Ki-67 (protein) explained

Antigen Kiel 67, also known as Ki-67 or MKI67 (marker of proliferation Kiel 67), is a protein that in humans is encoded by the gene (antigen identified by monoclonal antibody Ki-67).[1] [2] [3]

Function

Antigen KI-67 is a nuclear protein that is associated with cellular proliferation and ribosomal RNA transcription.[3] Inactivation of antigen KI-67 leads to inhibition of ribosomal RNA synthesis,[4] but does not significantly affect cell proliferation in vivo: Ki-67 mutant mice developed normally and cells lacking Ki-67 proliferated efficiently.[5]

Use as a marker of proliferating cells

The Ki-67 protein (also known as MKI67) is a cellular marker for proliferation,[6] and can be used in immunohistochemistry. It is strictly associated with cell proliferation. During interphase, the Ki-67 antigen can be exclusively detected within the cell nucleus, whereas in mitosis most of the protein is relocated to the surface of the chromosomes.[7] Ki-67 protein is present during all active phases of the cell cycle (G1, S, G2, and mitosis), but is absent in resting (quiescent) cells (G0).[8] Cellular content of Ki-67 protein markedly increases during cell progression through S phase of the cell cycle.[9] In breast cancer Ki67 identifies a high proliferative subset of patients with ER-positive breast cancer who derive greater benefit from adjuvant chemotherapy.[10] [11]

Antibody labeling

Ki-67 is an excellent marker to determine the growth fraction of a given cell population. The fraction of Ki-67-positive tumor cells (the Ki-67 labeling index) is often correlated with the clinical course of cancer. The best-studied examples in this context are prostate, brain and breast carcinomas, as well as nephroblastoma and neuroendocrine tumors. For these types of tumors, the prognostic value for survival and tumor recurrence have repeatedly been proven in uni- and multivariate analysis.

MIB-1

Ki-67 and MIB-1 monoclonal antibodies are directed against different epitopes of the same proliferation-related antigen. Ki-67 and MIB-1 may be used on fixed sections.[12] MIB-1 is used in clinical applications to determine the Ki-67 labelling index. One of its primary advantages over the original Ki-67 antibody (and the reason why it has essentially supplanted the original antibody for clinical use) is that it can be used on formalin-fixed paraffin-embedded sections, after heat-mediated antigen retrieval (see next section below).

Original Ki-67 antibody

The Ki-67 protein was originally defined by the prototype monoclonal antibody Ki-67,[13] which was generated by immunizing mice with nuclei of the Hodgkin lymphoma cell line L428. The name is derived from the city of origin (Kiel, Germany) and the number of the original clone in the 96-well plate.

Interactions

Ki-67 (protein) has been shown to interact with CBX3.[14]

See also

External links

Notes and References

  1. Web site: Entrez Gene: Antigen identified by monoclonal antibody Ki-67 .
  2. Schonk DM, Kuijpers HJ, van Drunen E, van Dalen CH, Geurts van Kessel AH, Verheijen R, Ramaekers FC . Assignment of the gene(s) involved in the expression of the proliferation-related Ki-67 antigen to human chromosome 10 . Hum. Genet. . 83 . 3 . 297–9 . October 1989 . 2571566 . 10.1007/BF00285178 . 32117144 .
  3. Bullwinkel J, Baron-Lühr B, Lüdemann A, Wohlenberg C, Gerdes J, Scholzen T . Ki-67 protein is associated with ribosomal RNA transcription in quiescent and proliferating cells . J. Cell. Physiol. . 206 . 3 . 624–35 . March 2006 . 16206250 . 10.1002/jcp.20494 . 22770145 .
  4. Rahmanzadeh R, Hüttmann G, Gerdes J, Scholzen T . Chromophore-assisted light inactivation of pKi-67 leads to inhibition of ribosomal RNA synthesis . Cell Prolif. . 40 . 3 . 422–30 . June 2007 . 17531085 . 10.1111/j.1365-2184.2007.00433.x . 6496591 .
  5. Sobecki M, Mrouj K, Camasses A, Parisis N, Nicolas E, Llères D, Gerbe F, Prieto S, Krasinska L, David A, others . The cell proliferation antigen Ki-67 organises heterochromatin . eLife . 5 . e13722 . Mar 6, 2016 . e13722 . 10.7554/eLife.13722 . 26949251 . 4841783 . free .
  6. Scholzen T, Gerdes J . The Ki-67 protein: from the known and the unknown . Journal of Cellular Physiology . 182 . 3 . 311–22 . March 2000 . 10653597 . 10.1002/(SICI)1097-4652(200003)182:3<311::AID-JCP1>3.0.CO;2-9 . 22944989 .
  7. Cuylen S, Blaukopf C, Politi AZ, Müller-Reichert T, Neumann B, Poser I, Ellenberg J, Hyman AA, Gerlich DW . Ki-67 acts as a biological surfactant to disperse mitotic chromosomes . Nature . 535 . 7611 . 308–12 . July 2016 . 27362226 . 10.1038/nature18610 . 4947524. 2016Natur.535..308C .
  8. Bruno S, Darzynkiewicz Z . Cell cycle dependent expression and stability of the nuclear protein detected by Ki-67 antibody in HL-60 cells . Cell Proliferation . 25 . 1 . 31–40 . January 1992 . 1540682 . 10.1111/j.1365-2184.1992.tb01435.x . 37050410 .
  9. Ernest Y. C. Lee . Darzynkiewicz Z, Zhao H, Zhang S, Lee MY, Lee EY, Zhang Z . Initiation and termination of DNA replication during S phase in relation to cyclins D1, E and A, p21WAF1, Cdt1 and the p12 subunit of DNA polymerase δ revealed in individual cells by cytometry . Oncotarget . 6 . 14 . 11735–50 . May 2015 . 26059433 . 10.18632/oncotarget.4149 . 4494901.
  10. Sonnenblick A, Francis PA, Azim HA, de Azambuja E, Nordenskjöld B, Gutiérez J, Quinaux E, Mastropasqua MG, Ameye L, Anderson M, Lluch A, Gnant M, Goldhirsch A, Di Leo A, Barnadas A, Cortes-Funes H, Piccart M, Crown J . Final 10-year results of the Breast International Group 2-98 phase III trial and the role of Ki67 in predicting benefit of adjuvant docetaxel in patients with oestrogen receptor positive breast cancer . European Journal of Cancer . 51 . 12 . 1481–9 . 2015 . 26074397 . 10.1016/j.ejca.2015.03.018 .
  11. Yerushalmi R, Woods R, Ravdin PM, Hayes MM, Gelmon KA . Ki67 in breast cancer: prognostic and predictive potential . The Lancet. Oncology . 11 . 2 . 174–83 . 2010 . 20152769 . 10.1016/S1470-2045(09)70262-1 .
  12. Bánkfalvi A . Comparative methodological analysis of erbB-2/HER-2 gene dosage, chromosomal copy number and protein overexpression in breast carcinoma tissues for diagnostic use. . Histopathology . 37 . 5 . 411–9 . November 2000 . 11119122 . 10.1046/j.1365-2559.2000.00984.x. 35267896 .
  13. Gerdes J, Schwab U, Lemke H, Stein H . Production of a mouse monoclonal antibody reactive with a human nuclear antigen associated with cell proliferation . Int. J. Cancer . 31 . 1 . 13–20 . 1983 . 6339421 . 10.1002/ijc.2910310104. 1764319 .
  14. Kametaka A, Takagi M, Hayakawa T, Haraguchi T, Hiraoka Y, Yoneda Y . Interaction of the chromatin compaction-inducing domain (LR domain) of Ki-67 antigen with HP1 proteins . Genes to Cells . 7 . 12 . 1231–42 . 2002 . 12485163 . 10.1046/j.1365-2443.2002.00596.x . 6802841 . free .

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