S100A4 and urinary bladder cancer: Using an MS-based discovery approach combined with a Western blotting (WB)/ELISA-based validation approach, they reported five differentially expressed proteins including S100A4, S100A8, S100A9, carbonic anhydrase I, and annexin V. Furthermore, two biomarkers, S100A8 and S100A9, demonstrated high accuracy (ROC, 0.946) in differentiating 81% of bladder cancer (both low-grade and high-grade) cases from healthy controls, exhibiting the highest levels of sensitivity and specificity.