File Name: list of oncogenes and tumor suppressor genes .zip
Rock, Daiana D. Becker-Santos, Adam P. Sage, Erin A.
- Oncogenes and tumor suppressor genes: comparative genomics and network perspectives
- Double agents: genes with both oncogenic and tumor-suppressor functions
- 13.6: Tumor Suppressor Genes
Oncogenes and tumor suppressor genes: comparative genomics and network perspectives
An oncogene is a gene that has the potential to cause cancer. Most normal cells will undergo programmed form of rapid cell death apoptosis when critical functions are altered and malfunctioning. Activated oncogenes can cause those cells designated for apoptosis to survive and proliferate instead. If, through mutation, normal genes promoting cellular growth are up-regulated gain-of-function mutation , they will predispose the cell to cancer; thus, they are termed "oncogenes". Usually multiple oncogenes, along with mutated apoptotic or tumor suppressor genes will all act in concert to cause cancer. Since the s, dozens of oncogenes have been identified in human cancer.
Double agents: genes with both oncogenic and tumor-suppressor functions
Hormones and Cancer pp Cite as. A tumor suppressor gene may be broadly defined as a gene whose inactivation is permissive to tumorigenesis. Inactivation may occur through deletion or mutation of the DNA base sequence. Two hypotheses have been proposed to explain how mutation or deletion of tumor suppressor gene DNA sequences inactivates normal genie functions. In the Knudson hypothesis, deletion or mutation must affect both alleles of the gene in order to disable tumor suppression Knudson,
The functional role of oncogenes in human lung carcinogenesis has been investigated by transfer of activated oncogenes into normal cells or an immortalized bronchial epithelial cell line, BEAS-2B. Transfection of v-Ha-ras, Ki-ras, or the combination of myc and raf into BEAS-2B cells produced tumorigenic cell lines, while transfection of raf or myc alone produced nontumorigenic cell lines. In addition to studying the pathogenic role of oncogenes, we are attempting to define negative growth-regulating genes that have tumor-suppressive effects for human lung carcinomas. Our strategy to identify tumor-suppressor genes involves loss of heterozygosity studies, monochromosome-cell fusion, and cell-cell fusion studies. Loss of heterozygosity studies have revealed consistent allelic DNA sequence deletions on chromosome 17p in squamous cell carcinomas, while large cell carcinomas and adenocarcinomas retained this locus. Mutations in p53, a tumor-suppressor gene located on chromosome 17p, have been observed. The mechanistic role of the known tumor-suppressor genes Rb-1 and p53 in the development of human lung carcinomas is being investigated in this epithelial cell model of human bronchogenic carcinogenesis.
The use of genetically engineered mouse models harboring deletions or mutations in these genes has provided insight into how such alterations drive tumor initiation, progression, and metastasis, and how they influence responses to anticancer agents. Beyond these well-characterized alterations, there has been a recent explosion in new information regarding the molecular pathogenesis of breast cancer, and therefore a need to define the functional roles of newly described potential breast cancer genes. For example, whole-genome sequencing has identified a large number of genes with recurrent sequence alterations in human breast cancer specimens Wood et al. Moreover, gene copy number analyses have identified multiple regions of chromosomal gain or loss Chin et al. Despite, this new information about cancer-associated molecular alterations, the full characterization of their impact on breast cancer biology in vivo remains incomplete. The generation of additional mouse models with engineered mutations or transgenic expression of new candidate genes will provide important information validating their role in cancer and elucidating their specific biological activities. However, it is important to point out that the existing mouse models do not recapitulate the estrogen receptor ER -positive histological subtype of breast cancer, which is an important subset in humans.
13.6: Tumor Suppressor Genes
More than 30 genes are classified as tumor suppressors. The normal functions of these genes include repair of DNA, induction of programmed cell death apoptosis and prevention of abnormal cell division. In contrast to proto-oncogenes, in tumor suppressors it is loss-of-function mutations that contribute to the progression of cancer. This means that tumor suppressor mutations tend to be recessive, and thus both alleles must be mutated in order to allow abnormal growth to proceed. It is perhaps not surprising that mutations in tumor suppressor genes, are more likely than oncogenes to be inherited. Thus, sporadic rather than inherited mutations are the most common sources of both oncogenes and disabled tumor suppressor genes. An important tumor suppressor gene is a transcription factor named p
Two of the main types of genes that play a role in cancer are oncogenes and tumor suppressor genes. Proto-oncogenes are genes that normally help cells grow. When a proto-oncogene mutates changes or there are too many copies of it, it becomes a "bad" gene that can become permanently turned on or activated when it is not supposed to be.