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RESEARCH PRODUCT

Pediatric High-Grade Astrocytomas Show Chromosomal Imbalances Distinct from Adult Cases

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We studied 23 pediatric high-grade astrocytomas by comparative genomic hybridization. Chromosomal imbalances were found in 10 of 10 anaplastic astrocytomas and 11 of 13 glioblastomas and consisted of +1q (43%), +3q (26%), +1p, +2q, +5q (22%), −22q (34%), −6q, −10q (30%), −9q, −11q, −13q, −16q, and −17p (22%). Anaplastic astrocytomas frequently showed +5q (40%), +1q (30%), −22q (50%), −6q, −9q (40%), and −12q (30%); glioblastomas +1q (54%), +3q (38%), +2q, +17q (23%), −6q, −8q, −10q, −13q, and −17p (31%). Minimal common regions mapped to +1q21-41, +3q27-qter, +2q31-32, +5q14-22, −22q12-qter, −10q23-25, −6q25-qter, −9q34.2, −11q14−22, −16q22-qter, and −17p. High-level gains were located on 1q (7 cases), 2q, 7q (4 cases), 3q (3 cases), 9, 17q (2 cases), 4q, 8q, 18, and 20q (1 case). A significantly shorter survival was found for anaplastic astrocytomas showing +1q (P 25% (P < 0.001) and glioblastomas (P < 0.05). Compared with adult cases, +1p, +2q, and +21q as well as −6q, −11q, and −16q were more frequent in pediatric malignant astrocytomas. Among the latter +5q, −6q, −9q, −12q, and −22q were characteristic for pediatric anaplastic astrocytomas and +1q, +3q, +16p, −8q, and −17p for pediatric glioblastomas. Our results show that chromosomal aberrations differ between pediatric anaplastic astrocytomas and glioblastomas as well as between pediatric and adult high-grade astrocytomas, supporting the notion of a different genetic pathway. Furthermore, gains of chromosomal material on 1q might be correlated with a worse prognosis in pediatric anaplastic astrocytomas.