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

BACKGROUND: 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). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.