Precise data on the incidence of transforming ras oncogenes in pediatric tumors and the correlations with the histopathological properties of the tumors are very limited. Additionally the presence of ras activation in medulloblastomas has not been investigated so far. Using a combination of techniques including in vitro gene amplification by polymerase chain reaction (PCR) and detection of single base mutations by sequence-specific oligonucleotides we studied N-ras activation (mutations at codon 12, 13, and 61) in 32 medulloblastomas. DNA was isolated from 20 μm sections of formalin-fixed paraffin-embedded tissue. Mutations were found in 3 out of 32 examined medulloblastomas. In all cases only mutations of codon 61 were found: two of three mutations were C to A mutations at position 1 of the condon 61 (leading to a substitution of a glutamine residue for a lysine) and one was A to T mutation at position 3 in the same codon (glutamine-histidine). Our results indicate 10% incidence N-ras mutation in medulloblastoma, higher than in other CNS tumors studied so far. The main advantages of the procedure described are its greatly improved sensitivity, the increased speed with which tumor samples can be analyzed, and the possibility of using paraffin-embedded sections to analyze various rare tumors in retrospect.
|Number of pages||6|
|Journal||Medical and Pediatric Oncology|
|Publication status||Published - 1991|
ASJC Scopus subject areas
- Cancer Research
- Pediatrics, Perinatology, and Child Health