Expression of insulin-like growth factor-1 receptor in conventional cutaneous squamous cell carcinoma with different histological grades of differentiation.

BACKGROUND: Insulin-like growth factor-1 receptor (IGF-1R) is a key regulator of cell transformation and controls the expression of genes that governs cell cycling and cell survival. The aim of this pilot study was to gain insight into the expression pattern of IGF-1R in conventional cutaneous squamous cell carcinoma (CSCC) using immunohistochemical analysis. MATERIALS AND METHODS: Five cases of normal human paraffin-embedded skin sections, 4 cases of actinic keratosis, and 28 cases of paraffin-embedded sections of different histological subtypes of CSCC were selected for immunohistochemical analysis. RESULTS: In normal skin, IGF-1R expression was detected in the epidermal basal cell layer. In actinic keratosis, IGF-1R was expressed in the lower part of the epidermis. IGF-1R was detected in the cell surface membrane of well-differentiated CSCC. In moderately differentiated CSCC, IGF-1R was expressed predominantly in the cytoplasm. Interestingly, IGF-1R was expressed in the nuclei of tumor cells of poorly differentiated CSCC. CONCLUSIONS: The strong and differential expression of IGF-1R in different histological degrees of CSCC indicates a possible role for IGF-insulin receptor in the carcinogenesis and differentiation of this disease and identifies IGF-1R as an interesting target for prevention and treatment of CSCC that deserves further investigation.