Pathways of the heart.

Disease heterogeneity presents a formidable challenge for clinical medicine. We are unlikely to develop successful, targeted treatments unless diagnostic schemes begin to reflect the biological complexity underlying superficially similar disease phenotypes. To address heterogeneity, there is an increasing recognition that realistic disease models need to be built on a foundation of quantitative molecular information.1 Such a “systems medicine” approach should ultimately allow classification into biologically more homogeneous groups, with similar prognosis and treatment response.