Editing Sarcoma (section)

== Mechanisms ==
The mechanisms by which healthy cells transform into cancer cells are described in detail elsewhere (see [[Cancer]] main page; [[Carcinogenesis]] main page). The precise molecular changes that result in sarcoma are not always known, but certain types of sarcomas are associated with particular genetic mutations.<ref name=":1" /><ref name=":2" /> Examples include:
* Most cases of Ewing sarcoma are associated with a [[chromosomal translocation]] in which part of [[chromosome 11]] fuses with part of [[chromosome 22]].<ref name=":1" /> This results in the [[Ewing sarcoma breakpoint region 1|''EWSR1'' gene]] becoming fused to other genes, including the [[FLI1|''FLI1'' gene]] in 90% of Ewing cases and [[ERG (gene)|''ERG'' gene]] in 5-10% of cases.<ref name=":1" /> These fusions result in the production of abnormal proteins, although how these abnormal proteins result in cancer is not fully known.<ref name=":1" />
* Dermatofibrosarcoma protuberans often is associated with a chromosomal translocation in which the [[Collagen, type I, alpha 1|''COL1A1'' gene]] becomes fused to the [[PDGFRB|''PDGFRB'' gene]].<ref name=":2" /> This results in over-active [[Platelet-derived growth factor|PDGF]] signaling, which is thought to promote cell division and ultimately lead to tumor development.<ref name=":2" />
* Inflammatory myofibroblastic tumor often is associated with rearrangements of the [[Anaplastic lymphoma kinase|''ALK'' gene]], and occasionally with rearrangements of the [[HMGA2|''HMGA2'' gene]].<ref name=":2" />
* Tenosynovial giant cell tumor (not a sarcoma, but a non-metastasizing and locally aggressive soft tissue tumor) frequently is associated with a chromosomal translocation between [[chromosome 1]] and [[chromosome 2]], in which the [[Macrophage colony-stimulating factor|''CSF1'' gene]] becomes fused with the [[Collagen, type VI, alpha 3|''COL6A3'' gene]].<ref name=":2" /> This results in increased CSF1 protein production, which is thought to play a role in cancer development.<ref name=":2" />
* Many liposarcomas are associated with amplification of part of chromosome 12, which results in extra copies of known cancer-promoting genes ("[[oncogene]]s") such as the [[Cyclin-dependent kinase 4|''CDK4'' gene]], the [[Mdm2|''MDM2'' gene]] and the [[HMGA2|''HMGA2'' gene]].<ref name=":2" />