DNA analysis brings scientists step closer to ‘complete picture’ of breast cancer

An analysis of the complete genetic code of hundreds of breast tumours could lead to more personalised care for patients, according to an international team of scientists.

The results reveal that patients’ tumours may be highly individual. And experts have said that the new findings offer a more comprehensive view of breast cancer. 

“This study brings us closer to getting a complete picture of the genetic changes at the heart of breast cancer and throws up intriguing clues about the key biological processes that go wrong in cells and drive the disease,” said Dr Emma Smith, Cancer Research UK’s science information manager.

The studies, led by scientists at the Wellcome Trust Sanger Institute, analysed the complete genetic code – or genome – of 560 breast tumours. 

The analysis uncovered five genes newly associated with the disease.

And the results, published in two papers in the journals Nature and Nature Communications, provide evidence that breast tumours can differ greatly between patients.

The team searched for gene faults (mutations) that encourage the disease to grow, as well as characteristic patterns of DNA faults – known as mutational signatures – in each tumour.

They found that women whose tumour cells carried faults in the BRCA1 and BRCA2 genes – which increase the risk of developing breast and ovarian cancer – had different genetic profiles that were distinct from other breast tumours.

Dr Serena Nik-Zainal, who led the team of researchers, said: “In the future, we’d like to be able to profile individual cancer genomes so that we can identify the treatment most likely to be successful for a woman or man diagnosed with breast cancer. It is a step closer to personalised healthcare for cancer.”

Cancer Research UK’s Dr Smith added that this type of large-scale research was vital for developing new treatments.

“Understanding these underlying processes has already led to more effective treatments for patients,” she said.

“So genetic studies on this scale could be an important stepping stone towards developing new drugs and boosting the number of people who survive cancer.”

Dr Ewan Birney, from the European Bioinformatics Institute and who also worked on the study, said that analysing the complete genetic code in this way uncovered “some new reasons why breast cancer arises”. He added that the research gave “an unexpected way to characterise the types of mutations that happen in certain breast cancers”.

Professor Sir Mike Stratton, director of the Wellcome Trust Sanger Institute, said discovering gene mutations is “crucial” to understanding the causes of cancer and coming up with better treatments.

“This huge study, examining in great detail the many thousands of mutations present in each of the genomes of 560 cases brings us much closer to a complete description of the changes in DNA in breast cancer and thus to a comprehensive understanding of the causes of the disease and the opportunities for new treatments,” he added.