Progress towards personalized medicine.

Personalized medicine is the tailoring of therapies to defined subsets of patients based on their likelihood to respond to therapy or their risk of adverse events. The advent of improved genomic tools has greatly hastened our understanding of the molecular pathology of diseases, enabling us to redefine disease at the molecular level. The development of molecularly targeted therapies, coupled with improved diagnostic criteria, holds the promise of delivering a new paradigm in drug development. But how far have we come, and how close is personalized medicine to delivering on its promise?