Abstract In search of more accurate, non-invasive biomarkers of bladder cancer (BC), a comprehensive aptamer-based screen of urine proteins was conducted using urine samples from a BC cohort, followed by systems biology analyses. Following an initial 1317-plex screen, an extended 11,000 plex aptamer-based proteomic screen is in progress. Based on the initial screen, 30 urine proteins were next ELISA validated in an independent cohort of 68 subjects, and the results are shown in Table 1. Of 21 urine proteins that discriminated BC from urology clinic controls (UC), urine D-dimer displayed the highest ROC AUC value (0.96) and sensitivity (95%) (Table 1). Furthermore, 9 urine proteins significantly discriminated more advanced BC (T1-T4) from earlier stages (Ta-Tis), with IL-8 and MMP-12 being the best performers. Urine MMP12 exhibited the highest specificity of 80% at fixed sensitivity for identifying advanced BC. Systems biology analysis implicated molecular functions related to extracellular matrix, collagen, integrin, heparin and transmembrane tyrosine kinase signaling in BC susceptibility, with HNF4A and NFKB1 emerging as key molecular regulators. STEM analysis of the dysregulated pathways implicated a functional role for the immune system, complement and interleukins in BC disease progression. Urine C2, D-dimer, and Elastase were additionally ELISA validated in a second BC cohort of Chinese ethnicity. Thus, comprehensive proteomics and independent ELISA validation have uncovered novel urine biomarkers for initial BC diagnosis and subsequent disease progression, that warrant further head to head comparison with current diagnostic tests. Citation Format: Chandra Mohan, Kamala Vanarsa, Jessica Castillo, Long Wang, Yair Lotan. 11,000-plex aptamer based proteomics of bladder cancer urine for the discovery of novel disease biomarkers [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 3762.