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In vitro Organoid Culture of Primary Mouse Colon Tumors
Published on: May 17, 2013
Oncogenes and suppressor genes: their involvement in colon cancer
1Division of Digestive Diseases, New York Hospital--Cornell Medical Center, NY 10021.
Abstract:
Abnormalities in oncogenes, which are broadly classified into viral and cellular oncogenes, and suppressor genes appear critical for the development of colon cancer. Cellular oncogenes contribute to malignant transformation when they become activated by point mutation, translocation, amplification, or loss of regulator sequences. The properties of the oncoproteins, the proteins encoded by oncogenes which are essential for carcinogenesis, are unclear. Suppressor genes normally suppress the tumorigenic phenotype by keeping the growth of cells in check; it is their inactivation that contributes to malignant transformation. Development of colon cancer appears to take place by stepwise accumulation of multiple genetic alterations during the progression from normal colon to adenoma and carcinoma. Activation of ras, an early event in this sequence, is found in 50% of colon cancers; overexpression of c-myc is found in approximately 80%. Inactivation of suppressor genes, which occurs during later stages, is noted in greater than 70% of tumors. A current model of colonic tumorigenesis is presented.
Insights
Genetic alterations in oncogenes and suppressor genes drive colon cancer development. Stepwise accumulation of these changes, including ras activation and c-myc overexpression, leads to tumor progression.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Colon cancer development involves critical abnormalities in oncogenes and suppressor genes.
- Cellular oncogenes drive malignant transformation via mutations, translocations, or amplification.
- Suppressor genes normally inhibit cell growth; their inactivation promotes tumorigenesis.
Discussion:
- Oncogene activation, such as ras, is an early event in colon cancer, present in 50% of cases.
- Overexpression of c-myc occurs in approximately 80% of colon cancers.
- Inactivation of tumor suppressor genes is a later event, found in over 70% of tumors.
Key Insights:
- Colon cancer arises from a stepwise accumulation of genetic alterations.
- Specific oncogenes (ras, c-myc) and suppressor gene inactivation are key molecular events.
- Understanding these genetic changes provides a model for colonic tumorigenesis.
Outlook:
- Further research into oncoprotein properties is needed.
- Targeting oncogene activation and suppressor gene inactivation may offer therapeutic strategies.
- Elucidating the complete genetic pathway is crucial for effective colon cancer prevention and treatment.
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