Microarray technology provides a revolutionary macro-genetic and bioinformatic-rich platform for understanding human diseases. DNA microarrays facilitate the study of complex diseases, enabling several observations simultaneously that can become foundations for newer hypotheses-shifting us towards a non-reductionist approach to biological phenomenon. This appears of particular value for scientific and clinical dissection of tumor pathologies. Despite the tremendous potential presented by microarray technology for the investigation of disease, concrete insights and advances that translate to the clinical setting are only recently beginning to be tapped. Here, we discuss specific examples of how microarray technology is being integrated into our ever-evolving approach to clinical disease. We focus on molecular strategies for (a) disease classification, (b) disease outcome, and (c) disease mechanisms.