Failure to communicate underlies cancer and other diseases. Tissues are comprised of a society of diverse cell types that similar to human societies must communicate properly to maintain normal function, peace, tranquility and good health. The failure to communicate properly underlies most tissue dysfunctions and disease. The laboratory studies how the chemical signals (polypeptide growth factors and cytokines) in the local tissue environment control growth and specialization of different cell types of the prostate, the liver, the vascular system and neural tissue. These signals determine the normal development and function of the tissues while aberrations result in tissue dysfunction and diseases, such as cancer, stroke, atherosclerosis, liver, and neural disease. These signaling systems which are comprised of a signal polypeptide from one cell type and a reception system on another are the basis for communication among cells in tissues, but also serve as sensors of signals like hormones and nutrients that come from outside the tissues. The cellular reception system for many signal polypeptides consists of a transmembrane protein whose external domain interacts with signal polypeptides and an intracellular domain which is a protein kinase enzyme which activates metabolic pathways that control cell growth, function, and gene expression.