Clinicopathological implications of tumour-associated macrophages and vascularization in sinonasal melanoma

This study investigated tumour-associated macrophages (TAMs) and their effects on tumour vascularization in sinonasal melanoma (SNM). Data on 45 patients with SNM undergoing surgery were reviewed retrospectively. Tumour sections were analysed immunohistochemically for TAMs, microvessels, lymph vessels, and vasculogenic mimicry in both intra- and peritumoural areas. The density of intratumoural TAMs was associated with tumour thickness and with overall survival in SNM stages I and II but there were no correlations between micro- or lymph vessel density and TAM infiltration. Greater TAM infiltration was observed in tumour tissues with vasculogenic mimicry although this was not statistically significant. These data suggest that high intratumoural TAM infiltration is associated with tumour aggressiveness and a poor prognosis for SNM, and that activation of macrophages can be polarized by different micro-environments. TAMs could be potential prognostic indicators for patients with SNM.