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Evolution of VHL tumourigenesis in nerve root tissue.
Haemangioblastomas are the key central nervous system manifestation of von Hippel-Lindau (VHL) disease, which is caused by germline mutation of the VHL gene. We have recently shown that 'tumour-free' spinal cord from patients with VHL disease contains microscopic, poorly differentiated cellular aggregates in nerve root tissue, which we descriptively designated 'mesenchymal tumourlets'. Here we have investigated spinal cord tissue affected by multiple tumours. We show that a small subset of mesenchymal tumourlets extends beyond the nerve root to form proliferative VHL-deficient mesenchyme and frank haemangioblastoma. We thus demonstrate that tumourlets present potential, but true precursor material for haemangioblastoma. We further show that intraradicular tumourlets consist of scattered VHL-deficient cells with activation of HIF-2alpha and HIF-dependent target proteins including CAIX and VEGF, and are associated with an extensive angiogenic response. In contrast, activation of HIF-1alpha was only observed in the later stages of tumour progression. In addition, ultrastructural examination reveals gradual transition from poorly differentiated VHL-deficient cells into vacuolated cells with a 'stromal' cell phenotype. The evolution of frank haemangioblastoma seems to involve multiple steps from a large pool of precursor lesions.
|Title:||Evolution of VHL tumourigenesis in nerve root tissue.|
|Keywords:||Antigens, CD31, Basic Helix-Loop-Helix Transcription Factors, Cerebellar Neoplasms, Hemangioblastoma, Humans, Hypoxia-Inducible Factor 1, alpha Subunit, Immunohistochemistry, In Situ Hybridization, Microscopy, Electron, Neoplasm Proteins, Neovascularization, Pathologic, Spinal Cord Neoplasms, Spinal Nerve Roots, Stem Cells, Up-Regulation, Vascular Endothelial Growth Factor A, Von Hippel-Lindau Tumor Suppressor Protein, von Hippel-Lindau Disease|
|UCL classification:||UCL > School of Life and Medical Sciences
UCL > School of Life and Medical Sciences > Faculty of Medical Sciences
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