Expression of platelet-derived growth factor transcripts in medulloblastomas and ependymomas.
We used Northern blot analysis to measure the expression of mRNA for platelet-derived growth factor subunit A (PDGF-A), PDGF-B and the PDGF-alpha receptor (PDGFR-alpha) and PDGF-beta receptor (PDGFR-beta) in ependymomas and medulloblastomas. We analyzed tissue from 5 patients for each tumor type, looking specifically for components of an autocrine or paracrine system in these tumors. PDGF-A was expressed in all tumors, PDGFR-alpha, which binds all 3 PDGF isoforms, was only found in ependymomas. Thus only ependymomas appeared to have a potential for using PDGFR-alpha autocrine loops. PDGF-B was expressed only in ependymomas, although the PDGFR-beta was expressed in both medulloblastomas and ependymomas. Again, therefore, only ependymomas appear to have a potential autocrine loop with PDGFR-beta. These data suggest that ependymomas have the biochemical prerequisites for autocrine and/or paracrine loops using PDGFR-alpha or PDGFR-beta systems. In this they resemble other glial tumors such as anaplastic astrocytomas and glioblastomas. Medulloblastomas do not appear to have the ligand and/or receptor for either the PDGFR-alpha or PDGFR-beta autocrine loop.
Black
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Neurosurgical Laboratories, Brigham and Women's Hospital Children's Hospital, Boston, Mass., USA.
Carroll
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Glowacka
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D015152:Blotting, Northern; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology; D004806:Ependymoma / Q000235:genetics* / Q000473:pathology; D015870:Gene Expression; D006801:Humans; D008527:Medulloblastoma / Q000235:genetics* / Q000473:pathology; D010982:Platelet-Derived Growth Factor / Q000235:genetics*
D010982:Platelet-Derived Growth Factor