Klin Padiatr 2004; 216 - 35
DOI: 10.1055/s-2004-828580

In depth analysis of aberrantly methylated genes detected by genome scanning in medulloblastoma and other malignancies of the CNS

T Lenschen 1, J Mühlisch 1, H Jürgens 1, C Plass 2, D Smiraglia 3, MC Frühwald 1
  • 1Department of Pediatriatic Hematology and Oncology, University Childrens Hospital Münster, Germany
  • 2Divison of Human Cancer Genetics, The Ohio State University, USA
  • 3Department of Cancer Genetics, Roswell Park Cancer Institute, USA

Introduction: Silencing of genes by methylation is an important mechanism to inactivate tumor suppressor genes. Restriction Landmark Genomic Scanning using restriction enzyme combinations with NotI EcoRV or AscI EcoRV allow the scan of up to 4.000 CpG-Islands for aberrant methylation. Thus genes that might play a role in tumor development and metastasis can be identified.

Results: The examination of 3 anaplastic ependymomas, 5 stPNET, 25 medulloblastomas and 7 cell lines by Restriction Landmark Genomic Scannning using NotI-EcoRV revealed 225 methylated CpG Islands. More than 30 methylated in at least 10 different tumors and cell lines .

19 CpG-Islands were cloned employing a library based technique or identified using a PCR based virtual scanning method. For seven the methylation could be confirmed by Southern Blot Analysis. The methylation status of the CpG-Islands of the identified genes is currently examined by COmbined Bisulfit Restriction Analysis and by Bisulfit Sequencing.Methylated genes were located on 17q23, 19p13.3 (2 genes), 19q13.3, 19q12, 2p24.3. The gene products are e.g. part of phosphotyrosine dependentsignalling pathways or part of a swi/snf-like chromatin remodeling complex and thus potential candidates with a role in oncogenesis.

Conclusion: The evaluation of tumors using RLGS and the cloning of new CpG-Islands allowed us to identify further methylated genes. To confirm their possible role in tumor development correlational studies of expression and methylation are in progress.

Supported by Deutsche Krebshilfe 10–2091-Fr 2 and the Karl Bröcker Stiftung