A Paradigm Shift for Ovarian Cancer Detection: Development of a Targeted Mass Spectrometry-Based Assay for Liquid-Based Pap Tests and Cervical Swabs
Abstract
Rationale and Objectives: Early detection is critical to increase the survival rates for women with ovarian cancer. Current clinical tests for women with vague symptoms of or at high risk for ovarian cancer include measuring serum CA-125 levels and performing transvaginal ultrasounds. However, these methods are not adequately sensitive or specific enough to screen the general population. We need to think outside the box if we want to develop a test to detect ovarian cancer in its earliest stage. In our initial OCRP Pilot Award, we proposed a paradigm shift to change the way that women are screened for ovarian cancer. With funding provided by the OCRP, we investigated the standard Papanicolaou (Pap) test as our sample of choice for assay development. The liquid-based Pap test consists of collecting cervical cells from the external cervical opening and placing them into a vial containing an alcohol-based fixative. After processing the cells from the vials and staining them, they are examined by a pathologist to identify the presence of premalignant and malignant cells. The fact that ovarian cancer cells have been identified in liquid- based Pap tests suggests that ovarian cancer proteins and peptides can also traverse the fallopian tube to the cervical opening. Currently, physicians tell their patients that the Pap test is only useful for the detection of cervical cancer, but it cannot detect ovarian cancer. We intend to challenge this dogma by continuing our studies with Pap test samples as outlined in this Teal Expansion Award. The objective of this study is to discover and verify ovarian cancer biomarkers in Pap test fixative samples collected from women up to 2 years prior to their diagnosis of ovarian cancer (pre-diagnostic). We will then develop a highly sensitive test that could be incorporated into a routine Pap test for the detection of cervical cancer and early stages of ovarian cancer. Expansion of Our Original Research Idea: Aims Achieved During Our OCRP FY15 Pilot Award. The 2 years of funding provided by our OCRP Pilot Award enabled us to discover proteins in Pap test fixatives that are unique or present at higher levels in Pap test samples from women with ovarian cancer compared to samples from women with benign gynecological conditions or healthy women. We accomplished the following aims, which we will expand upon in our new Teal Expansion Award: 1. We developed an Institutional Review Board-approved Mock Pap test kit to allow University of Minnesota clinicians to collect samples (a SurePathTM liquid-based Pap test and two cervical swabs) during routine gynecologic exams or prior to surgery. 2. We collected more than 600 Mock Pap tests from women with ovarian cancer, benign ovarian masses, and healthy controls. We used some of these samples for our biomarker discovery experiments. 3. We identified more than 3,000 proteins in Pap tests from women with ovarian cancer, benign ovarian masses, and healthy controls using a highly sensitive mass spectrometry instrument. 4. Importantly, we discovered 30 proteins that were present at different amounts in the Pap tests of women who had high-grade serous ovarian cancer compared to Pap tests from women with benign ovarian conditions and healthy women. 5. We performed targeted assays, called SRM-MS, using a mass spectrometer instrument to specifically seek out and measure the levels of 5 of these 30 proteins among all the proteins in a second set of Pap test samples. Two of the five proteins were present at significantly higher levels in the Pap tests from women with high-grade serous ovarian cancer compared to healthy women. Developing additional targeted assays in this Teal Expansion Award using pre-diagnostic Pap test samples will enable us to detect early-stage ovarian cancer biomarkers in Pap test samples. 6. Of the 2701 proteins that we identified in the Pap test sample of a woman with high-grade serous ovarian c
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 28, 2022
- Source ID
- W81XWH2210486
Entities
People
- Amy P N Skubitz
Organizations
- United States Army
- University of Minnesota