EXTENSIVE GENOMIC ABNORMALITIES IN CHILDHOOD MEDULLOBLASTOMA BY COMPARATIVE GENOMIC HYBRIDIZATION

We analyzed 27 samples of primary medulloblastoma, using comparative g enomic hybridization and a novel statistical approach to evaluate chro mosomal regions for significant gain or loss of genomic DNA, An array of nonrandom changes was found in most samples. Two discrete regions o f high-level DNA amplification of chromosome bands 5p15.3 and 11q22.3 were observed in 3 of 27 tumors, Nonrandom genomic Losses were most fr equent in regions on chromosomes 10q (41% of samples), 11 (41%), 16q ( 37%), 17p (37%), and 8p (33%), Regions of DNA gain most often involved chromosomes 17q (48%) and 7 (44%). These findings suggest a greater d egree of genomic imbalance in medulloblastoma than has been recognized previously and highlight chromosomal loci likely to contain oncogenes or tumor suppressor genes that may contribute to the molecular pathog enesis of this tumor.