CD155, an immunoglobulin-like adhesion molecule, plays an important role in carcinoma such as cells migration, proliferation, metastasis, and tumor immune. The upregulation of CD155 has been found in several human malignancies, but its expression in cholangiocarcinoma (CCA) still remains unclear. The aim of this study is to investigate CD155 expression and its correlations with clinicopathologic data, angiogenesis, and prognosis in the patients with CCA.

CD155 expression was investigated in 20 paired CCA tissues and corresponding paracancerous tissues by Western blotting and quantitative real-time polymerase chain reaction assays at protein and mRNA levels. Besides, this study evaluated the correlation between the tumor CD155 expression and the level of both vascular endothelial growth factor and intratumoral microvessel density by immunohistochemistry in 90 cases of CCA. Moreover, the clinical and prognostic significance of CD155 in CCA was assessed by immunohistochemistry.

The protein and mRNA levels of CD155 were higher in CCA tumor tissues compared with corresponding paracancerous tissues (P<0.05). Immunohistochemical staining showed that CD155 was located in the cytoplasm of carcinoma cells and overexpressed in 61.2% (55/90) CCA tissues. Obviously, CD155 expression level was significantly correlated with tumor histological grade (P=0.002), lymph node metastasis (P<0.001), and tumor-node-metastasis (P=0.03). Additionally, Spearman rank correlation test demonstrated that CD155 expression was positively associated with vascular endothelial growth factor (r=0.481, P<0.001) and microvessel density (r=0.442, P<0.001) in CCA tissues. More importantly, CCA patients with high CD155 expression had a markedly shorter overall survival (P<0.001) and disease-free survival (P<0.001) after surgical resection, and multivariate analysis showed that high CD155 expression was an independent poor prognostic predictor of overall survival and disease-free survival (P<0.001).

Our results revealed that upregulated CD155 correlated with aggressive clinicopathologic characteristics, angiogenesis, and poor prognosis in CCA and may be a promising prognostic biomarker for the CCA patients.