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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A132
Pilocytic astrocytomas are the most prevalent tumor type in children and
considered being benign glioma. In this study, we used comparative genomic
hybridization (CGH) to identify genetic alterations unique to this tumor type.
We analyzed 18 pilocytic astroctomas by means of comparative genomic
hybridization. Ten cases of pilocytic astrocytoma were located in the
cerebellum and eight supratentorial. All tumors showed gains and losses of
DNA by CGH, and in many cases multiple changes were observed. The most
commonly observed genetic aberration, occurring in ten tumors, was deletions
on chromosome 13q, suggesting that this chromosome contain loci involved in
the development of pilocytic astrocytoma. Moreover, we have observed the
large number of random chromosomal alterations in this tumor. The prevalent
changes for cerebellar pilocytic astrocytomas were: -4q, -6q, -13q, -18q,
+17p, +17q-ter, +19p, +19q whereas for supratentorial location most common
changes were: -1q-ter, -2q, -13q, -19q, -20q-ter. One case of optic glioma
was characterized by following changes: -6q, -14q, -17p, -19q, -21q and -22q.
We concluded that although pilocytic astrocytomas are benign tumors,
multiple chromosomal gain and losses were observed Specific combination of
multiple chromosomal losses characterizes pilocytic astrocytomas may help
to differentiate them unequivocally from other types of tumors of the central
nervous system.
ANALYSIS OF GENETIC ALTERATIONS BY COMPARATIVE GENOMIC HYBRIDIZATION
IN PILOCYTIC ASTROCYRTOMAS
Szymas J 1, Petersen I 2, Wolf G 2 , Nowak S 3
1) Department of Pathology, K. Marcinkowski University of Medical Sciences,
Poznan, Poland. 2) Institute of Pathology, University-Hospital Charite,
Berlin, Germany, 3) Department of Neurosurgery, K. Marcinkowski University
of Medical Sciences, Poznan, Poland.