New biological mechanism that causes cancer found

In a landmark study, researchers have found that unusual changes in the instructions for how the genome folds up on itself could be a completely new biological mechanism that underlies cancer.

By studying brain tumours that carry mutations in the isocitrate dehydrogenase (IDH) genes, the researchers discovered that the changes in instructions target key parts of the genome, called insulators, which physically prevent genes in one region from interacting with the control switches and genes that lie in neighbouring regions.

When these insulators run amok in IDH-mutant tumours, they allow a potent growth factor gene to fall under the control of an always-on gene switch, forming a powerful, cancer-promoting combination.

The findings point to a general process that likely also drives other forms of cancer, the study said.

"This is a totally new mechanism for causing cancer, and we think it will hold true not just in brain tumours, but in other forms of cancer," said senior author Bradley Bernstein, professor of pathology at Massachusetts General Hospital in the US.

"It is well established that cancer-causing genes can be abnormally activated by changes in their DNA sequence. But in this case, we find that a cancer-causing gene is switched on by a change in how the genome folds," Bernstein noted.

The study appeared in the online issue of the journal Nature.