Association of near-diploid DNA content and N-myc amplification in neuroblastomas.
Seventeen neuroblastomas at different clinical stages were analysed for their N-myc copy number and flow cytometrically determined DNA content. Aneuploidy was found in 11 patients (65 per cent), whereas the remaining were near-diploid. N-myc amplification was found significantly (P less than 0.05) confined to near-diploid tumors (3 out of 6 cases). This finding indicates a very selective mechanism of oncogene amplification which is independent of gross chromosomal imbalance and limited to specific loci in the human genome. Association of near-diploidy and age at diagnosis older than 24 months was also demonstrated (P less than 0.05). Thus, flow cytometric analysis of DNA content together with N-myc gene dosage allowed us to distinguish two different subsets of neuroblastoma tumors: the first one aneuploid, with single-copy N-myc, usually observed in patients younger than 24 months with localized or IV-S clinical stages; the second one near-diploid, with frequent N-myc amplification, usually observed in patients older than 24 months with advanced clinical stages.
Dominici
C
C
Department of Pediatrics, University La Sapienza, Rome, Italy.
Negroni
A
A
Romeo
A
A
Castello
M A
MA
Clerico
A
A
Scopinaro
M
M
Mauro
F
F
Raschellà
G
G
D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D004273:DNA, Neoplasm / Q000032:analysis*; D005260:Female; D005434:Flow Cytometry; D005784:Gene Amplification; D006801:Humans; D007223:Infant; D008297:Male; D009367:Neoplasm Staging; D009447:Neuroblastoma / Q000235:genetics*; D009857:Oncogenes
D004273:DNA, Neoplasm