Tumour-infiltrating inflammatory and immune cells in patients with extrahepatic cholangiocarcinoma.

<bold>Background: </bold>Inflammation and immune characteristics of the tumour microenvironment have therapeutic significance. The aim of this study was to investigate the clinical impact on disease progression in human extrahepatic cholangiocarcinoma (ECC).<bold>Methods: </bold>A total of 114 consecutive ECC patients with curative resection between 2000 and 2014 were enrolled. Tumour infiltrating CD66b+ neutrophils (TANs; tumour associated neutrophils), CD163+ M2 macrophages (TAMs; tumour associated macrophages), CD8+ T cells, and FOXP3+ regulatory T cells (Tregs) were assayed by immunohistochemistry, and their relationships with patient clinicopathological characteristics and prognosis were evaluated.<bold>Results: </bold>Tumour associated neutrophils were inversely correlated with CD8+ T cells (P=0.0001) and positively correlated with Tregs (P=0.001). High TANs (P=0.01), low CD8+ T cells (P=0.02), and high Tregs (P=0.04) were significantly associated with poor overall survival (OS). A high-risk signature, derived from integration of intratumoural inflammatory and immune cells, was significantly associated with poor recurrence-free survival (P=0.01) and OS (P=0.0008). A high-risk signature was correlated with postoperative distant metastases. Furthermore, a high-risk signature was related to the resistance to gemcitabine-based chemotherapy used after recurrence.<bold>Conclusions: </bold>Our data showed that tumour infiltrating inflammatory and immune cells may play a pivotal role in ECC progression and a high-risk signature predicted poor prognosis in ECC patients. [ABSTRACT FROM AUTHOR]