TROP2 Correlates with Microvessel Density and Poor Prognosis in Hilar Cholangiocarcinoma

Trophoblast cell surface antigen 2 (TROP2) was found to be associated with tumor progression and poor prognosis in a variety of epithelial carcinomas. The aim of the study was to investigate TROP2 expression and its prognostic impact in hilar cholangiocarcinoma. Immunohistochemistry and quantitative real-time PCR were used to determine TROP2 expression in surgical specimens from 70 hilar cholangiocarcinoma patients receiving radical resection. The relationship between TROP2 expression and microvessel density was investigated and standard statistical analysis was used to evaluate TROP2 prognosis significance in hilar cholangiocarcinoma. High TROP2 expression by immunohistochemistry was found in 43 (61.4 %) of the 70 tumor specimens. Quantitative real-time PCR confirmed that TROP2 level in tumor was significantly higher than in non-tumoral biliary tissues (P = 0.001). Significant correlations were found between TROP2 expression and histological differentiation (P = 0.016) and tumor T stage (P = 0.031) in hilar cholangiocarcinoma. TROP2 expression correlated with microvessel density in hilar cholangiocarcinoma (P = 0.026). High TROP2 expression patients had a significantly poorer overall survival rate than those with low TROP2 expression (30 vs. 68.5 %, P = 0.001), and multivariate Cox regression analysis indicated TROP2 as an independent prognostic factor for hilar cholangiocarcinoma (P = 0.004). TROP2 expression correlates with microvessel density significantly and is an independent prognostic factor in human hilar cholangiocarcinoma.