Prostate cancer autoantibodies - applications in diagnosis, prognosis, monitoring disease progression and immunotherapy

Although PSA testing is widely used in prostate cancer diagnosis, it remains an imperfect assay due to its lack of accuracy. While several urine or tissue-based gene expression assays are available to identify patients with higher risk of adverse disease and to aid in deciding treatment options, there is still a critical need for reliable biomarkers to monitor disease progression and treatment response. Autoantibodies (AAbs) produced by the humoral immune response against tumor associated antigens offer an attractive alternative, as they target a wide variety of prostate cancer specific antigens and can be collected by using clinically non-invasive methods. Herein, we review the transition from traditional methods that identify individual AAbs to high throughput approaches that detect multiple targets simultaneously in patient sera. We also discuss how these approaches improved the sensitivity and specificity of AAb detection and enhanced prostate cancer diagnosis and prognosis. Cancer vaccines offer potential as a novel therapeutic strategy in their ability to stimulate both cell-mediated and antibody-mediated cytotoxic responses. Ongoing efforts aim to identify immunotherapy targets that also stimulate a strong antibody response, since antibodies activated by the anti-cancer humoral response can eliminate cancer cells effectively via several distinct mechanisms. Autoantibodies are useful not only for the diagnosis of prostate cancer, predicting disease progression, and tracking response to treatment, but can also be harnessed as therapeutic agents for prostate cancer treatment.