Oncogenes

Definition

Oncogenes are mutated forms of normal genes, known as proto-oncogenes, that drive the growth and proliferation of cancer cells. They play a critical role in the development of cancer by promoting uncontrolled cell division, often by encoding proteins that stimulate cell cycle progression or inhibit apoptosis. The activation of oncogenes can be caused by various factors, including genetic mutations, chromosomal rearrangements, and viral infections.

5 Must Know Facts For Your Next Test

1. Oncogenes can be activated by point mutations, amplifications, or translocations, leading to their overexpression or abnormal function.
2. Examples of well-known oncogenes include RAS, MYC, and HER2, each associated with different types of cancers.
3. The activation of oncogenes can result in pathways that promote cell survival and proliferation, allowing cancer cells to evade normal regulatory mechanisms.
4. Oncogenes can interact with various signaling pathways, including those involved in growth factor signaling and cell cycle regulation.
5. Targeted therapies have been developed to inhibit specific oncogenes or their pathways, providing personalized treatment options for cancer patients.

Review Questions

• How do oncogenes contribute to the process of carcinogenesis?
  • Oncogenes contribute to carcinogenesis by promoting uncontrolled cell growth and division. When proto-oncogenes undergo mutations or alterations, they become oncogenes that drive the cancerous behavior of cells. This can occur through mechanisms such as increased expression of growth factors or receptors, leading to persistent stimulation of cell division. As a result, normal regulatory controls on the cell cycle are bypassed, leading to tumor formation.
• What are some common mechanisms through which oncogenes are activated in cancer cells?
  • Common mechanisms of oncogene activation include point mutations, gene amplifications, and chromosomal rearrangements. Point mutations can change a single nucleotide in a proto-oncogene, resulting in a protein that drives excessive cell proliferation. Gene amplifications lead to an increased number of copies of a gene, resulting in overproduction of its protein product. Chromosomal rearrangements can fuse two genes together or relocate a proto-oncogene to a different regulatory environment, leading to dysregulated expression.
• Evaluate the implications of oncogene research on developing targeted cancer therapies.
  • Research on oncogenes has significant implications for developing targeted cancer therapies because it allows for a better understanding of the molecular mechanisms driving specific cancers. By identifying particular oncogenes associated with tumors, researchers can create drugs that specifically inhibit the activity of these genes or their downstream signaling pathways. This targeted approach not only improves treatment efficacy but also reduces side effects compared to traditional chemotherapy. As personalized medicine advances, targeting oncogenes offers promising avenues for more effective cancer treatments tailored to individual patients' tumor profiles.

Related terms

proto-oncogenes:

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

tumor suppressor genes:

Genes that normally prevent uncontrolled cell growth and division; mutations in these genes can lead to cancer development.

apoptosis:

The process of programmed cell death that removes damaged or unwanted cells, which can be disrupted by oncogenes.