MYCC and MYCN oncogene amplification in medulloblastoma. A fluorescence in situ hybridization study on paraffin sections from the Children's Oncology Group.
BACKGROUND
Brain tumors are the most common solid tumor in childhood, and medulloblastoma is the most common malignant brain tumor in this age group. Cytogenetic abnormalities that have been described in childhood medulloblastoma include loss of 17p, amplification of MYCC (c-myc), amplification of MYCN (N-myc), and isochromosome 17q. Data on these tumors indicate that the frequency of MYCC amplification is 5% to 10%. Fluorescence in situ hybridization is a powerful tool for investigating these features on archival material.


OBJECTIVE
To determine if intratumoral heterogeneity exists for MYCC and MYCN in medulloblastomas and if tumors with amplified MYCC or MYCN exhibit consistent histologic patterns.


METHODS
In this fluorescence in situ hybridization study, we investigated the frequency and prognostic significance of MYCC and MYCN amplification in 77 medulloblastomas derived from the Children's Oncology Group.


RESULTS
MYCC amplification occurred in only 4 (5.2%) of 77 tumors. The 4 patients died of clinically aggressive neoplasms within 7 months of diagnosis. Similarly, 4 of 77 patients' tumors were found to exhibit MYCN amplification, but survival data are incomplete at present, therefore prognostic significance cannot be characterized.


CONCLUSIONS
These data establish the frequency of MYCC amplification in a large cohort of children with medulloblastoma and further suggest that MYCC amplification may be a marker of poor prognosis. Intratumoral heterogeneity was identified for these oncogenes in that 1 patient's tumor exhibited evidence of both MYCN and MYCC amplification, and this patient experienced a shortened survival time.
Aldosari
Naji
N
Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA.
Bigner
Sandra H
SH
Burger
Peter C
PC
Becker
Laurence
L
Kepner
James L
JL
Friedman
Henry S
HS
McLendon
Roger E
RE
D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005784:Gene Amplification; D016259:Genes, myc; D006801:Humans; D017403:In Situ Hybridization; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D008527:Medulloblastoma / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D015996:Survival Rate
D004273:DNA, Neoplasm