Comparative genomic hybridization (CGH) was used to examine gains and losses in 18 meningioma tumors that had been previously analyzed for loss of heterozygosity (LOH) at 22q12. Partial or complete losses were seen by CGH in only 9 of 18 cases on chromosome 22. This compares with 11 of 18 losses of single or more loci by LOH. The discrepancy in these results in probably explained by the increased sensitivity of LOH by using microsatellite markers that are able to detect small deletions, whereas losses on the order of 10-15 megabases are required for confident identification by CGH. There was no consistent pattern of gains or losses by CGH, including those tumors that lacked LOH at 22q12. In one tumor of interest in which CGH and LOH studies failed to demonstrate loss on chromosome 22, CGH identified an area of amplification at 17q22-23.