Application of urinary proteomics in early diagnosis of bladder urothelial carcinoma

Abstract

To investigate the difference in urinary proteome between patients with bladder urothelial carcinoma (BUC) and healthy volunteers and to provide a basis for the early diagnosis of BUC. The urine samples from BUC patients and healthy volunteers (controls) were treated by 25% ethanol precipitation and two-dimensional gel electrophoresis (2-DE), and the obtained urinary proteins were subjected to Coomassie brilliant blue staining and analysis by PDQuest 8.0 (2-DE image analysis software); the differentially expressed proteins were sequenced by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry and identified using the Swiss-Prot database; the differential expression of these proteins was verified by western blot. High-resolution and high-reproducibility 2-DE images were obtained from the urine samples of BUC patients and controls, with 789 ± 18 and 762 ± 14 protein spots, respectively. Compared with the control group, the BUC grouP had significantly decreased expression of 6 protein spots and significantly increased expression of 11 protein spots. The mass spectrometry revealed five proteins with increased expression in the BUC group, including fibrinogen, lactate dehydrogenase B, apolipoprotein A1, clusterin, and haptoglobin, and the results were confirmed by western blot. There is significant difference in urinary proteome between BUC patients and healthy volunteers; the identification of differentially expressed proteins in urine lays the foundation for identifying potential molecular markers in early diagnosis of BUC.