Editing Oct-4 (section)

== In adult stem cells ==

Several studies suggest a role for Oct-4 in sustaining self-renewal capacity of [[adult stem cell|adult somatic stem cells]] (i.e. stem cells from epithelium, bone marrow, liver, etc.).<ref name="pmid15513931">For example:
* {{cite journal | vauthors = Tai MH, Chang CC, Kiupel M, Webster JD, Olson LK, Trosko JE | title = Oct4 expression in adult human stem cells: evidence in support of the stem cell theory of carcinogenesis | journal = Carcinogenesis | volume = 26 | issue = 2 | pages = 495–502 | date = February 2005 | pmid = 15513931 | doi = 10.1093/carcin/bgh321 | doi-access = free }}
* {{cite journal | vauthors = Kim JH, Jee MK, Lee SY, Han TH, Kim BS, Kang KS, Kang SK | title = Regulation of adipose tissue stromal cells behaviors by endogenic Oct4 expression control | journal = PLOS ONE | volume = 4 | issue = 9 | pages = e7166 | date = September 2009 | pmid = 19777066 | pmc = 2747014 | doi = 10.1371/journal.pone.0007166 | bibcode = 2009PLoSO...4.7166K | veditors = Mei L | doi-access = free }}</ref> Other scientists have produced evidence to the contrary,<ref>{{cite journal | vauthors = Lengner CJ, Camargo FD, Hochedlinger K, Welstead GG, Zaidi S, Gokhale S, Scholer HR, Tomilin A, Jaenisch R | title = Oct4 expression is not required for mouse somatic stem cell self-renewal | journal = Cell Stem Cell | volume = 1 | issue = 4 | pages = 403–15 | date = October 2007 | pmid = 18159219 | pmc = 2151746 | doi = 10.1016/j.stem.2007.07.020 }}</ref> and dismiss those studies as artifacts of ''in vitro'' culture, or interpreting background noise as signal,<ref>{{cite journal | vauthors = Lengner CJ, Welstead GG, Jaenisch R | title = The pluripotency regulator Oct4: a role in somatic stem cells? | journal = Cell Cycle | volume = 7 | issue = 6 | pages = 725–8 | date = March 2008 | pmid = 18239456 | doi = 10.4161/cc.7.6.5573 | url = http://www.landesbioscience.com/journals/cc/article/5573/ | doi-access = free }}</ref> and warn about Oct-4 [[pseudogene]]s giving false detection of Oct-4 expression.<ref name="pmid17379765">{{cite journal | vauthors = Zangrossi S, Marabese M, Broggini M, Giordano R, D'Erasmo M, Montelatici E, Intini D, Neri A, Pesce M, Rebulla P, Lazzari L | title = Oct-4 expression in adult human differentiated cells challenges its role as a pure stem cell marker | journal = Stem Cells | volume = 25 | issue = 7 | pages = 1675–80 | date = July 2007 | pmid = 17379765 | doi = 10.1634/stemcells.2006-0611 | s2cid = 23662657 | doi-access = free }}</ref>
Oct-4 has also been implicated as a marker of [[cancer stem cell]]s.<ref>{{cite journal | vauthors = Kim RJ, Nam JS | title = OCT4 Expression Enhances Features of Cancer Stem Cells in a Mouse Model of Breast Cancer | journal = Laboratory Animal Research | volume = 27 | issue = 2 | pages = 147–52 | date = June 2011 | pmid = 21826175 | pmc = 3145994 | doi = 10.5625/lar.2011.27.2.147 }}</ref><ref>{{cite journal | vauthors = Atlasi Y, Mowla SJ, Ziaee SA, Bahrami AR | title = OCT-4, an embryonic stem cell marker, is highly expressed in bladder cancer | journal = International Journal of Cancer | volume = 120 | issue = 7 | pages = 1598–602 | date = April 2007 | pmid = 17205510 | doi = 10.1002/ijc.22508 | s2cid = 23516214 | doi-access = free }}</ref>
A majority of Oct4 cancer stem-like cell studies (CSC) report a positive association between expression of OCT4 and chemoresistance.<ref name="Mohiuddin_2020">{{cite journal | vauthors = Mohiuddin IS, Wei SJ, Kang MH | title = Role of OCT4 in cancer stem-like cells and chemotherapy resistance | journal = Biochimica et Biophysica Acta. Molecular Basis of Disease | volume = 1866 | issue = 4 | pages = 165432 | date = April 2020 | pmid = 30904611 | pmc = 6754810 | doi = 10.1016/j.bbadis.2019.03.005 }}</ref> Chemotherapy resulting in the enrichment of CSCs showed changes in the phenotypes and increased stem cell markers of OCT4.<ref>{{cite journal | vauthors = Lee S, Wottrich S, Bonavida B | title = Crosstalks between Raf-kinase inhibitor protein and cancer stem cell transcription factors (Oct4, KLF4, Sox2, Nanog) | journal = Tumour Biology | volume = 39 | issue = 4 | pages = 1010428317692253 | date = April 2017 | pmid = 28378634 | doi = 10.1177/1010428317692253 | doi-access = free }}</ref> Various cancers such as lung cancer, bladder cancer, and mesothelioma cells with high OCT4 expressions showed resistance to cisplatin, general drug resistance, and tumor recurrence.<ref name="Mohiuddin_2020" /> Breast cancer patients had tamoxifen resistance and poor clinical outcomes associated with OCT4.<ref>{{cite journal | vauthors = Gwak JM, Kim M, Kim HJ, Jang MH, Park SY | title = Expression of embryonal stem cell transcription factors in breast cancer: Oct4 as an indicator for poor clinical outcome and tamoxifen resistance | journal = Oncotarget | volume = 8 | issue = 22 | pages = 36305–36318 | date = May 2017 | pmid = 28422735 | doi = 10.18632/oncotarget.16750 | pmc = 5482656 }}</ref>
OCT4 knock-downs increase sensitivity to cisplatin and irradiation in lung cells, retained tumorigenicity in glioma-initiating cells, and metastasis mediation in ovarian cancer.<ref name="Mohiuddin_2020" /> In in vitro studies looking at cisplatin, knock-down of OCT4 increased their sensitivity and reduced cell proliferation.<ref name="Mohiuddin_2020" /> Further investigation is needed due to the sparsity of stem cells within tumors and their heterogeneity.