Cancer is also essentially a disease of the whole organism.
Thus, while in vitro studies have been tremendously important for the discovery and analysis of growth-modulatory signaling pathways and their regulation by gene expression, a complete understanding of cancer genetics requires some studies that involve the intact animal. The studies focus on cancer of the liver, pancreas, and mammary gland, and employ analytical techniques ranging from gross pathological to molecular examinations of animals, tissues and tumors. My goal is to synthesize the results of this diverse set of experimental approaches into an explanation of how, within the context of a living organism, genetically altered cells give rise to the complex disease of cancer. Pancreatic tumor pathogenesis reflects the causative genetic lesion.