Abstracts from the 8th meeting of the experimental neuro-oncology group, W�rzburg, Germany
✍ Scribed by F. Sinks, Lucius
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 60 KB
- Volume
- 33
- Category
- Article
- ISSN
- 0098-1532
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✦ Synopsis
Isochromosomes are monocentric or dicentric chromosomes with homologous arms that are attached in a reverse configuration as mirror images. With an incidence of 3-4%, the i(17q) represents the most frequent isochromosome in human cancer. It is found in a variety of tumors, particularly in blast crisis of chronic myeloid leukemia (CML-BC), acute myeloid leukemia (AML), non-Hodgkin's lymphoma (NHL) and in medulloblastoma (MB) and indicates a poor prognosis. To determine the breakpoints on the molecular genetic level, we have analysed seven MB with an i(17q) and two MB with a pure del(17p) applying fluorescence in situ hybridization (FISH) with yeast artificial chromosome (YAC)-, P1artificial chromosome (PAC)-clones and cosmids from a well characterized contig covering more than 6 Mb of genomic DNA. We identified four different breakpoint cluster regions. One is located close to or within the centromere of chromosome 17 and a second in the Charcot-Marie-Tooth (CMT1A) region at 17(p11.2). A third breakpoint was found telomeric to the CMT1A region. The fourth, most common breakpoint was bordered by two adjacent cosmid clones (clones D14149 and M0140) within the Smith-Magenis syndrome (SMS) region. These results indicate that the low copy number repeat gene clusters which are present in the CMT-as well as in the SMS-region may be one of the factors for the increased instability that may trigger the formation of an i(17q).