What is precision medicine? This term refers to the diagnostic strategies that seek to identify individual differences in therapies that take those individual differences into account. This approach is not new. For example, blood typing has long been used in blood transfusions. More recently, tissue typing is being used to guide organ transplantation. The tremendous success of the Human Genome Project set the stage for dramatically expanding this approach. We now know the entire sequence of the human genome and we can rapidly identify variations in DNA sequences between individuals. In addition, the growth of the computer industry has enabled the collection and analysis of tremendous amounts of information.

Together, these advances have spurred the Precision Medicine Initiative. The goal of this initiative is to identify differences between individuals that will allow more accurate and rapid diagnosis of diseases. Initially, this will focus on cancer. And in the longer term, it will focus on other diseases as well. Cancers are largely a consequence of mutations that have occurred during the courses of our lives. In some cases, mutations that we inherit from our parents may also contribute to cancer risks. As cancer grows, a single tumor may contain cells with many different distinct mutations.

The initiative will involve 1 million or more volunteers. Participants will be asked to share their biological information, including cells, blood samples, DNA and RNA sequence, metabolites, as well as behavioral data, and their health records. This information will be correlated with health outcomes and therapeutic interventions to identify indicators of disease, disease risks, and effective therapies that can be tailored to those particular individuals. The large number of people who participate in this project will enable researchers to investigate rare conditions or mutations that may point to important new research directions.

Observing the progression of cancer is important for several reasons. First, targeted anti-cancer therapies are being developed and some of these have had spectacular results. These successes depend on understanding the genetic changes that occur during the growth of specific cancers. Furthermore, detailed knowledge of mutations that cause cancers may aid in better diagnosis and treatments for specific cancer subtypes. Finally, the diversity of tumors means that cancer cells may initially be susceptible to particular therapies, but become resistant over time. In the long-term, the Precision Medicine Initiative will work to increase our ability to better protect the risks of other diseases, understand their mechanisms, and design effective therapies for individual patients.