Optimization Of Mass Spectrometry-Based Proteomic Identification Of Ovarian Cancer Biomarkers From Residual Pap Test Samples

Abstract

Current screening methods to detect ovarian cancer are not adequately sensitive or specific to detect early disease. In contrast, cervical cancer screening with Pap tests has been routinely performed for decades. The liquid-based Pap test involves collecting cervical cells and placing them into an alcohol-based fixative for later identification of premalignant and malignant cells. We hypothesize that proteins shed by ovarian cancer cells are detectable in residual Pap test fixatives by mass spectrometry (MS)-based proteomic techniques. This biospecimen source is ideal for biomarker discovery since the samples are routinely collected, derived from a site near the tumor, and may not contain high abundance proteins that mask potential biomarkers. We have optimized a protocol for obtaining “mock Pap tests” from patients with ovarian cancer and patients with benign or normal conditions. Multiple workflows were tested to determine optimal methods of protein sample preparation. The results suggest that liquid-based Pap tests can be used for the identification of ovarian cancer protein biomarkers.