[Tumor cytogenetics and prognosis in neuroblastoma]

In 40 children with neuroblastoma of different clinical stages the tumorkaryotype was determined at onset (n = 30) or at relapse (n = 10) of disease after short-term culture of tumor tissues or bone marrow aspirates. None of the 10 stage I, II, and IVs tumors revealed a chromosome 1p aberration, in contrast to stage III and IV tumors where this abnormality was encountered in 25 (=83%) of 30 patients. Amplification of the proto-oncogene N-myc in the tumor-DNA could not be detected in stage I, II and IVs, was however present in 53% of stage III and IV tumors. Cytogenetic phenomena of gene amplification such as Double minutes (DMs) and Homogeneously Staining Regions (HSRs) correlated with N-myc amplification. About 50% of stage III and IV tumors had chromosome numbers in the neardiploid range whereas prognostically favourable tumors were characterized by hyperploid chromosomal numbers mainly in the triploid range. Life-table analysis according to Kaplan-Meier showed a probability of surviving in about 80% of patients with a normal morphology of chromosome 1 in their tumor cells, compared to about 60% in the absence of N-myc oncogene amplification and of about 50%, if aneuploidy is detected. Thus, we think, the presence or absence of chromosome 1p aberration in the tumorkaryotype is the most sensitive discriminator for outcome in children with neuroblastoma.