The researchers made an unexpected discovery as they analyzed the newly identified fragile sites. They found that many of those fragile sites were located in regions of the genome that contained inactive genes. "This observation was quite surprising, commented Dr. Robert, because previous studies suggested, on the contrary, that the most active genes were more at risk." Pushing their investigation further, the scientists found that the way in which inactive genes were "wrapped" was what made them most fragile. "Inactive genes are wrapped more tightly than active genes, and our results suggest that this wrapping makes them more vulnerable. This comes as a surprise. Intuitively, one would have thought that this tight wrapping would have provided a greater protection."

DNA damages tend to occur at these fragile sites and they play a key role in cancers. Since the methods that were used for this study can easily be adapted to human cells, this key phenomenon in cancer development could be better understood.

"The research that Drs. Durocher and Robert and their teams have undertaken improves our ability to identify changes in DNA, and increases our understanding of how these changes influence the likelihood of developing cancer," said Dr. Morag Park, Scientific Director of the Institute of Cancer Research, part of the Canadian Institutes of Health Research (CIHR), the Government of Canada's health research agency. "CIHR is proud to support the work of Canadian researchers who are illuminating the mechanisms that lead to formation of cancerous cells, which can lead to preventative therapies as well as more effective treatments for those already afflicted with cancer."

Source: Institut de recherches cliniques de Montreal