Genes differentially expressed in medulloblastoma and fetal brain

Serial analysis of gene expression (SAGE) was used to identify genes that m ight be involved in the development or growth of medulloblastoma, a childho od brain tumor. Sequence tags from medulloblastoma (10229) and fetal brain (10692) were determined. The distributions of sequence tags in each populat ion were compared, and for each sequence tag, pairwise chi-square test stat istics were calculated. Northern blot was used to confirm some of the resul ts obtained by SAGE. For 16 tags, the chi-square test statistic was associa ted with a P value < 10(-4). Among those transcripts with a higher expressi on in medulloblastoma were the genes for ZIC1 protein and the OTX2 gene, bo th of which are expressed in the cerebellar germinal layers. The high expre ssion of these two genes strongly supports the hypothesis that medulloblast oma arises from the germinal layer of the cerebellum. This analysis shows t hat SAGE can be used as a rapid differential screening procedure.