Gene sequence is now commonplace. When Craig Venter announced he had sequenced the human genome ten years ago we all held our breaths. What did this mean for cancer patients? Ten years later it is becoming clearer. Distinguished scientists from many famous cancer cancers have come together to create the Cancer Genome Atlas Network. In a landmark paper published recently in Nature (and reported in the New York Times), they have announced a comprehensive analysis and gene sequencing of over 500 breast cancers. In doing so they have found tens of thousands of genetic mutations in those tumors. This complicated and arcane paper goes through their methodology in detail and it is not easy to follow. Their conclusions are, however. They find that all these mutations converge into a mere four types of breast cancer. This finding has implications not only for understanding cancer but also Darwinian evolution — how mutations result in an evolution of a species into something different. An interesting by-product of their work is that one of the four sub-types shares many genetic characteristics with ovarian cancer. This should have implications for therapy and for understanding how a common precursor of breast and ovarian cancer interacts with the currently observed and very virulent BRCA 1 and 2 inherited forms of breast and ovarian cancer. The Nature paper is a basic science tour de force and should quickly translate into therapies for breast cancer based on the genetics of the tumor. As yet no single new treatment has evolved but it is likely that we will see an entirely new and more rational way of treating first breast, then all cancer, very quickly.