Oncogenes

Definition

Oncogenes are mutated forms of normal genes called proto-oncogenes that have the potential to cause cancer. They play a crucial role in regulating cell growth and division, and when they become activated through mutations, they can lead to uncontrolled cell proliferation and tumor formation. Understanding oncogenes is essential for grasping how disruptions in the cell cycle can contribute to cancer development.

5 Must Know Facts For Your Next Test

1. Oncogenes can be activated by various factors including point mutations, gene amplifications, or chromosomal rearrangements.
2. The protein products of oncogenes often promote excessive cell division and can inhibit apoptosis, allowing cancer cells to survive longer than they should.
3. Common examples of oncogenes include RAS, MYC, and HER2, which are associated with various types of cancers.
4. Targeted therapies have been developed to inhibit the activity of specific oncogenes, providing new treatment options for cancer patients.
5. The study of oncogenes has led to significant advancements in cancer research and has improved our understanding of how genetic alterations contribute to the disease.

Review Questions

• How do mutations in proto-oncogenes lead to the formation of oncogenes and what impact does this have on the cell cycle?
  • Mutations in proto-oncogenes can convert them into oncogenes, which leads to the activation of pathways that promote uncontrolled cell growth and division. This can disrupt the normal regulation of the cell cycle, causing cells to bypass checkpoints that usually prevent inappropriate proliferation. As a result, cells may continue to divide uncontrollably, ultimately leading to tumor formation.
• Discuss the relationship between oncogenes and tumor suppressor genes in the context of cancer development.
  • Oncogenes and tumor suppressor genes work in opposition to each other in regulating cell growth. Oncogenes promote cell division and survival, while tumor suppressor genes typically inhibit these processes. When oncogenes become activated due to mutations and tumor suppressor genes are simultaneously inactivated, the balance shifts towards excessive cell growth. This imbalance is a critical factor in cancer development as it leads to the unchecked proliferation of malignant cells.
• Evaluate the role of targeted therapies in cancer treatment concerning specific oncogenes and their significance in clinical outcomes.
  • Targeted therapies have been developed to specifically inhibit the action of certain oncogenes, such as HER2 in breast cancer or BRAF in melanoma. By focusing on these molecular targets, treatments can effectively reduce tumor growth while minimizing damage to normal cells. The significance of these therapies is evident in improved clinical outcomes for patients with specific oncogene-driven cancers, as they offer more personalized treatment options that enhance therapeutic efficacy while reducing side effects.

Related terms

proto-oncogenes:

Normal genes that regulate cell growth and differentiation, which can become oncogenes when mutated.

tumor suppressor genes:

Genes that normally prevent cell division or promote apoptosis, which can counteract the effects of oncogenes when functioning properly.

carcinogenesis:

The process by which normal cells are transformed into cancer cells, often involving mutations in oncogenes and tumor suppressor genes.