B-368 WomEC, a novel diagnostic test for the detection of endometrial cancer in uterine fluid

Background Endometrial cancer is the first most common gynecological cancer in high income countries. Abnormal uterine bleeding is the main symptom to initiate the multistep diagnostic process, which relies on the observation of tumor cells in a minimally invasive endometrial pipelle biopsy. Endometrial pipelle biopsies are commonly used for diagnosis but lead to inconclusive results in up to 30% of the cases due to insufficient presence of cellular material. Previous research allowed us to understand that after processing these biopsies, we can obtain the uterine fluid, an outstanding source of biomarkers for endometrial cancer diagnosis. In this study, we used the uterine fluid to develop WomEC, an immunoassay-based endometrial cancer diagnostic test. Methods Endometrial cancer diagnostic biomarkers were discovered, verified and validated in five independent clinical case-control retrospective cohorts including 358 patients (217 case; 141 control). Protein biomarkers were identified in uterine fluid and exosomes isolated from the uterine fluid using mass spectrometry. Follow-up statistical analysis permitted to develop diagnostic algorithms that combined 2 or 3 proteins using logistic regression models. Out of the best performing biomarkers, we selected 6 and initiated the development of 6 sandwich ELISAs to detect and quantify these proteins. Subsequently, we started a validation phase in a new independent case-control retrospective cohort of 152 patients (76 case; 76 control) and measured the concentration of these 6 proteins in uterine fluid samples using the developed ELISAs. Results Among 106 proteins studied by mass spectrometry in uterine fluid samples from 358 patients, 58 proteins had significant endometrial cancer diagnostic potential. Among those, a 3-protein panel was used to diagnose patients with a negative predictive value (NPV) 97% and Sensitivity 99%. ELISA development phase was initiated with the production of recombinant antigens and monoclonal antibodies that were used as key reagents in our proprietary immunoassays. Once the key reagents were produced, we carried out the optimization of the ELISA protocols to ensure sensitive, specific and reproducible assays. In a new validation phase, a total of 6 proteins were studied in uterine fluids from 152 patients using our developed proprietary ELISAs. The best 3-protein combination achieved a diagnostic performance of NPV 95% and Sensitivity 97%. Conclusion This study validates the use of our developed proprietary immunoassays to diagnose endometrial cancer in uterine fluid samples by measuring a novel panel of 3 protein biomarkers. Based on these results, we are finalizing the development of WomEC, a diagnostic test that has the potential to be implemented in routine clinical laboratories to aid in the diagnosis of endometrial cancer in women presenting with abnormal uterine bleeding.