MYCN AMPLIFICATION IN PEDIATRIC BRAIN-TUMORS - DETECTION BY DIFFERENTIAL POLYMERASE CHAIN-REACTION

MYCN amplification is frequently observed in tumors such as neuroblast omas, but is uncommon in pediatric brain tumors, which represent the m ost common solid tumors of childhood. MYCN amplification is rarely des cribed in gliomas and some primitive neuroectodermal tumors (PNETs) of the central nervous system. Oncogene amplification has traditionally been determined quantitatively by Southern blotting, a time consuming technique often requiring more DNA than is available from small brain tumor biopsies. We applied the novel technique of differential polymer ase chain reaction (PCR) to a small series of 8 pediatric brain tumors to assess the presence of MYCN amplification. The tumors included 4 c erebellar PNETs, 1 cerebral PNET, 1 malignant glioma, 1 subependymal g iant cell tumor, and 1 ganglioglioma. Differential PCR showed MYCN amp lification in 1 cerebellar PNET and 1 malignant glioma, with amplifica tion 20-fold and 80-fold, respectively, above diploid controls. Our re sults confirm that differential PCR is a useful technique to assess on cogene amplification in pediatric brain tumors.