Immunohistochemical analysis of atypical ductular reaction in the human liver, with special emphasis on the presence of growth factors and their receptors

Aims/Background: The objective of this study was to characterize the expres sion of transforming growth factor-alpha/epidermal growth factor receptor, hepatocyte growth factor/c-met, transforming growth factor-beta/Type I-II t ransforming growth factor-beta receptors, stem cell factor, urokinase plasm inogen activator, smooth muscle actin, CD34 and alpha-fetoprotein in human liver samples with (sub)massive necrosis of different etiology containing a typical ductular reaction. Methods: Their presence was studied by immunohis tochemistry on paraffin-embedded tissue sections. Results: Transforming gro wth factor-alpha and -beta, hepatocyte growth factor and their receptors we re demonstrated in the ductules; additionally stem cell factor and urokinas e plasminogen activator were also expressed. The atypical ductules were sur rounded by smooth muscle actin-positive activated stellate cells. Conclusio n: These phenotypic similarities confirm that the atypical ductules in the human liver may be equivalent of oval cells in the rat liver, which are reg arded as the progeny of stem cells. That is, the atypical ductular prolifer ation may correspond to a stem cell-fed regenerative process.