This is considered the largest and most comprehensive study of the genetics of breast cancer to date, and it could offer new hope to patients.
For example, there is the finding that a form of breast cancer may be genetically similar to a type of ovarian cancer. This could result in new treatment options for doctors to consider.
And, while this may be an important road map of the genes that go wrong, some experts caution that the map isn't complete.
"It's like a map that has all the cities and the villages and the towns, but doesn't have all the roads, the bridges and the stop signs," said Memorial Sloan-Kettering Dr. Larry Norton. "So, there's a lot that we have to do to connect the dots."
Breast cancer patients will have to wait for clinical trials and other studies before new drugs become available. That process could take years.