Oncogenes

Definition

Oncogenes are mutated forms of normal genes, known as proto-oncogenes, that have the potential to cause cancer by promoting uncontrolled cell division and growth. These mutations can arise from various factors such as genetic mutations, environmental influences, or viral infections, leading to the disruption of normal regulatory mechanisms in the cell cycle. When oncogenes become activated, they can push cells into a state of constant proliferation, making them a key player in tumor formation and cancer progression.

5 Must Know Facts For Your Next Test

1. Oncogenes can result from point mutations, chromosomal translocations, or gene amplification, each leading to the overactivity of genes that promote cell division.
2. The proteins produced by oncogenes often act as growth factors, signal transducers, or transcription factors that drive the cell cycle forward without normal regulatory controls.
3. Common examples of oncogenes include RAS, MYC, and HER2, which are frequently implicated in various types of cancer.
4. Activation of oncogenes is a key event in the multistage process of cancer development, alongside the inactivation of tumor suppressor genes.
5. Targeted therapies have been developed to inhibit the activity of specific oncogenes, showing promise in treating cancers driven by these mutations.

Review Questions

• How do mutations in proto-oncogenes lead to the development of oncogenes and subsequently affect cell division?
  • Mutations in proto-oncogenes can lead to their conversion into oncogenes by altering their function so that they promote excessive cell division. These mutations might increase the production of growth factors or enhance signal transduction pathways that push cells into continuous proliferation. As a result, normal regulatory mechanisms are bypassed, leading to unregulated cell growth and contributing to tumorigenesis.
• Discuss the relationship between oncogenes and tumor suppressor genes in the context of cancer development.
  • Oncogenes and tumor suppressor genes play opposing roles in regulating the cell cycle and maintaining normal cellular functions. While oncogenes promote cell division and survival, tumor suppressor genes act to inhibit these processes. In cancer development, it is often the case that both types of genes are affected: oncogenes are activated through mutations while tumor suppressor genes are inactivated. This dual disruption leads to a significant imbalance that favors uncontrolled cell proliferation.
• Evaluate the implications of targeted therapies aimed at oncogenes for future cancer treatments and patient outcomes.
  • Targeted therapies focusing on oncogenes represent a significant advancement in personalized medicine for cancer treatment. By specifically inhibiting the activity of mutated oncogenes, these therapies can effectively reduce tumor growth while minimizing damage to normal cells. This targeted approach not only enhances treatment efficacy but also improves patient outcomes by reducing side effects associated with conventional therapies. As research progresses, ongoing evaluations of these treatments may lead to more refined strategies tailored to individual genetic profiles.

Related terms

proto-oncogenes: Normal genes that regulate cell growth and division but can become oncogenes through mutation or overexpression.

tumor suppressor genes: Genes that normally inhibit cell division or promote apoptosis; when mutated, they lose their ability to control cell growth.

mutations: Changes in the DNA sequence that can lead to altered gene function, potentially resulting in cancer if they occur in oncogenes or tumor suppressor genes.