[Oncogene amplification in human neuroblastomas].

N-myc, which has partial sequence homology to the oncogene c-myc, was isolated from human neuroblastoma cell lines. We have surveyed amplification of N-myc, clone 8 and pG21 in human neuroblastoma cell lines, xenografts and in primary tumors and found that amplification frequently occurred in tumors classified as stage III and IV. In situ hybridization studies demonstrated that in neuroblastomas, chromosome aberrations such as HSR (homogeneously staining region) and DMs (double minutes) are cytological manifestations of the amplification of these clones. The N-myc-related gene seems to contribute to cell growth or differentiation of the nerve cell and its amplification with enhanced expression promotes the progression of the tumor with poor prognosis.