Related Experiment Videos
Amplification of the c-myc proto-oncogene in human chondrosarcoma
J S Castresana1, C Barrios, L Gómez
1Department of Tumor Pathology, Karolinska Hospital, Stockholm, Sweden.
Abstract:
The genomic organization of four oncogenes, i.e., c-myc, c-myb, c-Ha-ras, and c-fms, was investigated in fresh surgical specimens from 10 patients with cartilaginous tumors. Among nine chondrosarcomas, six were primary lesions and three local recurrences. The remaining case was a chondroblastoma. Amplification of the c-myc proto-oncogene was the sole abnormality detected in this series, occurring in two chondrosarcomas (four- and eight-fold). No other genetic alteration such as oncogene rearrangement was found. Nor was there any amplification of the other oncogenes studied. Both c-myc-amplified tumors were primary lesions and histologically classified as grade II; according to flow DNA cytometry, one was diploid and the other aneuploid. In our limited series, there was no overall relationship between c-myc amplification, on the one hand, and histologic subtype, malignancy grade, surgical stage, or ploidy level, on the other. Our study shows that amplification of the c-myc oncogene, presumed to be involved in the development of malignancy, is encountered in occasional human chondrosarcomas, however, without any relationship to other well-known features of this tumor entity. The clinical significance of this gene amplification remains to be established.
Insights
c-myc proto-oncogene amplification was found in some human chondrosarcomas. This genetic abnormality occurred without relation to tumor grade, stage, or ploidy, and its clinical significance requires further study.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Cartilaginous tumors, including chondrosarcomas, are characterized by genetic alterations.
- Proto-oncogenes play a role in tumor development and progression.
Purpose of the Study:
- To investigate the genomic organization of four key oncogenes (c-myc, c-myb, c-Ha-ras, c-fms) in cartilaginous tumors.
- To determine the frequency and potential correlations of oncogene abnormalities, particularly c-myc amplification, in chondrosarcomas.
Main Methods:
- Genomic DNA was extracted from fresh surgical specimens of 10 patients with cartilaginous tumors (9 chondrosarcomas, 1 chondroblastoma).
- Southern blot analysis was used to detect amplification and rearrangement of c-myc, c-myb, c-Ha-ras, and c-fms oncogenes.
- Histological grading and flow DNA cytometry were performed.
Main Results:
- c-myc proto-oncogene amplification was the only genetic abnormality detected, occurring in two out of nine chondrosarcomas (four- and eight-fold amplification).
- No oncogene rearrangement or amplification of c-myb, c-Ha-ras, or c-fms was observed.
- The two c-myc-amplified tumors were primary, grade II chondrosarcomas; one was diploid and the other aneuploid by DNA cytometry.
Conclusions:
- Amplification of the c-myc oncogene occurs in a subset of human chondrosarcomas.
- In this series, c-myc amplification showed no correlation with histological subtype, malignancy grade, surgical stage, or ploidy.
- The clinical significance of c-myc gene amplification in chondrosarcomas remains to be elucidated.