RESUMO
BACKGROUND: Preservation of homeostasis status in the skin needs an equilibrium of keratinocyte proliferation, differentiation, necrosis and apoptosis. Disturbance of these regulatory mechanisms may lead to keratinocyte neoplastic and hyperproliferative diseases. Pigment epithelium-derived factor is a glycoprotein that is endogenously produced in different tissues and has a variety of biological effects in different diseases. OBJECTIVE: To evaluate the keratinocyte expression of pigment epithelium-derived factor in normal skin and three epidermal hyperproliferative diseases, namely, psoriasis, verrucae and squamous cell carcinoma. METHODS: This study included skin biopsy samples from 80 participants who were divided into four equal groups; each containing 20 samples. The first group included skin biopsies from normal skin, the second group from psoriatic lesions, the third group from verruca vulgaris and the fourth group from squamous cell carcinoma. All tissue samples were stained with hematoxylin and eosin stain and later immunohistochemically for pigment epithelium-derived factor expression. RESULTS: Scores of pigment epithelium-derived factor expression were lower in squamous cell carcinoma and verruca and psoriasis than normal skin with a significant difference (P = 0.04). In addition, the pattern of pigment epithelium-derived factor expression was mainly cytoplasmic in normal skin with a significant difference with that seen in psoriasis, squamous cell carcinoma and verruca vulgaris (P = 0.001). CONCLUSION: Pigment epithelium-derived factor may play a role in keratinocyte differentiation.