Psychosocial stress can elicit complex effects on the immune and other systems in cancer patients through mechanisms including the sympathetic nervous system (SNS), the hypothalamic-pituitary-adrenal (HPA) axis, and by other hormones and peptides. These catecholamine changes in the tumor microenvironment trigger a cascade of signaling events that create a highly permissive environment for tumor growth and metastasis. We have demonstrated that elevation of SNS mediators (e.g., catecholamines) in the tumor microenvironment can increase angiogenesis and block anoikis. However, the mechanisms by which catecholamines are delivered to the tumor microenvironment are not well understood. On the basis of our preliminary data, we hypothesize that there is increased tumor innervation in response to chronic stress, which promotes epithelial-to-mesenchymal transition (EMT) and metastasis. In this renewal application, we will examine the mechanisms by which chronic stress contributes to increased innervation and, and examine the resultant biological consequences using well-characterized orthotropic mouse models of ovarian cancer. We will also examine relationships between psychosocial stress factors and nerve density in tumors from patients. Findings from this proposal could lead to identification of novel mechanisms underlying accelerated ovarian cancer growth and therefore may lead to new preventive and therapeutic strategies.