N-myc and c-myc oncogenes amplification in medulloblastomas. Evidence of particularly aggressive behavior of a tumor with c-myc amplification.
N-myc and c-myc amplification was investigated in 27 medulloblastomas. DNA was extracted from 19 formalin fixed and paraffin embedded tumors and from fresh frozen tumor tissue in 8 other cases. The results showed no evidence of amplification of N-myc oncogene and only 1 case had a 27 fold amplification of c-myc. Cytogenetically, this neoplasm presented numerous double minute chromosomes (DMs). Moreover, it had an unusual rapidly aggressive course with massive cerebrospinal fluid dissemination unresponsive to intrathecal chemotherapy. Our results indicate a low incidence of N-myc and c-myc gene amplification in medulloblastomas, suggesting that the oncogenic mechanism in these neoplasms is not closely related to DNA gene amplification. C-myc amplification, although not frequently observed, may however provide a growth advantage for medulloblastoma cells in vivo, favoring their rapid dissemination. Medulloblastomas with c-myc activation may represent a subgroup of tumors with a more aggressive behavior.
Badiali
M
M
Department of Pediatrics, University of Bologna, Italy.
Pession
A
A
Basso
G
G
Andreini
L
L
Rigobello
L
L
Galassi
E
E
Giangaspero
F
F
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004273:DNA, Neoplasm / Q000032:analysis*; D005784:Gene Amplification / Q000235:genetics*; D016259:Genes, myc; D006801:Humans; D007223:Infant; D008527:Medulloblastoma / Q000235:genetics*; D012189:Retrospective Studies
D004273:DNA, Neoplasm