Abstract B43: A serum protein biomarker signature for the detection of early stages of ovarian cancer

Abstract

Abstract The two bes- known ovarian cancer biomarkers, CA125 and HE4, are neither adequately sensitive nor specific to be used to screen the general population for early stages of ovarian cancer. The purpose of this study was to develop a multiprotein classifier that would combine additional protein biomarkers with CA125 and HE4 in order to increase their sensitivity and specificity. We used the Olink Proseek Multiplex Oncology II panel to simultaneously quantify the expression levels of 92 cancer-related proteins using proximity extension assay technology. We analyzed serum from two institutions: 143 women with early-stage (I/II) ovarian cancer (serous, endometrioid, clear-cell, mucinous, and others) and compared the values obtained to 341 age-matched healthy women. We identified 24 proteins whose relative expression between cancers and controls was significantly different between the samples from the two institutions; therefore, we removed these proteins from downstream analysis. Principle Component Analysis and T-distributed Stochastic Neighbor Embedding separated the ovarian cancer samples from the healthy controls, with minimal misclassification. Data from the Proseek plates for CA125 levels exhibited a strong correlation with previously measured clinical values for CA125 (correlation coefficient of 0.81). CA125 and HE4 were detected at low levels in samples from healthy women, while higher levels were observed in the early-stage ovarian cancer cases. We identified 31 proteins that differed significantly (p < 0.001) between ovarian cancer and healthy samples, several of which are novel serum biomarkers for ovarian cancer. In total, 11 proteins had an estimated area under the ROC curve of 0.70 or greater. CA125 alone achieved a sensitivity of 81.0% at a specificity of 98%. However, by adding three proteins to CA125, we increased the assay sensitivity to 86.2%, while holding the specificity fixed at 98%. In conclusion, our data demonstrate that the inclusion of several protein biomarkers can improve the sensitivity and specificity of CA125 alone for the detection of early stages of ovarian cancer. Validation of this multiprotein classifier is currently under way using serum samples from other institutions. Citation Format: Amy P. Skubitz, Kristin L. Boylan, Timothy K. Starr, Xuan Pu, Qing Cao, Kate Geschwind, Robert C. Bast, Jr., Karen H. Lu, Joseph Celestino, Ashley J. Petersen. A serum protein biomarker signature for the detection of early stages of ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B43.