining stem cells. We now have to work on designing therapies that will attack these stem cells," said Dirks, an HSC neurosurgeon and assistant professor of Neurosurgery at U of T.
Brain tumors are the leading cause of cancer mortality in children and remain difficult to cure despite advances in surgery and drug treatments. In adults, most brain tumors are also amongst the most sinister of cancers with formidable resistance to most therapies.
"We found that cancer stem cells from different tumor types, from aggressive malignant tumors to more slow-growing benign ones, share similar properties to each other as well as to normal brain stem cells. This suggests that mutations that lead to cancer formation may have originated in the brain´s own small numbers of stem cells," said Dr. Sheila Singh, the paper´s lead author, an HSC neurosurgery resident and U of T graduate student.
The biology of the brain tumor stem cell may also shed light on metastases (tumor spread). The non-stem cells in the tumor may break off and spread, but may not be able to grow at distant sites. "It is possible that only the tumor stem cells will be able to grow at distant sites. If this is indeed the case, then the destruction of tumor stem cells may also be important for preventing metastatic disease," added Dirks.
The next stages of this research involve genetic studies of the purified cancer stem cells to find new genes that are critical for cancer stem cell growth. The identification of these genes is important for determining new targets for brain tumor therapy. Dirks´ laboratory is also investigating whether a patient´s cancer stem cells alone can cause growth of the patient´s tumor in a mouse. If the tumor resembles the patient´s original tumor, this may lead to a mouse model for the tumor type.
SOURCE: Cancer Research, September 15, 2003
Behind the Cancer Headlines, September 16, 2003