Differential Urinary Proteomics and Absolute Protein Quantification Reveal Biomarkers of Muscle-Invasive and Non-Muscle-Invasive Bladder Cancer

A comparative urinary proteomic analysis using the Total Protein Approach (TPA) revealed distinct protein abundance profiles between patients with muscle-invasive (MIBC) and non-muscle-invasive bladder cancer (NMIBC), suggesting potential diagnostic utility. Notably, several proteins, including periostin (POSTN), immunoglobulin variable regions (IGLV3-21, IGHV3-49, IGHV5-51), and complement regulator (C4BPB), were found at significantly higher concentrations in the urine of MIBC patients. These findings support their value as non-invasive indicators of tumour aggressiveness. The TPA-based urinary protein signature holds promise for improving early risk stratification, detecting biological features associated with invasive disease, and may inform treatment strategies.