Ovarian cancer is a lethal disease that is commonly not detected until advanced stages when it is associated with poor survival. Currently, an effective early screening test does not exist and discovery of a precursor lesion in ovarian cancer has remained elusive. Therefore, there is a need to develop novel diagnostic strategies for early detection of ovarian cancer. The goal of this proposal is to develop a serum-based assay that uses antibodies that recognize molecules made by ovarian cancer cells as a diagnostic tool for early detection of ovarian cancer. There is ample evidence in that ovarian cancer patients produce an immune response, which includes the creation of antibodies, to molecules on the tumors, although the immune response is not effective in killing the tumor. The work proposed here will attempt to identify a panel of antibodies that can discriminate between individuals with and without cancer. The study will be done using serum samples from ovarian cancer patients and age-matched volunteer donors.