While actress Angelina Jolie has focused attention on the genetic links to breast cancer, DNA testing for cancer is already a regular occurrence at the London Health Sciences Centre.
It’s estimated approximately 10 per cent of cancers have a genetic link, and in London testing and counselling are done through LHSC’s Medical Genetics Program.
From a tiny vial of DNA, it’s possible to gather clues about who’s vulnerable to cancer with hereditary links.
The genetics program at LHSC receives about 800 patient referrals per year, of those the vast majority of cases fall into two categories – breast and colon cancer.
Karen Panabaker, a senior genetic counsellor, says “Close to 70-75 per cent are breast or ovary related. Maybe another 25 per cent are colon related…It does fall off – I would say less than 10 per cent are related to other more rare cancer syndromes.”
It starts with a blood test, then DNA is extracted and analyzed at a lab, with tell-tale signs showing up in the patient’s genetic sequence.
Alan Stuart, senior technologist with the Medical Genetics Program, says “In this particular spot there’s a ‘typo’ for lack of a better word…In this spot there’s a mistake that’s changed the protein sequence.”
How long it takes to analyze the results of the genetic testing can vary widely, Stuart says.
“Depending on the complexity of the gene it can be anywhere from a week to two months.”
Referrals to LHSC’s Medical Genetics Program are based on a patient’s family history of cancer.
