Growth factor profiles of human gliomas. Do non-tumour cells contribute to tumour growth in glioma?
BACKGROUND
Growth factors play a role in proliferation and motility of malignant glial cells, through autocrine and paracrine mechanisms. Also, proliferation of non-tumour cells, e.g., endothelial cells, is likely to be controlled by growth factors. Several growth factors with their appropriate receptors can be involved, but studies on tissue specimens evaluating this in glioma are rare.


METHODS
We evaluated the potential role of Transforming growth factor-alpha (TGF-alpha) and Epidermal growth factor receptor (EGF-R), the Platelet-derived growth factor A- and B-chain (PDGF-A and PDGF-B) and its receptors (PDGFR alpha and PDGFR beta, and basic fibroblast growth factor (bFGF) in gliomas by analysing 86 of these tumours on the single cell level for the presence of immunoreactive growth factors and receptors. In a few cases double-staining experiments were done to directly visualize co-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 tumours and pilocytic astrocytomas showed little expression. Autocrine and paracrine mechanisms were frequently possible in the astrocytic tumours, often more than one loop could be involved. Interestingly, it was also frequently possible that non-tumour cells produced a growth factor for which the tumour cells expressed the receptor.


CONCLUSIONS
Multiple growth factors appear to be involved in astrocytic tumours, with frequent autocrine and paracrine loops. Expression of these molecules seems to increase with increasing grade. The results argue for a contribution of non-tumour cells to the growth of a tumour.
van der Valk
P
P
Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
Lindeman
J
J
Kamphorst
W
W
D001254:Astrocytoma / Q000378:metabolism; D019898:Autocrine Communication; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D002455:Cell Division / Q000502:physiology; D005909:Glioblastoma / Q000378:metabolism; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006133:Growth Substances / Q000378:metabolism*; D006801:Humans; D009837:Oligodendroglioma / Q000378:metabolism; D019899:Paracrine Communication
D006133:Growth Substances