An almost perfect picture of the genetic events that cause breast cancer have been discovered by scientists. The findings are an important path leading to the development of new drugs used in the treatment of the disease, according to Cancer Research UK.

An international team of scientists worked on a study, which is the largest of its kind, to look at 3 billion letters of people's genetic code in 560 breast cancers. The findings discovered 93 sets of genes that if mutated can cause tumours. The scientists believe that this is the definitive list, although there may be some mutations. The roles of viruses or other microbes have not been completely examined, states the study published in Nature.

Professor Mike Stratton who led the study said: "There are about 20,000 genes in the human genome. It turns out, now we have this complete view of breast cancer - there are 93 of those [genes] that if mutated will convert a normal breast cell into a breast cancer cell. That is an important piece of information.

"We hand that list over to the universities, the pharmaceuticals, the biotech companies to start developing new drugs because those mutated genes and their proteins are targets for new therapeutics," he told the BBC.

"There are now many drugs that have been developed over the last 15 years against such targets which we know work," said the director of Cambridge-based Sanger Institute.

However, the new drugs that will be developed could take at least 10 years before they are available for use by patients: "Cancers are devious beasts and they work out ways of developing resistance to new therapeutics so overall I'm optimistic, but it's a tempered optimism," said Stratton.

Every year around 60,000 people are diagnosed with breast cancer in Britain, or the equivalent of one person every 10 minutes. According to Breast Cancer Care, 1 in 8 women in the UK will develop the disease in their lifetime.