Abstract C29: Combination of SP17 with CA125 serologic measurement for detection of ovarian cancer

Abstract

Abstract Ovarian cancer (OC) is a serious healthy issue for women worldwide, ranking second for mortality rates among gynecological malignancies. CA125 (MUC16) is the only available biomarker to monitor disease and treatment response in OC but it suffers from poor performance for diagnostic purposes. As a consequence, increasing efforts are being made for the identification of novel tumor biomarkers to improve CA125 test specificity and sensitivity. More than 30 serum biomarkers have been studied alone or in combination with CA125. We have previously shown that SP17, a member of the cancer/testis antigen (CTA) family, is a potential biomarker that allows for the discrimination of the normal ovary from OC cells and for the tracking of OC disease in a xenograft mouse model. Here we hypothesized that SP17 serum levels could be exploited as a diagnostic test to detect early lesions of OC and to discriminate between malignant and benign lesions. We analyzed SP17 expression in primary ovarian tissues from ovarian cancer patients, benign ovarian lesions and healthy subjects through RT-PCR and immunohistochemistry. SP17 and CA125 levels were measured in the sera of the same subjects by ELISA. We found that SP17 expression was restricted to OC cells at the transcriptional and translational levels, and that the measurement of SP17 concentration in the serum afforded accurate discrimination between subjects with different prognoses allowing for predicting overall survival time. SP17 assay alone was superior to CA125 in discriminating between ovarian cancer and benign ovarian tumors: combining SP17 and CA125 assays, we obtained 96% sensitivity, 89% specificity and 97% PPV. SP17 is a novel serum biomarker for ovarian cancer. SP17 serum measurement in combination with CA125 affords improved positive predictive value for diagnostic purposes. Citation Format: Maurizio Chiriva-Internati, Leonardo Mirandola, Yuefei Yu, Marjorie R. Jenkins, Everardo Cobos, Jose A. Figueroa, Hans W. Nijman, W. Martin Kast. Combination of SP17 with CA125 serologic measurement for detection of ovarian cancer. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr C29.