oncogene

(noun)

any gene that contributes to the conversion of a normal cell into a cancerous cell when mutated or expressed at high levels

Related Terms

Examples of oncogene in the following topics:

  • Proto-oncogenes

    • Proto-oncogenes normally regulate cell division, but can be changed into oncogenes through mutation, which may cause cancers to form.
    • The genes that code for the positive cell cycle regulators are called proto-oncogenes.
    • Proto-oncogenes are normal genes that, when mutated in certain ways, become oncogenes: genes that cause a cell to become cancerous.
    • There are several ways by which a proto-oncogene can be converted into an oncogene .
    • Consider what might happen to the cell cycle in a cell with a recently-acquired oncogene.

  • Altered Gene Expression in Cancer

    • Another type of gene often deregulated in cancers are proto-oncogenes which are positive cell-cycle regulators.
    • When mutated, proto-oncogenes can become oncogenes and cause cancer .
    • Overexpression of the oncogene can lead to uncontrolled cell growth because oncogenes can alter transcriptional activity, stability, or protein translation of another gene that directly or indirectly controls cell growth.
    • An example of an oncogene involved in cancer is a protein called myc.
    • When mutated, proto-oncogenes can become oncogenes and cause cancer due to uncontrolled cell growth.

  • DNA Oncogenic Viruses

  • RNA Oncogenic Viruses

    • Viruses which contain RNA for their genetic material but do include DNA intermediates in their life cycle are called "retroviruses. " There are numerous RNA oncogenic viruses that have been linked to various cancer types.
    • These various oncogenic viruses include:

  • Cell Signaling and Cell Growth

    • The genes that regulate the signaling proteins are one type of oncogene: a gene that has the potential to cause cancer.
    • The gene encoding RAS is an oncogene that was originally discovered when mutations in the RAS protein were linked to cancer.
    • Cancer biologists have been able to identify many other oncogenes that contribute to the development of cancer.

  • Cancer and Transcriptional Control

    • Many transcription factors, especially some that are proto-oncogenes or tumor suppressors, help regulate the cell cycle and, as such, determine how large a cell will get and when it can divide into two daughter cells .
    • Transcription factors, especially some that are proto-oncogenes or tumor suppressors, help regulate the cell cycle; however, when regulation gives rise to cancer cells, then transcriptional control of gene expression is affected.

  • Tumor Suppressor Genes

    • Like proto-oncogenes, many of the negative cell cycle regulatory proteins were discovered in cells that had become cancerous.
    • Cells such as these daughter cells quickly accumulate both oncogenes and non-functional tumor suppressor genes.

  • Overview of Cancer

    • Oncogenes are genes that promote cell growth and reproduction, such as the gene MYC.
    • Malignant transformation can occur through the formation of novel oncogenes, the inappropriate over-expression of normal oncogenes, or by the under-expression or disabling of tumor suppressor genes.

  • Epigenetic Alterations in Cancer

    • Mechanisms of epigenetic silencing of tumor suppressor genes and activation of oncogenes include: alteration in CpG island methylation patterns, histone modifications, and dysregulation of DNA binding proteins.

  • Lung Cancer

    • Similar to many other cancers, lung cancer is initiated by activation of oncogenes or inactivation of tumor suppressor genes.
    • Mutations in the K-ras proto-oncogene are responsible for 10–30% of lung adenocarcinomas.