Oncogenes

Definition

Oncogenes are mutated forms of normal genes, known as proto-oncogenes, that promote cell growth and division. When these genes are activated inappropriately or mutated, they can lead to uncontrolled cell proliferation, a hallmark of cancer. Understanding oncogenes is essential for grasping how cancer cells bypass the regular controls of the cell cycle, contributing to tumor development.

5 Must Know Facts For Your Next Test

1. Oncogenes can be activated by various factors, including point mutations, amplifications, and chromosomal translocations.
2. Common oncogenes include RAS, MYC, and HER2, each playing a critical role in specific cancers.
3. The activation of oncogenes leads to increased signaling pathways that drive cellular processes such as proliferation and survival.
4. Oncogenes contribute to the Hallmarks of Cancer by enabling mechanisms like evading growth suppressors and resisting cell death.
5. Targeted therapies are being developed to specifically inhibit the action of certain oncogenes in cancer treatment.

Review Questions

• How do oncogenes differ from proto-oncogenes, and what role do they play in cancer development?
  • Oncogenes are mutated or overexpressed versions of proto-oncogenes, which normally help regulate cell growth and division. When proto-oncogenes become oncogenes due to mutations, they promote uncontrolled cell proliferation. This uncontrolled growth is a key factor in the progression of cancer, as these genes can push cells to divide excessively, bypassing normal regulatory mechanisms.
• Discuss the mechanisms through which oncogenes can be activated and their implications for cancer therapy.
  • Oncogenes can be activated through various mechanisms such as point mutations that change their structure, gene amplifications that increase their expression levels, or chromosomal translocations that place them under the control of strong promoters. These changes result in enhanced signaling pathways that contribute to tumorigenesis. Understanding these mechanisms has led to the development of targeted therapies aimed at inhibiting specific oncogenic signals, which can improve treatment outcomes for patients.
• Evaluate the importance of understanding oncogenes in developing novel cancer treatments and the challenges associated with targeting them.
  • Understanding oncogenes is crucial for developing novel cancer treatments because they play a significant role in driving tumor growth and progression. Researchers aim to create therapies that specifically target oncogenic pathways to halt cancer development effectively. However, challenges arise due to the complexity of signaling networks and the potential for resistance to therapies as tumors evolve. Ongoing research is focused on overcoming these hurdles by identifying combination treatments and novel targets within oncogenic pathways.

Related terms

proto-oncogenes:

Normal genes that regulate cell growth and division, which can become oncogenes when mutated or expressed at high levels.

tumor suppressor genes:

Genes that normally inhibit cell division and prevent tumor formation; their loss or mutation can contribute to cancer progression.

mutations: Changes in the DNA sequence of a gene that can lead to alterations in gene function and potentially result in cancer.