Morphometric analysis of the tumor associated tissue eosinophilia in the oral squamous cell carcinoma using different staining techniques.

In a previous study, we found tumor-associated tissue eosinophilia (TATE) to be a favourable prognostic indicator for oral squamous cell carcinomas. Special techniques such as autofluorescence or immunohistochemistry are reported to be sometimes necessary to detect the presence of intact and degranulating eosinophils within the tumors. The aim of this study was to compare the number of eosinophils identified routinely with hematoxylin and eosin stain and by immunohistochemistry in oral squamous cell carcinomas with TATE. Thirty specimens of oral squamous cell carcinoma of the tongue, floor of the mouth, retromolar area and inferior gingiva with TNM stages II and III were used for histopathological analysis. Three-micrometer sections were stained with hematoxylin and eosin and immunohistochemically with monoclonal anti-human granulocyte-associated antigen using a standard streptavidin-biotin-peroxidase complex technique. The number of eosinophils/mm2 in the invasive front of the tumors was automatically quantified in a x400 field using an image computer analyser. Univariate statistical analysis was carried out using Student's t test. The computer-assisted morphometric results showed that there was no statistically significant difference (p>0.05) in the number of eosinophils/mm2 identified by hematoxylin and eosin or immunostaining technique in oral squamous cell carcinomas with TATE. This result suggests that hematoxilyn and eosin routine stain is a useful technique for measuring eosinophils in squamous cell carcinoma with eosinophilic tumor infiltration.