Immunohistochemical characterization of human γ-irradiated skin

An immunohistochemical analysis was carried out in order to characterize the phenotypic modifications induced by γ-rays in human skin and to study the expression of some growth factors and growth factor receptors. Following radiotherapy for breast carcinoma, dermal fibroblasts of mammary skin are located superficially near the dermo-epidermal junction. They exhibit either vimentin-positive/smooth muscle cells (SMC) α-actin-negative quiescent phenotype or vimentin-positive/SMC α-actin-positive 'reactive' myofibroblastic phenotype but no desmin intermediate filaments. Using two polyclonal antibodies against Transforming Growth Factor β (TGFβ), we observed a specific intranuclear staining in fibroblasts and epidermal cells. Epidermal Growth Factor-Receptors (EGFR) were detected as membrane-associated in all the epidermal cell layers of irradiated skin and this pattern appears strongly associated with previous irradiation. These data suggest that complex cellular interactions are involved between epidermal and dermal cells and with extracellular matrix components, mediated by various cytokines, including TGFβ and EGF-like factors