AbstractProstate cancer (PCa) exhibits a significant health risk to aging men, in which effective diagnosis of high gleason (Gleason >7) cancers is of critical need. Currently, the main screening tool utilized for detection of prostate cancer is prostate specific antigen (PSA), however, PSA exhibits limited utility in men with benign prostatic hyperplasia (BPH) due to inherent elevated PSA as the result of an enlarged prostate, resulting in increasing unnecessary biopsies. In Mexico, there is currently a higher incidence of aggressive PCa due to the risk within the overall population as well as the need for increased screening tools. Since, there is a critical unmet need to evaluate novel PCa diagnostic test that could serve as a reflex test within the screening paradigm, we evaluated the recently developed test, pSTATEdx, which measures the cleaved portion of Filamin A (FLNA) via IP-MRM mass spectrometry in conjunction with the patients age, to determine the overall risk of aggressive prostate cancer. In the current study, we analyzed a prospective cohort from Mexico City and Guadalajara evaluating 34 BPH and 44 PCa in men exhibiting symptoms with PSA levels between 4-10 ng/mL, who were all referred for 12 core prostate biopsies due to suspicion of prostate cancer. Additionally, we assessed 41 non-diseased men as controls who had PSA below 1.5 ng/mL, who were not assessed further. Comparison of non-diseased controls with BPH/PCa men exhibited an AUC of 0.99, PPV 0.96, NPV 0.89, OR 118, and P value 2 e-20, thus demonstrating that pSTATEdx had significant utility in assessing prostate health independent of PSA. In comparison with previously published data, FLNA mean levels were 24 ng/mL in previously published American study cohort and 55 ng/mL in the Mexican BPH/PCa cohort with a P value of <0.001. Assessment of patient populations revealed that there was superior diagnostic performance of FLNA for patients between PSA 4-7, which represents an increased unmet need for biopsy decision support. Analysis of BPH compared to all PCa exhibited a sensitivity of 0.94 and specificity of 0.53, PPV 0.64, NPV of 0.91, and OR of 16.4. Diagnostic analysis of BPH compared to high gleason PCa exhibited a sensitivity of 1, specificity of 0.21, PPV 0.38, NPV of 1, and OR of inf in this pilot study. This assessment revealed promising insight that aggressive PCa was not missed using pSTATEdx. pSTATEdx demonstrated diagnostic utility in prevention of unnecessary biopsies in the Mexican population as a reflex test to those patients with PSA levels between 4-7 as well as demonstrated that aggressive prostate cancers were not missed with the risk score. Additional studies are planned in the future to expand the utility of pSTATEdx in Latin America.Citation Format: Arturo Rodriguez, Arturo Mendoza, Matthew Rosenburg, José de J. Castaneda, Alejandro A. Melgar, Bernardo Ciseros, Adrian G. Gangemi, Nischal M. Chand, Poornima Tekumalla, Greg Miller, Anjan Thakurta, Diego Banuelos, Juan J. Real, Diego A. Joya, Alejandro Romero, Juan D. Farias, Eduardo Cabeza, Hector H. Remess, Julio J. Delgado, Hector M. Sanchez, Ignacio Barragan, Mabel Rodriguez, Barbara Garcia, David A. Sanchez, Juan Izquierdo, Elizabeth M. Lopez, Juan Hanao, Jeronimo G. Frusch, Niven R. Narain, Michael A. Kiebish. Diagnostic assessment of Filamin A (FLNA) as a serum biomarker for identification of benign prostatic hyperplasia vs aggressive prostate cancer in a prospective Mexican cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3751.