The tumour microenvironment in oral squamous cell carcinoma

Abstract

Background The aim of this project was to look at aspects of the tumour micro-environment in oral squamous cell carcinoma (OSCC). Methods Immune-associated gene expression was assessed using focused array technology and real-time polymerase chain reaction. Single and doubled labelled immunohistochemistry and immunofluorescence techniques were used to determine protein expression. Fresh and formalin-fixed paraffin embedded samples of OSCC tissue, lymph nodes containing metastatic OSCC and normal oral mucosa were studied. Results Increased numbers of toll-like receptor (TLR)2 + keratinocytes were seen within the OSCC microenvironment compared with control epithelium. Other cells expressing TLR2 in the tumour microenvironment were large and morphologically consistent with macrophages or dendritic cells. The presence of TLR2 + FoxP3 + regulatory T cells were also found within the OSCC immune cell infiltrate. Gene expression analysis demonstrated that OSCCs and metastatic lymph nodes showed increased expression of genes associated with T cell anergy. Conclusions The results of the present study have shown increased numbers of TLR2 + cells in OSCC which could potentially be modulated to shift the environment towards a Thl environment thus stimulating the pro-inflammatory process. At the same time T cell anergy might contribute to the molecular ability of OSCC to progress and metastasise to secondary lymphoid organs