Swedes behind major cancer breakthrough

Swedish researchers have discovered a new mechanism which repairs damaged DNA. The finding, which was published in the journal Science on Friday, could have major implications for solving the riddles of cancer.

• Mats Sundin in massive kid's health research gift (10 Feb 12)
• Agency to cancer victim: 'go to social services' (6 Feb 12)
• Hot dogs hike cancer risk: Swedish study (14 Jan 12)

"By understanding how a healthy cell works it is also easier to understand what has gone wrong in a cancer cell," said Camilla Sjögren, who led the research at Solna's Karolinska Institute.

The new results focus on DNA, which is replicated every time a cell divides. Up until the splitting process itself, the two bits of DNA are bound together by a protein called cohesin. If the cohesin does not work properly then the two new cells can inherit the wrong number of chromosomes, which is often the case in tumour cells.

Camilla Sjögren's group has now shown that cohesin is also used for reparing damaged strings of DNA, contradicting scientists' previous understanding of the process. Knowledge of the cell's own repair process could be a major step forward in developing anti-cancer drugs.

"We now know that cohesin is important for fixing damaged DNA. The next step for us is to research in more detail what it is about proteins and enzymes that influences the building of cohesin," said Sjögren.

But this new understanding of cohesin's properties is also important within research areas other than cancer. Chromosome defects are the cause of several conditions such as Downs Syndrome.

"As far as Downs Syndrome is concerned, the condition depends on an incorrect distribution of chromosomes. And we know that cohesin is important for making sure that that distribution is correct," said Camilla Sjögren.

Science is one of the world's most prestigious scientific journals and only a handful of Swedish researchers see their results published in it each year.

"When we saw the first results we understood that this is big. It has taken us a long time to make sure that we were right," said Sjögren.