Made-in-B.C. test determines which parent passed on gene linked to increased cancer risk

A laboratory technician holds a blood sample in Germany.

Researchers at BC Cancer are expanding access to a new test that will help trace the origin of the 15 per cent of cancers that are linked to gene mutations.

British Columbians diagnosed with certain cancers are already offered a blood test that shows whether their disease was inherited. Now, if that test is positive, they will be offered an additional test that will determine if their cancer mutation came from their mother’s or father’s side of the family.

Dr. Kasmintan Schrader, co-director of BC Cancer’s hereditary cancer program and one of the scientists behind the test, explained how knowing which side the gene came from can be helpful.

“If you can know quickly that it came from, say, mom’s side of the family, that means you can quickly go and reach out to that side of the family to understand their chances of carrying the same risk, and whether or not they can reduce that risk through screening, preventative surgeries, or other ways to reduce their cancer risks,” said Schrader.

When Angela Lee’s brother Nelson was diagnosed with pancreatic cancer last summer, the test determined he inherited the gene from his father.

“When we found it was paternal inheritance, we reached out to anybody on my father’s side of the family, my aunt’s family, and said anybody want to be tested? Because potentially their children can also inherit it,” said Angela, who was relieved to test negative for the gene mutation that ultimately took her brother’s life.

Schrader says the test provides more than just information about risk.

“Sometimes this can impact their actual clinical recommendations. In certain genes and certain syndromes, if you get the variant from dad, it predisposes to lifelong screening, needing to look for tumours that might develop. Whereas if you inherited it from mother, you would not have this risk and you would be more off the hook,” said Schrader.

A partnership between the BC Cancer Foundation and Genome Canada will allow any British Columbian found to have a genetic predisposition to certain cancers to get the additional test to determine which side of the family the gene mutation came from.

It will be the first large-scale clinical application of the made-in-B.C. blood test.

“By having a better understanding of the inheritance of these variants, it means that we can use our precious health-care resources and direct our attention to the side most at risk,” said Schrader.

Nelson Lee lost his battle with pancreatic cancer in March. By having the genetic test before he died, he gave his extended family valuable information that could help them in the future.

“I think it’s great,” said his sister Angela. “Technology now is amazing. And the more we know, the better.”