Presence of defensin in epithelial Langerhans cells adjacent to oral carcinomas and precancerous lesions.

We aimed to immunohistochemically study the localization of defensin (HNPs), a family of peptides with antimicrobial and cytotoxic activity, in oral tumor tissue. Therefore, tissue sections were embedded in paraffin, and defensin was immunostained by the streptavidin-biotin coupled peroxidase method. Langerhans cells were confirmed by indirect immunostaining with anti-S-100 protein polyclonal antibody. Melanocytes were stained with Fontana-Masson's stain. Neutrophils and intimal cells were stained by anti-defensin antibody. Langerhans cells in normal epithelium or dysplasic epithelium adjacent to squamous cell carcinoma and precancerous lesion were also stained. Defensins (HNPs) are nonspecific peptides that occur in neutrophils and protect against bacteria, fungi, and tumor cells. Since defensins are also found in epithelial Langerhans cells adjacent to tumor tissue, these peptides most likely have a role in tumor immunity.