Value of bile soluble B7-H3 for the diagnosis of malignant biliary strictures: Results of a retrospective study

Aims: Increasing evidence has demonstrated that serum soluble B7-H3(sB7-H3) is a useful tumor marker for cancer diagnosis and prognostic evaluations. Whether sB7-H3 expressed in the bile is related to the progression of malignant biliary strictures must be clarified. Methods: Bile sB7-H3 was obtained via endoscopic retrograde cholangiopancreatography (ERCP) from 323 patients suspected to have malignant biliary strictures and was detected using a B7-H3 ELISA kit. Diagnostic value was compared among bile sB7-H3, CA19-9, CA12-5, and CEA and ERCP-based cytological/tissue examination. Additionally, the correlations between the bile sB7-H3 concentration and the clinical characteristics of malignant biliary strictures were studied. Results: The bile sB7-H3 levels of patients with malignant biliary strictures were significantly higher than those in patients with benign biliary strictures (P < 0.001). The AUC values of the receiver operating characteristic (ROC) curves for CA19-9, CA12-5 and CEA were 0.764, 0.475 and 0.399, respectively, which were significantly lower than that of sB7-H3 (0.878); the sensitivities of ERCP-based cytological and tissue examinations were 55.7% and 66.4%, respectively, which were far lower than that of bile sB7-H3(81.2%). A high level of sB7-H3 in patients with malignant biliary strictures was found to be correlated with vascular invasion(P < 0.001), lymph node metastasis(P < 0.001), distant metastasis (P < 0.001) and tumor-node-metastasis (TNM) stage (P = 0.01). The overall survival rate of the patients in the high sB7-H3 group was significantly lower than that of the patients in the low sB7-H3 group(P = 0.014). Conclusions: Bile sB7-H3 could serve as a valuable biomarker for patients with malignant biliary strictures and high levels of bile sB7-H3 were associated with poor clinical outcomes.