title: p21Waf1/Cip1 expression is a prognostic marker in curatively resected esophageal squamous cell carcinoma, but not p27Kip1, p53, or Rb.
abstract: BACKGROUND
  p21Waf1/Cip1 (p21), p27Kip1 (p27), p53, and Rb play critical roles in cell cycle regulation and may influence the clinical behavior of tumors. We examined whether their expression is useful to predict survival of patients with esophageal squamous cell carcinoma (ESC).
  
  
  METHODS
  Expression of p21, p27, p53, and Rb was studied by the immunohistochemical method in specimens from 62 patients with curatively resected ESC tumors and scored by a computerized image analysis system.
  
  
  RESULTS
  The median expression scores of p21, p27, p53, and Rb (14, 12, 27, and 50, respectively) were used as cut-off points to define low and high expression groups for each protein. The 5-year survival rate for the high p21 expression group was 68%; that for the low expression group was 31% (P = .0062). p27, p53, and Rb were not correlated with overall survival. When patients were categorized into four groups based on p21 expression level and lymph node involvement (pN), the survival curves were significantly different (P = .0017). Thus, patients without lymph node involvement but with low p21 expression had survival similar to that of patients with lymph node involvement and high p21 expression. Multivariate analysis showed that age (P = .0102), lymph node involvement (P = .0076), and p21 (P = .0276) were independent prognostic factors.
  
  
  CONCLUSIONS
  Expression of p21 is an independent prognostic factor in curatively resected ESC. Definition of new subgroups of patients based on p21 expression may help to enhance the stratification of stage.
authors.affiliation: Department of Surgical Oncology, Graduate School, Faculty of Medicine, The University of Tokyo, Japan.
authors.forename: M E
authors.initials: ME
authors.lastname: Nita
authors.forename: H
authors.initials: H
authors.lastname: Nagawa
authors.forename: O
authors.initials: O
authors.lastname: Tominaga
authors.forename: N
authors.initials: N
authors.lastname: Tsuno
authors.forename: K
authors.initials: K
authors.lastname: Hatano
authors.forename: J
authors.initials: J
authors.lastname: Kitayama
authors.forename: T
authors.initials: T
authors.lastname: Tsuruo
authors.forename: C E
authors.initials: CE
authors.lastname: Domene
authors.forename: T
authors.initials: T
authors.lastname: Muto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000401:mortality / Q000601:surgery; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000601:surgery; D005260:Female; D016161:Genes, Retinoblastoma; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins
chemical_list: D014408:Biomarkers, Tumor; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D008869:Microtubule-Associated Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27