Reduction to homozygosity and gene amplification in central nervous system primitive neuroectodermal tumors of childhood.

The loss of genetic material from specific chromosomal locations has been identified for a number of pediatric tumors. This loss has been taken as evidence for the importance of tumor suppressor genes at these loci in the genesis of these tumors. One of these pediatric tumors, the primitive neuroectodermal tumor of the central nervous system, has not been well studied. In this report, an analysis of primitive neuroectodermal tumors for allelic deletions on chromosomes 1p, 7q, 10, 11p, 13q, and 17p has been performed. One of ten tumors was found to have increased copies of c-myc. Three different patients were found to reduce to homozygosity at one of three different locations. Significantly, however, three of nine informative patients showed a reduction to homozygosity on chromosome 17p. Thus, primitive neuroectodermal tumor is one of a growing number of tumor types in which deletions in the short arm of chromosome 17 might be important in oncogenesis.