( Certain types of brain cancer cells ca...)Cancer stem cells linked to radiation resistance

The researchers also identified a method that appears to block the cells' ability to activate the repair switch following radiation treatment. This finding may lead to the development of therapies for overcoming radiation resistance in brain cancer as well as other types of cancer, the researchers said.

Working with animal and cell culture models, the researchers found that a specific cellular process called the "DNA damage checkpoint response" appears to enable cancer stem cells to survive exposure to radiation and to switch on a signal to automatically repair any damage caused to their DNA.

"In recent years, people have hypothesized that cancer stem cells are responsible for the resistance of malignant tumors to radiation treatment," said Jeremy Rich, M.D., senior investigator of the study and an associate professor of neurology at Duke. "We have shown, for the first time, that this is indeed the case."

The findings appear Oct. 18, 2006, in the advance online edition of the journal Nature. The research was supported by the National Institutes of Health and a number of philanthropic organizations [complete list below].

The type of cancer that the researchers studied, glioblastoma, is highly resistant to radiation and other forms of treatment and is the most deadly form of brain cancer worldwide. Although aggressive treatments can destroy the majority of the cancerous cells, a small fraction of them remain and often regenerate into even larger masses of tumor cells.

Until recently, scientists knew little about what made these resistant cells different from those that succumb to radiation treatment. It was clear, however, that the cells shared cha
'"/>

Source:Duke University Medical Center