Breast cancer: 10 separate diseases

Breast cancer should now be thought of as 10 completely separate diseases, reports a landmark study on the disease.

Sorting breast cancer into 10 different types could help predict survival rates, as well as improving treatments by offering more specific drugs for each different type.

Researchers compared breast cancer to a map of the world, with different types of breast cancer currently separated into “continents” for treatment. This new research will allow breast cancer to be split into “countries”, which will help treatment be more precise.

“Breast cancer is not one disease, but 10 different diseases,” said researcher Prof. Carlos Caldas. “Our results will pave the way for doctors in the future to diagnose the type of breast cancer a woman has, the types of drugs that will work and those that won’t, in a much more precise way than is currently possible.”

Scientists decided on the 10 different types by looking at which genes were working overtime in the breast cancer cells and which genes were no longer working properly. They also looked at what kinds of receptor the tumour cells had – for example, if cells have the Her2 receptor then they can be treated with the drug Herceptin.

Around 2,000 frozen breast cancer samples were analysed in this groundbreaking study, published in the scientific journal Nature. However, researchers still need to prove that there are benefits to treating patients according to this classification. This means that it will be at least three years until the study changes the way hospitals and clinics treat breast cancer.

This study could “revolutionise the way breast cancer is diagnosed and treated” says Baroness Delyth Morgan, chief executive of Breast Cancer Campaign. “Being able to tailor treatments to the needs of individual patients is considered the Holy Grail for clinicians and this extensive study brings us another step further to that goal”.