Infrequent mutation of Waf1/p21 gene, a CDK inhibitor gene, in brain tumors
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1Department of Neurosurgery, Niigata University.
Abstract:
Possible mutations of the Waf1/p21 gene, a cyclin-dependent kinase (CDK) inhibitor gene, were investigated in biopsy specimens of 28 brain tumors using polymerase chain reaction (PCR)-single strand conformation polymorphism and nucleotide sequence analysis. There were 15 astrocytic tumors, six medulloblastomas, five pineal parenchymal tumors, and two neuroblastomas. A mutation was detected in exon 2, which comprises 90% of the cording region including the CDK inhibitory domain, in only two samples. A missense mutation was detected at codon 33 in rare PCR clones from an astrocytic tumor and a silent mutation was detected at codon 35 in a medulloblastoma. Therefore, mutation of the Waf1/ p21 gene is infrequent in these brain tumors. Examination of deoxyribonucleic acid (DNA) from normal subjects and paired DNA of brain tumor patients observed a polymorphism at codon 31, which encodes either Ser (AGC) or Arg (AGA).
Insights
Mutations in the Waf1/p21 gene are infrequent in common brain tumors like astrocytomas and medulloblastomas. Researchers found only two mutations in 28 brain tumor samples, suggesting p21 is rarely altered in these cancers.
Area of Science:
- Molecular Biology
- Oncology
- Genetics
Background:
- The Waf1/p21 gene encodes a cyclin-dependent kinase (CDK) inhibitor, crucial for cell cycle regulation.
- Alterations in cell cycle regulators are common in cancer development.
- The role of Waf1/p21 gene mutations in brain tumors requires further investigation.
Purpose of the Study:
- To investigate the frequency and types of mutations in the Waf1/p21 gene in various human brain tumors.
- To analyze potential correlations between Waf1/p21 gene mutations and specific brain tumor types.
Main Methods:
- Biopsy specimens from 28 brain tumors (15 astrocytic tumors, 6 medulloblastomas, 5 pineal parenchymal tumors, 2 neuroblastomas) were analyzed.
- Polymerase chain reaction (PCR)-single strand conformation polymorphism and nucleotide sequence analysis were employed.
- DNA from normal subjects and paired brain tumor patients was examined for polymorphisms.
Main Results:
- Mutations in the Waf1/p21 gene were detected in only two out of 28 brain tumor samples.
- A missense mutation at codon 33 and a silent mutation at codon 35 were identified in specific tumor types.
- A common polymorphism at codon 31 (Ser/Arg) was observed in DNA from both normal individuals and brain tumor patients.
Conclusions:
- Mutation of the Waf1/p21 gene appears to be infrequent in the investigated spectrum of brain tumors.
- The study highlights the low incidence of Waf1/p21 gene alterations in these specific central nervous system malignancies.
- Further research may explore the functional significance of the identified Waf1/p21 polymorphism in brain tumor development.