Proteoglycans in bladder tumors are modified with a distinct oncofetal chondroitin sulfate (ofCS) glycosaminoglycan that is normally restricted to placental trophoblast cells. This ofCS-modification can be detected in bladder tumors by the malarial VAR2CSA protein, which in malaria pathogenesis mediates adherence of parasite-infected erythrocytes within the placenta. In bladder cancer, proteoglycans are constantly shed into the urine, and therefore have the potential to be used for detection of disease. In this study we investigated whether recombinant VAR2CSA (rVAR2) protein could be used to detect ofCS-modified proteoglycans (ofCSPGs) in the urine of bladder cancer patients as an indication of disease presence. We show that ofCSPGs in bladder cancer urine can be immobilized on cationic nitrocellulose membranes and subsequently probed for ofCS content by rVAR2 protein in a custom-made dot-blot assay. Patients with high-grade bladder tumors displayed a marked increase in urinary ofCSPGs as compared to healthy individuals. Urine ofCSPGs decreased significantly after complete tumor resection compared to matched urine collected preoperatively from patients with bladder cancer. Moreover, ofCSPGs in urine correlated with tumor size of bladder cancer patients. These findings demonstrate that rVAR2 can be utilized in a simple biochemical assay to detect cancer-specific ofCS-modifications in the urine of bladder cancer patients, which may be further developed as a noninvasive approach to detect and monitor the disease.

膀胱肿瘤中的蛋白多糖被一种独特的癌胎儿硫酸软骨素（ofCS）糖胺聚糖修饰，这种糖胺聚糖通常仅限于胎盘滋养层细胞。这种 CS 修饰可以在膀胱肿瘤中通过疟疾 VAR2CSA 蛋白检测到，该蛋白在疟疾发病机制中介导胎盘内寄生虫感染的红细胞的粘附。在膀胱癌中，蛋白多糖不断流入尿液中，因此有可能用于疾病检测。在本研究中，我们研究了重组 VAR2CSA (rVAR2) 蛋白是否可用于检测膀胱癌患者尿液中的 CS 修饰蛋白聚糖 (ofCSPG)，作为疾病存在的指示。我们证明膀胱癌尿液中的 ofCSPG 可以固定在阳离子硝酸纤维素膜上，随后在定制的斑点印迹测定中通过 rVAR2 蛋白探测 ofCS 含量。与健康个体相比，患有高级别膀胱肿瘤的患者尿中 ofCSPG 显着增加。与术前从膀胱癌患者收集的匹配尿液相比，完全肿瘤切除后CSPG的尿液显着减少。此外，尿液中的 CSPG 含量与膀胱癌患者的肿瘤大小相关。这些发现表明，rVAR2 可用于简单的生化测定，以检测膀胱癌患者尿液中癌症特异性的 CS 修饰，这可能会进一步开发为检测和监测疾病的非侵入性方法。