Canadian docs discover new gene mutation linked to breast cancer risk
Extended interview: Global’s Heather Yourex talks with research author Dr. Mohammad Akbari from Women’s College Hospital via Skype from Toronto.
TORONTO – Angelina Jolie candidly shared her story of getting a double mastectomy after testing positive for the BRCA gene mutation. The anomaly put her at higher risk of a breast cancer diagnosis –now, new Canadian research has identified another gene mutation that’s tied to breast cancer in Polish and French Canadian women.
Scientists out of Women’s College Hospital say mutations in a gene called RECQL could be a predictor of increased breast cancer risk in these groups of women. Their findings were published Monday in the journal Nature Genetics.
“The chance of being diagnosed with breast cancer if somebody carries a mutation in RECQL is estimated to be 50 per cent. It’s very comparable with the risk in BRCA 1 and 2 gene mutation carriers,” Dr. Mohammad Akbari, a co-author on the study, told Global News.
“The risk of being diagnosed in the general population is 10 per cent. If someone carries the mutation, her risk is five-fold more. Her risk jumps,” he warned.
The Toronto researchers collaborated with their peers in Poland and at Montreal’s McGill University to comb through about 20,000 different genes in 195 cancer patients.
The scientists say that about 10 per cent of all breast cancer cases are hereditary, but ony half of all breast cancer susceptibility genes have been identified.
They zeroed in on the two populations – women in Poland and French Canadians in Quebec who had breast cancer and a history of the disease in their families. The two communities are considered “founder populations,” which means they’re genetically homogenous. None of the women had a mutation in BRCA 1 or BRCA 2 genes, though.
RECQL, like the now infamous BRCA genes, are dubbed caretaker genes. They’re responsible for maintaining the integrity of our genome, so they repair any defects in our DNA. Once these genes mutate, the defects accumulate making cells prone to cancer.
After conducting genome sequencing – by sifting through millions of variations – in the breast cancer patients, they found a similarity: a mutation in RECQL. They duplicated their findings by studying another 25,000 patients and their healthy peers from these two populations.
Akbari’s next steps are to study the susceptibility of the gene mutation in other populations.
Mutations in the BRCA gene, for example, are in 12 per cent of the Jewish population and up to eight per cent in the Caucasian population. He says that 25 per cent of the Bahamian population carries the BRCA mutation.
For now, he suggests that the RECQL gene should be added to gene panel tests for breast cancer, the same way BRCA 1 and 2 are. Right now, commercial tests contain about eight to 15 genes – Akbari says RECQL should be within the Top 4 in priority.
“Finding genes that increase risk is important in terms of finding people who are at risk, but it’s more important to find targeted treatment for these individuals, too,” he said. BRCA 1 and 2 mutation carriers respond well to specific chemotherapy drugs, for example.
Women with the BRCA mutation typically have to consider preventative surgery, such as a bilateral mastectomy and oophorectomy (removal of ovaries). Akbari says that women who test positive for the gene mutation should consider the mastectomy but that it’s too soon to say about removing their ovaries.
The doctors haven’t studied how RECQL gene mutations could tamper with ovarian cancer risk.
Their full findings can be read here.
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