Four scientists at British Columbia's Simon Fraser University have helped unlock the genetic code of the deadliest form of breast cancer.

The scientists formed part of an international team that mapped the genomes of more than 100 tumours of triple-negative breast cancer, the largest ever genetic analysis of this type of cancer.

Their research, published in the scientific journal Nature, found that no two tumours were the same, shedding light on why the cancer is so hard to treat.

Dr. Sam Aparicio, study lead, said the research showed that triple negative breast cancer is not just one subtype of breast cancer, but actually extremely complex.

"What's extremely motivating with these findings is the opportunity to design clinical trials for patients with triple-negative breast cancer, so we can explore patient responses to treatment at the genetic level and look at ways to improve therapies and outcomes for patients," he said.

The study suggests that cancer drug treatment used should be tailored to the genetic makeup of a particular tumour, as opposed to a more generalized therapy.

Dr. Samuel Abraham, of the BC Cancer Agency, said the research emphasizes the importance of personalized cancer drug treatment.

"What this likely does is gives us an ability to address the complexity, by actually distinguishing the different kinds of triple-negative breast cancer appropriately," he said.

"It gives us a handle on potentially treating something that has hitherto been very difficult to treat."

Currently, triple-negative breast cancer accounts for 16 per cent of all breast cancer diagnoses and approximately 25 per cent of breast cancer deaths.

Triple-negative breast cancer is considered the most deadly form of the disease because it does not respond well to modern drug therapies.

Triple-negative breast cancer refers to any breast cancer that does not express the genes for estrogen receptor, progesterone receptor or Her2/neu.