Increase in placental glutathione S‐transferase in human oral epithelial dysplastic lesions and squamous cell carcinomas

This study investigated the immunohistochemical expression of human placental glutathione S-transferase (GST-pi) in the epithelium of oral premalignant and malignant lesions. Epithelial lining of normal oral mucosa, hyperplastic lesions and oral epithelium exhibiting mild dysplasia showed weak to moderate GST-pi staining. Moderate epithelial dysplasia revealed an increased antibody content while severe dysplasia, carcinoma-in-situ (CIS) and squamous cell carcinoma (SCC) demonstrated markedly increased antibody binding. The GST-pi staining was evident mainly in the cytoplasm. Severe dysplasia, CIS and SCC were also characterized by areas of cells with intensive nuclear GST-pi staining. These findings support the hypothesis that GST-pi plays a role in human oral carcinogenesis and may be used as a tumor marker for human oral premalignant and malignant lesions.