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Onco-suppressor genes in human cancer
G Della Porta1, P Radice, M A Pierotti
1Division of Experimental Oncology A, Istituto Nazionale Tumori, Milan, Italy.
Tumori
|August 31, 1989
Summary
Oncogenes drive cancer through gain-of-function mutations, while onco-suppressor genes, like the RB gene, normally prevent tumors. Loss of both onco-suppressor gene alleles leads to cancer, as seen in retinoblastoma.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- Cancer arises from genetic alterations in cellular genes controlling growth and differentiation.
- Oncogenes, activated by gain-of-function mutations, promote uncontrolled cell proliferation.
- Somatic cell hybrid experiments suggest tumor suppressor genes counteract oncogenic effects.
Purpose of the Study:
- To elucidate the molecular mechanisms of multistep carcinogenesis.
- To differentiate between oncogenes and tumor suppressor genes in cancer development.
- To investigate the role of the retinoblastoma (RB) gene in tumor suppression.
Main Methods:
- Analysis of altered cellular genes (oncogenes) in tumor cells.
- Somatic cell hybridization experiments to study gene dominance and suppression.
- Molecular analysis, cloning, and sequencing of the RB gene.
Main Results:
- Activated oncogenes act as dominant gain-of-function mutations.
- Tumor suppressor genes, when inactivated, act as recessive loss-of-function mutations.
- The RB gene product regulates cell growth and can be inactivated by viral oncoproteins.
Conclusions:
- Multistep carcinogenesis involves both oncogene activation and tumor suppressor gene inactivation.
- Tumor suppressor genes are crucial for normal cell growth regulation.
- Viral oncoproteins can subvert cellular machinery by inactivating tumor suppressor proteins like RB.