# Neochromosome

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> Markdown URL: https://mediated.wiki/source/Neochromosome.md
> Source: https://en.wikipedia.org/wiki/Neochromosome
> Source revision: 1166183778
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

A '''neochromosome''' is a [chromosome](/source/chromosome) that is not normally found in nature.  [Cancer](/source/Cancer)-associated neochromosomes are found in some cancer cells.<ref name=":0">{{Cite journal | doi = 10.1016/j.ccell.2014.09.010| title = The Architecture and Evolution of Cancer Neochromosomes| journal = Cancer Cell| volume = 26| issue = 5| pages = 653–67| year = 2014| last1 = Garsed | first1 = D. W. | last2 = Marshall | first2 = O. J. | last3 = Corbin | first3 = V. D. A. | last4 = Hsu | first4 = A. | last5 = Di Stefano | first5 = L. | last6 = Schröder | first6 = J. | last7 = Li | first7 = J. | last8 = Feng | first8 = Z. P. | last9 = Kim | first9 = B. W. | last10 = Kowarsky | first10 = M. | last11 = Lansdell | first11 = B. | last12 = Brookwell | first12 = R. | last13 = Myklebost | first13 = O. | last14 = Meza-Zepeda | first14 = L. | last15 = Holloway | first15 = A. J. | last16 = Pedeutour | first16 = F. | last17 = Choo | first17 = K. H. A. | last18 = Damore | first18 = M. A. | last19 = Deans | first19 = A. J. | last20 = Papenfuss | first20 = A. T. | last21 = Thomas | first21 = D. M. | pmid=25517748| doi-access = free }}</ref><ref name=":1">{{Cite journal
 | pmid = 19795405
| year = 2009
| last1 = Garsed
| first1 = D. W.
| title = Cancer-associated neochromosomes: A novel mechanism of oncogenesis
| journal = BioEssays
| volume = 31
| issue = 11
| pages = 1191–200
| last2 = Holloway
| first2 = A. J.
| last3 = Thomas
| first3 = D. M.
| doi = 10.1002/bies.200800208
| s2cid = 42141654
}}</ref>

Neochromosomes have also been created using [genetic engineering](/source/genetic_engineering) techniques.<ref>{{Cite journal | doi = 10.1038/nature.2014.14941| title = First synthetic yeast chromosome revealed| journal = Nature| year = 2014| last1 = Callaway | first1 = E. | s2cid = 88104990| doi-access = free}}</ref><ref>{{cite web|url=http://www.nbcnews.com/science/science-news/gene-gurus-create-synthetic-yeast-chromosome-scratch-n63316|title=Gene Gurus Create Synthetic Yeast Chromosome From Scratch|author=Alan Boyle|publisher=NBC News|date=27 March 2014}}</ref>

== Cancer-associated neochromosomes ==

Cancer-associated neochromosomes are giant supernumerary chromosomes. They harbor the mutations that drive certain cancers (highly amplified copies of key [oncogene](/source/oncogene)s, such as [MDM2](/source/Mdm2), [CDK4](/source/Cyclin-dependent_kinase_4), [HMGA2](/source/HMGA2)). They may be circular or linear chromosomes. They have functional [centromere](/source/centromere)s, and [telomere](/source/telomere)s when linear. They are rare overall, being found in about 3% of cancers, but are common in certain rare cancers. For example, they are found in 90% of parosteal [osteosarcomas](/source/osteosarcomas).<ref name=":1" />

Neochromosomes from well- and de-differentiated [liposarcoma](/source/liposarcoma) have been studied at high resolution by isolation (using flow sorting) and sequencing, as well as microscopy. They consist of hundreds of fragments of DNA, often derived from multiple normal chromosomes, stitched together randomly, and contain high levels of DNA amplification (~30-60 copies of some genes).<ref name=":1" />

Using [statistical inference](/source/statistical_inference) and [mathematical model](/source/mathematical_model)ling, the process of how neochromosomes initially form and evolve has been made clearer. Fragments of DNA produced following [chromothriptic](/source/chromothripsis) shattering of [chromosome 12](/source/Chromosome_12_(human)) undergo [DNA repair](/source/DNA_repair) to form of a circular or [ring chromosome](/source/ring_chromosome). This undergoes hundreds of circular [breakage-fusion-bridge cycle](/source/breakage-fusion-bridge_cycle)s, causing random amplification and deletion of DNA with selection for the amplification of key oncogenes. DNA from additional chromosomes is somehow added during this process. Erosion of [centromere](/source/centromere)s can lead to the formation of [neocentromere](/source/neocentromere)s or the capture of new native centromeres from other chromosomes. The process ends when the neochromosome forms a linear chromosome following the capture of telomeric caps, which can be chromothriptically derived.

== References ==
{{reflist}}

Category:Oncology
Category:Genetic engineering

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{{Genetics-stub}}
{{Bioengineering-stub}}

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Adapted from the Wikipedia article [Neochromosome](https://en.wikipedia.org/wiki/Neochromosome) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Neochromosome?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.