Malignant peripheral nerve sheath tumour arising within neurofibroma. An immunohistochemical analysis in the comparison between benign and malignant components

Aims-To compare the expression of immunohistochemical variables between ben ign and malignant components of malignant peripheral nerve sheath tumour (M PNST) arising within neurofibroma. Methods-Eight cases of MPNST arising within a neurofibroma, associated with neurofibromatosis type 1 (NF1), were studied. The areas of MPNST and neuro fibroma were compared immunohistochemically with regard to the expression o f proliferative activity (MIB-1), growth factors, p53, bcl-2, neural cell a dhesion molecule (N-CAM), and CD34. Results-The expression of transforming growth factor beta1 (TGF-beta1), TGF -beta receptor type II, hepatocyte growth factor alpha (HGF-alpha), c-met, p53, and N-CAM was higher in the areas of MPNST than in the neurofibromatou s areas in four, five, five, eight, five, and three of the eight cases, res pectively. CD34 expression was lower in the areas of MPNST than in the neur ofibroma areas in three of the eight cases. Conclusions-On the basis of these findings, TGF-beta1, HGF-alpha, and p53 m ight be involved in the malignant transformation of neurofibroma, to MPNST.