Cancers do not exist in isolation but interact with and often depend upon chemical and epigenetic signals from surrounding cells. Culture and assay systems have been developed by various groups that allow these interactions to be studied. This project will examine the links between stromal cells and cancer cells in prostate and bladder cancers and specifically examine the functional significance of various cell surface molecules, secreted cytokines and chemokines, antigen expression, epigenetic mechanisms, and processes for perturbing these interactions that may be able to be translated into