Aim: Eotaxin is a powerful and selective eosinophil chemoattractant. The purpose of this study was to compare the expression of eotaxin in oral squamous cell carcinomas with and without tumour associated tissue eosinophilia (TATE). The mechanisms that control the recruitment of eosinophils to these tumours are not clearly established.
Methods: A total of 60 patients with oral squamous cell carcinomas (OSCC) with TNM stages II and III, located in the tongue, oral floor, retromolar area and inferior gingiva were divided in two groups: 1--OSCC with intense eosinophilic inflammatory infiltrate and 2--OSCC with absent/low eosinophilic inflammatory infiltrate. The eotaxin expression was analyzed by immunohistochemistry using standard streptavidin-biotin-peroxidase complex technique with monoclonal (mouse anti-human eotaxin) and polyclonal (rabbit anti-human eotaxin) antibodies.
Results: The eotaxin expression was identified in normal oral mucosa as well as in both OSCC groups including malignant epithelial cells, eosinophils, neutrophils, plasma cells and fibroblasts. The eosinophils showed intense immunopositivity for eotaxin.
Conclusion: These results suggest that the eotaxin expressed in oral squamous cell carcinomas, mainly derived from eosinophils, is probably involved in the mechanisms of eosinophils chemotaxis to the tumour and in the maintenance of TATE in these malignant tumours.