Human medulloblastomas lack point mutations and homozygous deletions of the hSNF5/INI1 tumour suppressor gene

Medulloblastomas (MBs) are malignant primitive neuroectodermal tumours (PNETs) of the cerebellum occurring predominantly in childhood. The association of monosomy of chromosome 22 with MB is controversial.,typical teratoid/rhabdoid tumours (AT/RTs) of the brain share clinical and histological features With MBS arid supratentorial PNETs (sPNETs). In particular. AT/RTs can be misdiagnosed as NIBS and sPNETs because AT/RTs frequently contain areas of primitive neuroepithelial cells similar to PNETs. Recently. mutations of the tumour suppresser gene hSNF5/IN11, located on 22q11.23. have been described in AT/RTs. MBs and sPNETs. with conflicting data on the prevalence of hSNF5/IN11 mutations in the latter entities. Therefore. we screened MBs for point mutations and homozygous deletions of the hsNF5/IN11 tumour suppressor gene. In 90 MBS, no mutations of the hSNF5/IN11 gene were identified. Thus. our study virtually rules out hSNF5/IN11 as a tumour suppressor gene involved in the pathogenesis of medulloblastoma.