title: [Relationship between the expression of cell cycle regulators and microsatellite instability in colorectal carcinomas].
abstract: OBJECTIVE
  To explore the relationship between the expression of cell cycle regulators and microsatellite instability (MSI) in colorectal carcinomas(CRC).
  
  
  METHODS
  The expression of cell cycle regulators cyclin D1, P16, P21WAF1/CIP1, P53, Rb and PCNA were detected by immunohistochemical staining, and MSI at six microsatellite loci (D18S34, D17S799, D5S409, TCF-2, Rb and P53) were examined by PCR-SSLP in 56 cases of colorectal carcinomas.
  
  
  RESULTS
  The overall positive rate of MSI of CRC was 44.6% (25/56). MSI was positive at 1 locus in 7 cases, at 2 and more than 2 loci in 18 cases. In CRC with MSI, the positive rate of cyclin D1 and P53 protein was significantly lower, while that of P21 protein was significantly higher than those without MSI (P < 0.05). The positive rate of P16 in CRC with MSI was higher than those without MSI. The expression of Rb proteins was similar in frequency in CRC with or without MSI.
  
  
  CONCLUSIONS
  Overexpression of P21 may play an important role in MSI genesis in CRC. It may also be related to decreased expression of cyclin D1 and P53 and overexpression of P16.
authors.affiliation: Department of Pathology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: X
authors.initials: X
authors.lastname: Yan
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.forename: D
authors.initials: D
authors.lastname: Fang
mesh_terms: D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000096:biosynthesis* / Q000235:genetics; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D019938:Cyclin D1 / Q000096:biosynthesis; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D018895:Microsatellite Repeats / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis
chemical_list: C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016159:Tumor Suppressor Protein p53; D019938:Cyclin D1