GROWTH-FACTOR PROFILES OF HUMAN GLIOMAS - DO NONTUMOR CELLS CONTRIBUTE TO TUMOR-GROWTH IN GLIOMA

Background: Growth factors play a role in proliferation and motility o f malignant glial cells, through autocrine and paracrine mechanisms. A lso, proliferation of non-tumour cells, e.g., endothelial cells, is li kely to be controlled by growth factors. Several growth factors with t heir appropriate receptors can be involved, but studies on tissue spec imens evaluating this in glioma are rare. Materials and Methods: We ev aluated the potential role of Transforming growth factor-alpha (TGF-al pha) and Epidermal growth factor receptor (EGF-R), the Platelet-derive d growth factor A-and B-chain (PDGF-A and PDGF-B) and its receptors (P DGFR alpha and PDGFR beta), and basic fibroblast growth factor (bFGF) in gliomas by analysing 86 of these tumours on the single cell level f or the presence of immunoreactive growth factors and receptors. In a f ew cases double-staining experiments were done to directly visualize c o-expression of factor and receptor. Results: Multiple growth factors and their receptors are present in astrocytic tumours; the higher the grade, the more growth factors and the more positive cells are found. Oligodendroglial rumours and pilocytic astrocytomas showed little expr ession. Autocrine and paracrine mechanisms were frequently possible in the astrocytic tumours, often more than one loop could be involved. I nterestingly, it was also frequently possible that non-tumour cells pr oduced a growth factor for which the tumour cells expressed the recept or. Conclusions: Multiple growth factors appear to be involved in astr ocytic tumours, with frequent autocrine and paracrine loops. Expressio n of these molecules seems to increase with increasing grade. The resu lts argue for a contribution of non-tumour cells to the growth of a tu mour.