[Loss of heterozygosity on chromosomes 1 and 19 in cases of primary brain tumour].
BACKGROUND
Histological classification of brain tumours, including gliomas, can be difficult, and genetic investigations are increasingly significant in their classification and the development of treatment strategies. Oligodendrogliomas often show a loss of heterozygocity for the short arm of chromosome 1 and the long arm of chromosome 19 (LOH 1p/19q), changes that influence both treatment and prognosis. Our aim was to evaluate the incidence of combined loss of heterozygocity 1p and 19q in various glioma groups.


METHODS
A total of 10 oligodendrogliomas (5 WHO grade II and 5 grade III), 10 mixed gliomas (5 WHO grade II and 5 grade III), 10 astrocytomas (5 WHO grade II and 5 grade III) and 11 glioblastomas (WHO grade IV) were investigated. Normal hippocampal tissue was used as a control. Formalin-fixed paraffin-embedded tissue was scrutinized with fluorescent in situ hybridization (FISH) with fluorochrome-conjugated double-strand DNA probes for 1p and 19q, respectively.


RESULTS
A significiant loss of 1p/19q was found in the oligodendrogliomas; the astrocytomas showed a selective loss of 19q; the glioblastomas showed a selective loss of 1p but also polyploidy.


CONCLUSIONS
This investigation confirms other reports on increased LOH 1p/19q in oligodendrogliomas. Various studies have demonstrated a large variation in the incidence of LOH 1p/19q. This might be due to inter- and intraobserver variability in the histological classification. Another factor might be variations in techniques. Most studies have been made on imprints. A standard for the method, including the number of cells counted, the cutoff limit and the statistical variation, is necessary for future studies and clinical use.
Born
Pernille Wolder
PW
Neuropatologisk Laboratorium, H:S Rigshospitalet, DK-2100 København Ø.
Broholm
Helle
H
Laursen
Henning
H
D001254:Astrocytoma / Q000235:genetics / Q000473:pathology / Q000628:therapy; D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics*; D005909:Glioblastoma / Q000235:genetics / Q000473:pathology / Q000628:therapy; D005910:Glioma / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D006801:Humans; D017403:In Situ Hybridization; D019656:Loss of Heterozygosity; D009367:Neoplasm Staging; D009837:Oligodendroglioma / Q000235:genetics / Q000473:pathology / Q000628:therapy