Editing Placenta (section)

=== Gene and protein expression ===
{{Further |Bioinformatics#Gene and protein expression}}
About 20,000 protein coding genes are expressed in human cells and 70% of these genes are expressed in the normal mature placenta.<ref>{{Cite web|url=https://www.proteinatlas.org/humanproteome/placenta|title=The human proteome in placenta - The Human Protein Atlas|website=www.proteinatlas.org|access-date=2017-09-26|url-status=live|archive-url=https://web.archive.org/web/20170926191014/https://www.proteinatlas.org/humanproteome/placenta|archive-date=2017-09-26}}</ref><ref>{{cite journal | vauthors = Uhlén M, Fagerberg L, Hallström BM, Lindskog C, Oksvold P, Mardinoglu A, Sivertsson Å, Kampf C, Sjöstedt E, Asplund A, Olsson I, Edlund K, Lundberg E, Navani S, Szigyarto CA, Odeberg J, Djureinovic D, Takanen JO, Hober S, Alm T, Edqvist PH, Berling H, Tegel H, Mulder J, Rockberg J, Nilsson P, Schwenk JM, Hamsten M, von Feilitzen K, Forsberg M, Persson L, Johansson F, Zwahlen M, von Heijne G, Nielsen J, Pontén F | display-authors = 6 | title = Proteomics. Tissue-based map of the human proteome | journal = Science | volume = 347 | issue = 6220 | pages = 1260419 | date = January 2015 | pmid = 25613900 | doi = 10.1126/science.1260419 | s2cid = 802377 }}</ref> Some 350 of these genes are more specifically expressed in the placenta and fewer than 100 genes are highly placenta specific. The corresponding specific proteins are mainly expressed in [[trophoblast]]s and have functions related to [[pregnancy]]. Examples of proteins with elevated expression in placenta compared to other organs and tissues are [[PEG10]] and the [[Cancer/testis antigens|cancer testis antigen]] PAGE4 and expressed in [[cytotrophoblast]]s, [[Human placental lactogen|CSH1]] and [[Kisspeptin|KISS1]] expressed in [[syncytiotrophoblast]]s, and [[PAPPA2]] and [[Major basic protein|PRG2]] expressed in extravillous trophoblasts.