We propose to use a 3D cell culture model containing preadipocytes (fibroblasts) and cancer cells to study how POSTN supports cell survival in the presence of chemotherapy reagents. A 3D cell culture model more accurately mimics in vivo tumor formation and how the cells will respond to treatment. We will also test POSTN in cancer formation, chemosensitivity, and tumor recurrence in vivo with a mouse model. Aim 1. Determine the function of POSTN in OC with a 3D cell culture model. Aim 2. Determine the function of POSTN in tumor formation and OC recurrence using a xenograft mouse model.