title: High nuclear/cytoplasmic ratio of Cdk1 expression predicts poor prognosis in colorectal cancer patients.
abstract: BACKGROUND
  Cdk1 (cyclin-dependent kinase 1) is critical regulator of the G2-M checkpoint. Cyclin-dependent kinase pathways are considered possible targets for cancer treatment; however, the prognostic role of Cdk1 in colorectal cancer is still controversial. Therefore, we attempted to determine the impact of Cdk1 on the clinical outcome of colorectal cancer patients to further identify its role in colorectal cancer.
  
  
  METHODS
  Cdk1 immunoreactivity was analyzed by immunohistochemistry (IHC) in 164 cancer specimens from primary colorectal cancer patients. The medium follow-up time after surgery was 3.7 years (range: 0.01 to 13.10 years). The prognostic value of Cdk1 on overall survival was determined by Kaplan-Meier analysis and Cox proportional hazard models.
  
  
  RESULTS
  All samples displayed detectable Cdk1 expression with predominant location in the cytoplasm and nucleus. A high Cdk1 nuclear/cytoplasmic (N/C) expression ratio was correlated with poor overall survival (5-year survival rate: 26.3% vs 46.9%, N/C ratio ≥1.5 vs N/C ratio <1.5, log-rank p = 0.027). Accordingly, a Cdk1 N/C expression ratio ≥1.5 was identified as an independent risk factor by multivariate analysis (hazard ratio = 1.712, P = 0.039).
  
  
  CONCLUSIONS
  We suggest that Cdk1 N/C expression ratio determined by IHC staining could be an independent prognostic marker for colorectal cancer.
authors.forename: Wen-Wei
authors.initials: WW
authors.lastname: Sung
authors.forename: Yueh-Min
authors.initials: YM
authors.lastname: Lin
authors.forename: Pei-Ru
authors.initials: PR
authors.lastname: Wu
authors.forename: Hsu-Heng
authors.initials: HH
authors.lastname: Yen
authors.forename: Hung-Wen
authors.initials: HW
authors.lastname: Lai
authors.forename: Tzu-Cheng
authors.initials: TC
authors.lastname: Su
authors.forename: Ren-Hung
authors.initials: RH
authors.lastname: Huang
authors.forename: Chun-Kai
authors.initials: CK
authors.lastname: Wen
authors.forename: Chia-Yu
authors.initials: CY
authors.lastname: Chen
authors.affiliation: School of Medicine, Chung Shan Medical University, Taichuang, Taiwan. 132540@cch.org.tw.
authors.forename: Chih-Jung
authors.initials: CJ
authors.lastname: Chen
authors.forename: Kun-Tu
authors.initials: KT
authors.lastname: Yeh
mesh_terms: D016203:CDC2 Protein Kinase; D002467:Cell Nucleus / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D011379:Prognosis; D016016:Proportional Hazards Models; D016019:Survival Analysis
chemical_list: D016203:CDC2 Protein Kinase; C528899:CDK1 protein, human; D018844:Cyclin-Dependent Kinases