Canadians make breakthrough in how cancer spreads
October 8, 2009
In a world first, Canadian scientists have decoded all three billion letters in the DNA sequence of a metastatic breast cancer tumour and identified the mutations that caused the original tumour to spread.
The landmark study by researchers at the B.C. Cancer Agency is a major step toward unravelling the mysteries of how cancer begins and what makes it move to other parts of the body.
"I never thought I would see it in my lifetime," co-principal investigator Dr. Samuel Aparicio, head of the agency's breast cancer research program, said of the ability to decode the breast tumour's DNA.
Aparicio said the DNA-mapping should help researchers develop new breast cancer treatments based on the genetic makeup of both primary and metastatic tumours.
The B.C. team sequenced the genome of a patient's original breast tumour and one that arose in her pleural cavity (between the lungs and chest wall) nine years later.
"What this study has shown, has proven, is that the primary tumour and the metastatic tumour are genetically distinct – they're not the same disease," added co-principal investigator Dr. Marco Marra, director of the agency's Genome Sciences Centre.
When the researchers looked at DNA in cells from the tumours, they were able to tease out 32 mutations – or spelling mistakes – among the three billion-letter alphabet of the genome.
"What that told us was the tumour had evolved considerably from the primary to the eventual metastasis nine years later," Aparicio said. He said the discovery has big implications for the development of new cancer drugs, which may need to be designed to deal with the various genetic mutations.
"What the new approaches are leading us to now look at are: Can we associate mutations in the tumours with the response to drugs?"
The Canadian Press
Toronto Star
Featured Sponsored Listings