PROGNOSTIC-SIGNIFICANCE OF CHROMOSOME 17P DELETIONS IN CHILDHOOD PRIMITIVE NEUROECTODERMAL TUMORS (MEDULLOBLASTOMAS) OF THE CENTRAL-NERVOUS-SYSTEM

Deletions in the short arm of chromosome 17 (17p) are the most common genetic abnormality in primitive neuroectodermal tumors of the posteri or fossa/medulloblastoma (PNET/Mb). The biological consequences of the se deletions are not known for children with PNET/Mb; however, the pre sence of a tumor suppressor gene located in 17p, distinct from p53, ha s been implicated in tumorigenesis. Two recent studies suggest that 17 p deletions in PNET/Mb are associated with a poor prognosis, To addres s this question, we identified deletions of chromosome 17p by cytogene tic and/or molecular biology methods in tumor biopsy samples from 56 p atients with PNET/Mb. Associations between clinical characteristics or survival outcomes and 17p status were examined by multivariate analys is, Forty-one percent of PNET/Mb cases had a deletion of 17p, No signi ficant association was found between 17p deletion and shorter survival duration or higher metastatic stage. Multivariate analysis did not fi nd independent prognostic significance for 17p deletions after account ing for the effects of significant clinical variables, A larger study of the prognostic value of 17p deletion should be considered; however, clinical use of factor to distinguish high-risk from standard-risk PN ET/Mb populations is not warranted at this time.