Breast cancers found to fall into four main groups, raising hope for more targeted treatments
'Giant step closer' to understanding genetic origins of four subtypes of breast cancer, says expert
Research that mapped 800 breast tumours could lead to more targeted drugs



14:51 GMT, 24 September 2012

Breast cancer falls into four genetically distinct groups, according to the most comprehensive analysis of the disease so far.

Scientists completed the genetic mapping of 800 breast tumours. They looked at the biological details of tumours, rather than focusing primarily on where the cancer arises in the body.

Study co-author Dr Charles Perou, from the University of North Carolina, said the research was 'a near complete framework
for the genetic causes of breast cancer, which will significantly impact
clinical medicine in the coming years.'

The study threw up some surprising findings. It found one of the most deadly subtypes, known as 'basal-like' were more similar to ovarian tumours than other breast cancers.


Screening: Around 48,000 women in the UK develop breast cancer every year. The latest research could lead to more targeted treatments

It opens the possibility for more effective treatment options that target genetic weaknesses of the tumours, perhaps using some drugs already in use.

Study co-leader Dr Matthew Ellis, from the University of Washington, said: 'With this study, we're one giant step closer to understanding the genetic origins of the four major subtypes of breast cancer.

Dr Matthew Ellis

Step closer: Dr Matthew Ellis has led the search for the genetic origins of breast cancer

'Now we can investigate which drugs work best for patients based on the genetic profiles of their tumors.'

The researchers analyzed DNA of breast cancer tumors from 825 patients, looking for abnormalities. Altogether, they reported, breast cancers appear to fall into four main classes when viewed in this way.

One class showed similarities to ovarian cancers, suggesting it may be driven by similar biological developments.

'It's clear they are genetically more similar to ovarian tumors than to other breast cancers,' Dr Ellis said.

'Whether they can be treated the same way is an intriguing possibility that needs to be explored.'

Around 48,000 women in the UK develop breast cancer every year, most of whom are over 50. There is a good chance of recovery if it is detected in its early stages.

Professor Carlos Caldas, from Cancer Research UK, said: 'This comprehensive new analysis of 800 breast tumours is a welcome addition to the wealth of new information about the underlying biology of breast cancer, and will be a precious and valuable resource for cancer researchers.

'This will allow us to further refine understanding of the disease, with the ultimate aim of improving things for those who matter most – people diagnosed with breast cancer.'

Professor Caldas added that the study corroborated the findings of the Cancer Research UK-funded METABRIC study, which revealed breast cancer to be ten separate diseases.

The report is the latest from the federally Cancer Genome Atlas, and was published in the journal Nature.