New results from a study defining breast cancer as a collection of 10 different diseases have shed light on why some patients are more likely to die than others.
Scientists involved in the Metabric study identified 40 mutated genes that cause tumour progression, only a fraction of which were previously known to play a role in breast cancer development.
One of the more commonly mutated genes, known as PIK3CA, was linked to lower chances of survival for three of the 10 breast cancer subgroups. This may explain why drugs targeting PIK3CA only work for some women, say the researchers.
The findings, published in the journal Nature Communications, are expected to help pave the way for new targeted treatments and diagnostic tests.
Lead author Professor Carlos Caldas, a Cancer Research UK scientist based at Cambridge University, said: “The Metabric study mapped out the genetic blueprints for breast cancer. And these new results give us even more detail about which genetic faults could be linked to how different types of breast cancer develop and progress.
“The information could in the future help design clinical trials for breast cancer patients, or give researchers more flags to look out for in liquid biopsies, a type of test used to detect genetic material in the blood that is released by dying cancer cells.”
Metabric (Molecular Taxonomy of Breast Cancer International Consortium) recruited 2,000 breast cancer patients who donated tumour samples so that their genetic make-up could be analysed.
Its landmark findings, published in the journal Nature in 2012, showed that breast cancer was effectively not one but 10 different diseases.
Professor Peter Johnson, Cancer Research UK’s chief clinician, said: “Our research continues to highlight just how complicated cancers are, but we are managing to solve these puzzles faster than ever. This study gives us more vital information about how breast cancer develops and why some types are more difficult to treat than others, and this information is a great resource for researchers all over the world.”