Editing Bcl-2 (section)

===Cancer===
Cancer can be seen as a disturbance in the [[homeostatic]] balance between cell growth and cell death. Over-expression of anti-apoptotic genes, and under-expression of pro-apoptotic genes, can result in the lack of cell death that is characteristic of cancer. An example can be seen in [[lymphoma]]s. The over-expression of the anti-apoptotic Bcl-2 protein in lymphocytes alone does not cause cancer. But simultaneous over-expression of Bcl-2 and the proto-oncogene [[myc]] may produce aggressive [[B-cell]] malignancies including lymphoma.<ref name="pmid17179226">{{cite journal | vauthors = Otake Y, Soundararajan S, Sengupta TK, Kio EA, Smith JC, Pineda-Roman M, Stuart RK, Spicer EK, Fernandes DJ | title = Overexpression of nucleolin in chronic lymphocytic leukemia cells induces stabilization of bcl2 mRNA | journal = Blood | volume = 109 | issue = 7 | pages = 3069–3075 | date = April 2007 | pmid = 17179226 | pmc = 1852223 | doi = 10.1182/blood-2006-08-043257 }}</ref> In [[follicular lymphoma]], a [[chromosomal translocation]] commonly occurs between the fourteenth and the eighteenth [[chromosome]]s – t(14;18) – which places the Bcl-2 gene from chromosome 18 next to the [[Immunoglobulin superfamily|immunoglobulin]] heavy chain locus on chromosome 14. This fusion gene is deregulated, leading to the transcription of excessively high levels of Bcl-2.<ref name="pmid3262202">{{cite journal | vauthors = Vaux DL, Cory S, Adams JM | title = Bcl-2 gene promotes haemopoietic cell survival and cooperates with c-myc to immortalize pre-B cells | journal = Nature | volume = 335 | issue = 6189 | pages = 440–442 | date = September 1988 | pmid = 3262202 | doi = 10.1038/335440a0 | s2cid = 23593952 | bibcode = 1988Natur.335..440V }}</ref> This decreases the propensity of these cells for apoptosis. Bcl-2 expression is frequent in [[small cell lung cancer]], accounting for 76% cases in one study.<ref>{{cite journal | vauthors = Kaiser U, Schilli M, Haag U, Neumann K, Kreipe H, Kogan E, Havemann K | title = Expression of bcl-2--protein in small cell lung cancer | journal = Lung Cancer | volume = 15 | issue = 1 | pages = 31–40 | date = August 1996 | pmid = 8865121 | doi = 10.1016/0169-5002(96)00568-5 }}</ref>