When discovered at stage I ovarian cancer is curable in 90% of the cases using surgery and chemotherapy. There are 21,000 new cases per year of ovarian cancer however 75% of those cases are diagnosed at stage III or IV and their 5-year survival is about 20%. This results in about 14,000 deaths per year in the US. About 1 in 200 women in North America carries BRCA1 or BRCA2 mutations and 5 million women with a family history of ovarian cancer in a first or second degree relative. Women in these categories who are at higher risk of ovarian cancer would clearly benefit from a screening test and therefore represent the communities that would benefit from this project. A screening test for ovarian cancer will change the approach to healthcare delivery by reducing stage of ovarian cancer at diagnosis to stage at which it is more likely to be curable. We developed a high-throughput proteomics technology we call "Epitomics" for (epitope-omics) in which we immunoselect thousands of phage displayed antigens from cDNA libraries made from RNA from ovarian cancer tissue and cells. We used protein microarrays as a massively parallel immunoassay system to identify the proteins coded by the T7 bacteriophage cDNA libraries that bind to antibodies specifically in the serum of ovarian cancer patients and not to antibodies present in women with benign gynecological diseases. We propose to validate these biomarkers using in vitro synthesized proteins using immunoassays on Luminex bead arrays. Our hypothesis is that it requires panels of biomarkers to accurately distinguish patients with ovarian cancer from those with gynecological benign diseases. Most people in the biomarker field would agree with this hypothesis. We will synthesize proteins in vitro using PCR templates from our selected biomarker bacteriophage clones that we have shown are tumor antigens reacting with antibodies specifically in the serum of ovarian cancer patients. We will validate these biomarkers using sera from early and late stage ovarian cancer. In addition, to ensure the specificity of the diagnostic test we are developing we will assay these biomarkers against sera from women with benign gynecological diseases, autoimmune diseases, and women with other cancers. However, if a fraction of patients are still misclassified using these biomarkers we will use additional approaches such as full length recombinant proteins of the tumor antigens. If necessary alternative approaches will be pursued targeting autoantibodies that are formed against tumor antigens that are overexpressed or mutated by tumor cells. These approaches should provide us with a sufficiently robust panel of antigen biomarker analytes for a bead array assay for the early detection of ovarian cancer. The focus of this project is to translate our large scale immuno-proteomics discoveries of tumor associated antigens into Luminex bead array assays to detect serum autoantibodies for the detection of early stage cancer of the ovary in high risk women and women with a family history of ovarian cancer.
The goal of this project is the final refinement of antigen biomarkers from a large scale proteomic screen so as to employ peptide antigens for the detection of ovarian cancer at an early stage. We are focusing on the most dangerous form of ovarian cancer serous adenocarcinoma, which is often diagnosed at a late stage that is difficult to treat successfully. A blood test to detect antibodies against cancer antigens is a laboratory format for a diagnostic test that can readily be implemented in a clinical setting in order to identify this disease at an early and 95% curable stage.