| 1. |
- Hoebeeck, J, et al.
(författare)
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The von Hippel-Lindau tumor suppressor gene expression level has prognostic value in neuroblastoma
- 2006
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 119:3, s. 624-629
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Tidskriftsartikel (refereegranskat)abstract
- Deletions of the short arm of chromosome 3 are often observed in a specific subset of aggressive neuroblastomas (NBs) with loss of distal 11q and without MYCN amplification. The critical deleted region encompasses the locus of the von Hippel-Lindau gene (VHL, 3p25). Constitutional loss of function mutations in the VHL gene are responsible for the VHL syndrome, a dominantly inherited familial cancer syndrome predisposing to a variety of neoplasms, including pheochromocytoma. Pheochromocytomas are, like NB, derived from neural crest cells, but, unlike NB, consist of more mature chromaffin cells instead of immature neuroblasts. Further arguments for a putative role of VHL in NB are its function as oxygen sensitizer and the reported relation between hypoxia and dedifferentiation of NB cells, leading to a more aggressive phenotype. To test the possible involvement of VHL in NB, we did mRNA expression analysis and sought evidence for VHL gene inactivation. Although no evidence for a classic tumor suppressor role for VHL in NB could be obtained, a strong correlation was observed between reduced levels of VHL mRNA and low patient survival probability (p = 0.013). Furthermore, VHL appears to have predictive power in NTRK1 (TRKA) positive tumor samples with presumed favorable prognosis, which makes it a potentially valuable marker for more accurate risk assessment in this subgroup of patients. The significance of the reduced VHL expression levels in relation to NB tumor biology remains unexplained, as functional analysis demonstrated no clear effect of the reduction in VHL mRNA expression on protein stability of its downstream target hypoxia-inducible factor alpha. (c) 2006 Wiley-Liss, Inc.
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| 2. |
- Van Roy, N, et al.
(författare)
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Translocation-excision-deletion-amplification mechanism leading to nonsyntenic coamplification of MYC and ATBF1
- 2006
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 45:2, s. 107-117
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Tidskriftsartikel (refereegranskat)abstract
- Despite oncogene amplification being a characteristic of many tumor types, the mechanisms leading to amplicon formation have remained largely unresolved. In this study, we used a combinatorial approach of fluorescence in situ hybridization and single-nucleotide polymorphism chip gene copy number analyses to unravel the mechanism leading to nonsyntenic coamplification of MYC and ATBF1 in SJNB-12 cells. To explain our findings, we propose a complex series of events consisting of multiple double-strand breaks, accompanied (or triggered) by the formation of a reciprocal translocation t(8; 16), as well as excisions and deletions near the translocation breakpoints. This study provides evidence for a translocation-excision-deletion-amplification sequence of events rather than a breakage-fusion-bridge model, which has been more frequently proposed to explain proto-oncogene amplification. Furthermore, it illustrates the power of presently available tools for detailed analysis of the complex rearrangements that accompany amplicon formation.
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