Genome-wide Matrix-CGH analysis of Hodgkin and Reed-Sternberg cells in Hodgkin’s lymphoma
senior researcher: PD Dr. Stefan Joos in colaboration with: Prof. Dr. P. Möller, Institute for Pathology, University of Ulm; Prof. Dr. H. Stein, Institute for Pathology, Benjamin Franklin Hospital, University Berlin.
Fig.1: Isolation of HRS cells in Hodgkin’s lymphoma by micro-dissection and examples of chromosome 9 copy number gains after CGH analysis. In order to recognize the cells they were stained with an CD30 antibody. Isolation was performed using a thin needle connected to a micromanipulator. After collecting and pooling about 20 HRS cells, the genomic DNA was amplified by universal PCR and used as probe for CGH analysis. Examples show ratio profiles and examples of the hybridization pattern indicating additional copies of the short arm of chromosome 9.
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Hodgkin`s lymphoma represents the most frequent neoplasia of childhood in Europe. Genomic analysis of tumor cells in Hodgkin’s lymphoma (known as Hodgkin and Reed-Sternberg cells or HRS cells) has been very difficult in the past. Major reasons for this are the rarity of these cells within the tumor mass and the high complexity of chromosomal rearrangements. In collaboration with PD Dr. A. Jauch (Human Genetics Department, University of Heidelberg) we further applied mulicolor FISH and could identify subtle chromosomal rearrangements in HRS cell. Furthermore, we isolated pools of HRS cells, amplified the genomic DNA by universal PCR and performed CGH (Fig. 1). In this way, we identified clusters of chromosomal gains, in particular on the short arm of chromosomes 2 and 9. Interesting candidate genes within these regions, as e.g. the c-REL oncogene as well as the JAK2 gene are currently analyzed for their protein expression and activation by tyrosine phosphorylation. Furthermore, we currently focus on the analysis of HRS cells by Matrix-CGH in order to determine chromosomal aberrations with higher resolution as compared to conventional CGH.
selected publications in this field:
- Primary mediastinal (thymic) B-cell lymphoma is characterized by gains of chromosomal material including 9p and amplification of the REL gene.
- Genomic imbalances including amplification of the tyrosine kinase gene JAK2 in CD30+ Hodgkin cells.
- Classical Hodgkin lymphoma is characterized by recurrent copy number gains of the short arm of chromosome 2.
- Hodgkin's lymphoma cell lines are characterized by frequent aberrations on chromosomes 2p and 9p including REL and JAK2.
Funding
This project is funded by the 'Deutsche Forschungsgemeinschadt (DFG)'. (click icon to view www.dfg.de)
