Fluorescence in situ hybridization determination of 22q12-q13 deletion in two intracerebral ependymomas

The sole cytogenetic abnormalities encountered in two childhood anaplastic intracerebral ependymomas were an isodicentric chromosome 22 in one case an d an unbalanced chromosome 22 translocation associated with a partial delet ion in the other. Fluorescence in situ hybridization analysis showed that t he common 22q arm loss did not involve the rhabdoid region but included the EWS and NF2 loci. These results, in conjunction with data in the literatur e, suggest that the most frequently recurrent genomic loss in ependymomas d oes not involve the proximal 22q11.2 chromosome region but is localized dis tally to the hSNF5/INI1 locus. A tumor-suppressor gene, independent of the NF2 gene, which seems to be exclusively involved in intramedullary spinal c ord ependymomas, might be implicated in the genesis of these intracranial t umors. (C) 2000 Elsevier Science Inc. All rights reserved.