Role of inflammation in oral carcinogenesis (Part I): Histological grading of malignancy using a binary system.

The aim of the present study was to assess the suppressant role of the inflammatory infiltrate in oral carcinogenesis through the immunohistochemical expression of CD8 and FOXP3 and to discuss how representative this expression proved, as well as other parameters considered to be of prognostic value. A total of 20 cases of oral epithelial dysplasia and 40 cases of oral squamous cell carcinoma were selected. The criteria suggested by the World Health Organization were used for the histological grading of dysplasia. For carcinoma, a binary method was developed for the present study using parameters such as type of invasion, maturity, presence of epithelial masses and dysmorphism of the masses. Immunohistochemical analysis was performed for assessment of the expression of anti-CD8 and anti-FOXP3 in cases of dysplasia and carcinoma. Although the inflammatory infiltrate was more intense in the majority of carcinomas, it exercised a protective role in the dysplasia cases, as CD8 expression was significantly greater. Although a correlation was found between CD8 and the intensity of the inflammatory infiltrate in the carcinoma cases, CD8 demonstrated >5% expression in only 32.5% of the cases, compared to 80% of the dysplasia cases. Thus, we suggest that the inflammatory infiltrate should not be used as a parameter in routine examinations, as it plays different roles in the various stages of carcinogenesis. The histological grading system for malignancy employed in the present study is indicated for the assessment of oral squamous cell carcinoma.