M2-polarized tumour-associated macrophages in stroma correlate with poor prognosis and Epstein-Barr viral infection in nasopharyngeal carcinoma.

OBJECTIVES: To assess the relationships between CD163 expression, localization of CD163+ macrophages, clinicopathological features and prognosis of NPC.

METHODS: A total of 110 cases of NPC specimens and 80 cases of nasopharyngitis specimens were analysed for CD163 expression by immunohistochemistry and EBERs expression in situ hybridization.

RESULTS: CD163 + macrophages in the tumour stroma were positively correlated with the tumour and nodal stage. Higher expression of Epstein-Barr virus-encoded RNAs (EBERs) in the nuclei of tumour cells was associated with higher density of CD163 + macrophages in the tumour stroma. More importantly, greater infiltration of CD163 + macrophages in the tumour stroma was associated with poor overall survival (OS) and poor progression-free survival (PFS). Multivariate analysis revealed that the density of CD163+  macrophages in the tumour stroma may be an independent risk factor for NPC prognosis.

CONCLUSIONS: Increased infiltration of CD163+  macrophages in the tumour stroma correlates with worse outcomes and with Epstein-Barr virus (EBV) infection status of tumour cells in nasopharyngeal carcinoma (NPC).