We are discovering new drug targets for cancer using a combination of genomic and functional assay technologies. As part of our discovery and validation process we use DNA microarrays to determine the patterns of gene expression in normal tissue, primary tumors and metastatic tumors across a cancer patient population. Tens of thousands of genes, including cancer genes discovered by highly sensitive gene profiling technology, are placed on our DNA microchips. Our DNA microarray technology is highly sensitive and reproducible, allowing us to assay laser capture microdissected material from human biopsy samples. We analyze differential gene expression patterns in the cancer patient population using new clustering approaches. These patterns are, in turn, analyzed against our database of gene expression profiles obtained from cell lines in which pathways have been manipulated, and pathways that are altered in patients are identified. We then further evaluate selected differentially expressed genes, along with their pathways, as potential targets for diagnostic and therapeutic approaches using functional analysis.