Circulating levels of soluble urokinase plasminogen activator receptor (suPAR) to predict outcome after resection of biliary tract cancer.

Abstract

572 Background: Surgical resection is the only curatively intended therapy for patients with biliary tract cancer (BTC), but 5-year survival rates after tumor resection have remained below 30%, corroborating the need for better preoperative stratification tools to identify the ideal surgical candidates. The soluble urokinase plasminogen activator receptor (suPAR) represents a mediator of inflammation and has recently been associated with cancer. In this study, we evaluated a potential role of suPAR as a novel biomarker in patients undergoing resection of BTC. Methods: Tumor expression of uPAR, the membrane bound source of suPAR, was analyzed by IHC in 108 BTC samples. Serum levels of suPAR were analyzed by ELISA in a training and validation cohort comprising a total of 117 BTC patients and 76 healthy controls. Results: A high tumoral uPAR expression was associated with an adverse outcome after BTC resection. In line, circulating levels of suPAR were significantly elevated in BTC patients compared to healthy controls and patients with primary sclerosing cholangitis (PSC). Using a small training set, we established an optimal prognostic suPAR cut-off value of 3.72ng/ml for BTC patients. Importantly, preoperative suPAR serum levels above this cut-off value were associated with significantly impaired overall survival in both the training and validation cohort. Multivariate Cox-regression analysis including clinicopathological parameters such as the tumor stage, markers of systemic inflammation or organ dysfunction and established tumor markers revealed suPAR as an independent prognostic marker following BTC resection. Finally, high preoperative suPAR levels were indicative for acute kidney injury after tumor resection. Conclusions: Circulating suPAR represents a previously unrecognized biomarker in patients with resectable BTC, which might be useful to preoperatively identify the ideal candidates for tumor resection.