Detection of early-stage extrahepatic cholangiocarcinoma in patients with biliary strictures by soluble B7-H4 in the bile.

Increasing evidence has demonstrated that serum soluble B7-H4 (sB7-H4) is a useful tumour marker for cancer diagnosis and prognosis evaluation. Whether sB7-H4 is expressed in the bile of cholangiocarcinoma (CC) and is related to the progression of CC need to be explored. Bile sB7-H4 was obtained through endoscopic retrograde cholangiopancreatography (ERCP) from 213 patients with biliary strictures and detected was detected by a B7-H4 ELISA kit. Diagnostic value was compared among bile sB7-H4, CA19-9, CA12-5, CEA and ERCP-based cytological/tissue examination. Additionally, the correlations between the bile sB7-H4 concentration and the clinical characteristics of early-stage cholangiocarcinoma (ESCC) were studied. The bile sB7-H4 levels of patients with ESCC were significantly higher than in patients with benign biliary strictures (BBS) (P<0.001). The receiver operating characteristic (ROC) curves of CA19-9, CA12-5 and CEA were 0.713, 0.554 and 0.451, respectively, were significantly lower than the ROC curves of bile sB7-H4 (0.837), the sensitivity of ERCP-based cytological/tissue examination was 57.5% and 68.4%, which was lower than that of bile sB7-H4 (81.7%) at cut-off value. A high level of bile sB7-H4 in patients with ESCC was found to be correlated with vascular invasion (P<0.001), lymph node metastasis (P<0.001) and TNM stage (P=0.018), respectively. The overall survival rate (OS) of ESCC patients in the high sB7-H4 group was significantly lower than the OS of patients in the low sB7-H4 group (P=0.009). Bile sB7-H4 could serve as a valuable biomarker for patients with ESCC and high levels of bile sB7-H4 correlate with poor clinical outcomes.