Tumour-associated tissue eosinophilia as a prognostic factor in oral squamous cell carcinomas

Aims: Tumour-associated tissue eosinophilia has been described in many sites, including head and neck. The mechanism of eosinophil recruitment and its role in tumours has not yet been defined, and its presence has been related to a favourable as well as unfavourable prognosis. The aim of this study was to evaluate the influence of tumour-associated tissue eosinophilia on the prognosis of 125 oral squamous cell carcinoma patients. Methods and results: The number of eosinophils was obtained by morphometric analysis and ranged from 0 to 392 per mm(2). Tumour-associated tissue eosinophilia was classified according to intensity as mild, moderate, or intense and correlated statistically to the intensity of the mononuclear inflammatory infiltrate as well as to the location of the eosinophilic inflammatory infiltrate. The multivariate analysis demonstrated that intense tumour-associated tissue eosinophilia is an independent favourable prognostic factor for oral squamous cell carcinomas. Conclusions: These findings suggest an anti-tumoral role of eosinophils not as yet well understood that should be better investigated.