Oncogenes

Definition

Oncogenes are mutated forms of normal genes (proto-oncogenes) that have the potential to cause cancer when they are activated. These genes typically play roles in cell growth, division, and differentiation, and when altered, they can lead to uncontrolled cell proliferation and tumor development.

5 Must Know Facts For Your Next Test

1. Oncogenes can be activated by various mechanisms, including point mutations, gene amplification, or chromosomal translocations.
2. The overexpression or hyperactivity of oncogenes leads to increased signaling for cell proliferation and survival, which can contribute to tumor growth.
3. Some common oncogenes include RAS, MYC, and HER2, which are often targeted in cancer therapies.
4. Cancer treatments such as targeted therapies aim to inhibit the activity of specific oncogenes to slow down or stop tumor progression.
5. Oncogenes differ from tumor suppressor genes in that they promote cell division and survival, while tumor suppressor genes normally inhibit these processes.

Review Questions

• How do oncogenes differ from proto-oncogenes, and what role do they play in cancer development?
  • Oncogenes are mutated versions of proto-oncogenes, which are normal genes that help regulate cell growth and division. When proto-oncogenes undergo mutations or become overactive, they transform into oncogenes that drive uncontrolled cell proliferation. This unregulated growth can lead to the formation of tumors, highlighting the critical role oncogenes play in the pathogenesis of cancer.
• Discuss the mechanisms through which oncogenes can be activated and their implications for cancer treatment.
  • Oncogenes can be activated through various mechanisms including point mutations that alter protein function, gene amplification resulting in overproduction of proteins, and chromosomal translocations that create fusion genes. These activated oncogenes promote excessive cell growth and survival, complicating cancer treatment strategies. Understanding these mechanisms is crucial for developing targeted therapies that can specifically inhibit oncogenic activity and improve patient outcomes.
• Evaluate the impact of oncogene research on the development of targeted therapies in oncology.
  • Research on oncogenes has significantly impacted the field of oncology by leading to the development of targeted therapies designed to inhibit specific oncogenic pathways. Drugs such as trastuzumab (Herceptin) target HER2-positive cancers by blocking the signals that promote tumor growth. By understanding the molecular mechanisms underlying oncogene activation, scientists can create more effective treatments tailored to individual patients' genetic profiles, ultimately enhancing therapeutic efficacy and reducing side effects associated with traditional chemotherapy.

Related terms

proto-oncogenes: Normal genes that, when mutated or expressed at high levels, can become oncogenes and contribute to cancer development.

tumor suppressor genes: Genes that normally help prevent uncontrolled cell growth; mutations can lead to their inactivation, allowing oncogenes to promote cancerous growth.

mutations: Changes in the DNA sequence of a gene that can lead to the formation of oncogenes or the inactivation of tumor suppressor genes.