Significance of apolipoprotein A1 as biomarker for early diagnosis and classification of bladder urothelial carcinoma

Objective To investigate the significance of apolipoprotein (Apo)-Al in unne as a biomarker for early diagnosis and classification of bladder urothelial carcinoma (BUC).Methods Urine samples were divided into four groups:normal control group,benign bladder disease group,low-grade malignant BUC group,and high-grade malignant BUC group.Apo-A1,which showed significantly different expression among the four groups,was selected according to the two-dimensional electrophoresis (2-DE) images of the four groups,and enzyme-linked immunosorbent assay (ELISA) was used to quantify Apo-A1 in the four groups.A receiver operating characteristic (ROC) curve was generated,and the optimal operating points on the ROC curve were found to determine the critical concentrations of Apo-A1 for early diagnosis of BUC and differentiation of low-grade and high-grade malignant BUC.The results were verified clinically,and the specificity and sensitivity were calculated.Results The 2-DE images showed that that the level of Apo-A1 increased from the normal control grouPto high-grade malignant BUC group.The ELISA showed that there was no significant difference in Apo-A1 level between the normal control grouPand benign bladder disease group,but the Apo-A1 level was significantly higher in the BUC groups than in the normal control grouPand benign bladder disease grouP (P＜0.01); the high-grade BUC grouPhad a significantly higher Apo-A1 level than the low-grade BUC grouP (P＜0.01).The BUC patients and those without BUC could be differentiated with an ApoA1 concentration of 18.22 ng/ml,while the low-grade and high-grade malignant BUC could be differentiated with an Apo-A1 concentration of 29.86 ng/ml.When used as a biomarker,Apo-A1 had a sensitivity of 91.6％(98/107) and a specificity of 85.7％ (42/49) for diagnosis of BUC and had a sensitivity of 83.7％ (41/49) and a specificity of 89.7％ (52/58) for BUC classification.Conclusion Apo-A1 may be a biomarker for early diagnosis and classification of BUC and shows promise for clinical application. Key words: Apolipoprotein A1;  Bladder urothelial carcinoma;  Early diagnosis;  Biomarker