Genomic alterations normally associated with medulloblastomas, including MYC amplification and isochromosome 17q, were easily detected. Surprisingly, analysis of only five genomes revealed novel amplicons on chromosome 14q, one of which contained the orthodenticle homologue 2 (OTX2) homeobox gene. DNA copy number analysis showed that OTX2 had undergone genomic amplification in 2 of 11 medulloblastoma cell lines and 8 of 42 primary tumors