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Analysis of the p16INK4 and TP53 tumor suppressor genes in bone sarcoma pediatric patients
A Patiño-García1, L Sierrasesúmaga
1Laboratory of Pediatrics, University of Navarra, Pamplona, Spain.
Abstract:
Recent data suggest that deletion of p16INK4 and mutation of TP53 are among the most common genetic events in the development of human cancer, since the codified proteins act as brakes of the abnormal cell cycle. As the molecular events leading to the development of pediatric bone sarcomas remain unclear, we analyzed 75 osteosarcoma and Ewing sarcoma samples from 43 pediatric patients to search for alterations at the TP53 or p16INK4 tumor suppressor genes. By means of PCR-DGGE (polymerase chain reaction and denaturing gradient gel electrophoresis) we detected TP53 point mutations in 18.6% of the tumor samples, but no constitutional mutations. In the analysis of p16INK4, 7% of the samples harbored deletions of the gene but no point mutations were detected by SSCP (single strand conformation polymorphism) analysis, just the polymorphism Ala-->Thr at codon 148. These data support the hypothesis that TP53 alterations may play a role in the development of pediatric bone tumors and that the primary mechanism of inactivation of p16INK4 seems to be homozygous deletion rather than point mutation.
Insights
TP53 gene mutations were found in 18.6% of pediatric bone tumors. The p16INK4 gene was deleted in 7% of samples, suggesting these genetic alterations contribute to tumor development.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- TP53 and p16INK4 are critical tumor suppressor genes, acting as cell cycle regulators.
- Their inactivation is common in human cancers, but their role in pediatric bone sarcomas is not well understood.
Purpose of the Study:
- To investigate genetic alterations in the TP53 and p16INK4 tumor suppressor genes in pediatric bone sarcomas.
- To clarify the molecular mechanisms underlying the development of osteosarcoma and Ewing sarcoma.
Main Methods:
- Analysis of 75 osteosarcoma and Ewing sarcoma samples from 43 pediatric patients.
- Utilized Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) to detect TP53 mutations.
- Employed Single Strand Conformation Polymorphism (SSCP) analysis for p16INK4 alterations.
Main Results:
- TP53 point mutations were identified in 18.6% of tumor samples; no constitutional mutations were found.
- Homozygous deletions of the p16INK4 gene were detected in 7% of samples.
- No p16INK4 point mutations were observed, except for a known polymorphism at codon 148.
Conclusions:
- TP53 alterations likely contribute to the development of pediatric bone tumors.
- The primary mechanism for p16INK4 inactivation in these tumors appears to be homozygous deletion, not point mutation.