CYTOGENETIC ANALYSIS OF 39 PEDIATRIC CENTRAL-NERVOUS-SYSTEM TUMORS

Consistent cytogenetic abnormalities have been described in many pediatric solid tumors, including Ewing's sarcoma, Wilm's tumor, and neuroblastoma. Similar analysis of pediatric central nervous system (CNS) tumors has been hampered by technical problems. We report chromosome results from 39 pediatric CNS tumors. Abnormalities of chromosome 17 were noted in 3 of 11 primitive neuroectodermal tumors (including i(17q) in 2 tumors), confirming data observed by other investigators. Cells from 2 of 11 primitive neuroectodermal tumors (PNET) exhibited loss or structural abnormalities involving chromosome 11. Loss or distal deletion of chromosomes 7q was noted in cells from two PNETs. Because other investigators have shown loss of heterozygosity on 17p in about one-third of PNET, we propose that chromosome regions 7q and 11 are areas worthy of further study in pediatric PNET. Numerical abnormalities were noted in 6 of 21 astrocytomas. Hyperdiploidy was demonstrated in 1 of 4 pilocytic astrocytomas and pseudopolyploidy was demonstrated in 4 of 13 anaplastic astrocytomas. Structural chromosome abnormalities (translocations, deletions) were noted in 4 of 13 anaplastic astrocytomas. Complex structural anomalies were observed in one craniopharyngioma. A rhabdoid tumor of the brain exhibited multiple complex structural rearrangements but did not exhibit the monosomy 22 observed in some rhabdoid tumors. Hypodiploidy and loss of chromosome 22 were noted in a clinically aggressive meningioma, corroborating observations by other investigators.