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Analysis of SAS gene and CDK4 and MDM2 proteins in low-grade osteosarcoma
P Ragazzini1, G Gamberi, M S Benassi
1Laboratory of Oncologic Research, Rizzoli Orthopedic Institute, Bologna, Italy.
Abstract:
The region q13-15 of chromosome 12 contains SAS, CDK4, and MDM2 genes that are rearranged or amplified in a variety of human sarcomas. This study evaluated SAS gene amplification, and MDM2 and CDK4 protein expression in 20 tumor samples of central low-grade osteosarcoma (16 primary, 3 recurrences, 1 lung metastasis). SAS amplification was analyzed by quantitative polymerase chain reaction (PCR), while from the same paraffin-embedded samples, MDM2 and CDK4 protein expression was evaluated by immunohistochemistry. MDM2 and CDK4 proteins were found strongly expressed in 35% and 65%, respectively, of the samples. SAS was found amplified in 15% of the samples. These findings indicate that these genes may be involved in tumorigenesis and progression of low-grade osteosarcoma.
Insights
Gene alterations in chromosome 12, including SAS, CDK4, and MDM2, are implicated in low-grade osteosarcoma. This study found SAS amplification and MDM2/CDK4 protein expression in tumor samples, suggesting their role in osteosarcoma development.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- The 12q13-15 chromosomal region harbors SAS, CDK4, and MDM2 genes.
- These genes are frequently altered in various human sarcomas.
Purpose of the Study:
- To evaluate SAS gene amplification and MDM2/CDK4 protein expression in central low-grade osteosarcoma.
- To investigate the potential role of these genetic alterations in osteosarcoma tumorigenesis and progression.
Main Methods:
- Analysis of 20 central low-grade osteosarcoma samples (16 primary, 3 recurrent, 1 lung metastasis).
- Quantitative polymerase chain reaction (PCR) for SAS gene amplification.
- Immunohistochemistry for MDM2 and CDK4 protein expression on paraffin-embedded tissues.
Main Results:
- MDM2 protein overexpression observed in 35% of samples.
- CDK4 protein overexpression observed in 65% of samples.
- SAS gene amplification detected in 15% of samples.
Conclusions:
- MDM2 and CDK4 protein overexpression and SAS amplification are present in a subset of low-grade osteosarcomas.
- These genetic and protein alterations may contribute to the development and progression of low-grade osteosarcoma.