Scientists are saying they now have an almost complete understanding of the genetic events that cause breast cancer, calling it "a milestone moment".
The study, published in Nature, claims to help unlock new ways of treating and preventing the cancer, which some scientist hail could bring us a step closer to personalised health care.
To find out the cause of the disease, scientists need to know what goes wrong in our DNA that makes healthy tissue turn cancerous.
Mutations, leave scars on our DNA, known as mutational signatures.
The research team looked at 3 billion letters of people's genetic code in 560 breast cancers. They found 93 sets of protein-coding cancer genes that carried probable driver mutations, and 12 types of damage that cause mutations in the breast.
Some of these have been described before, but this list is expected to be conclusive.
The data says 60 percent of the mutations driving cancer are found in just 10 genes, but on the other hand there are mutations so rare that it is unlikely there will be any financial incentive to develop treatments.
Some mutations are related to family risk, but most are unexplained.
Der Emma Smith from Cancer Research UK told the BBC the research could be "important stepping stones" to developing treatment for patients, effectively "boosting the number of people who survive cancer".