title: Clinical significance of retinoblastoma protein (pRB) expression in esophageal squamous cell carcinoma.
abstract: OBJECTIVE
  The goal was to evaluate the clinicopathological significance of retinoblastoma gene product (pRB) expression in esophageal squamous cell carcinoma.
  
  
  METHODS
  We investigated abnormal pRB expression in tumors in 191 patients using an immunohistochemical method in conjunction with anti-RB protein antibody. Surgically resected esophageal squamous cell carcinomas were examined by immunohistochemical analysis for altered pRB expression.
  
  
  RESULTS
  Decreased pRB nuclear staining indicating loss of RB function occurred in 82 (43%) of the cases studied. The incidence of decreased pRB expression was higher in tumors with invasion to the adventitia (50%) than in tumors without invasion to the adventitia (33%, P = 0.0188). In addition, the incidence of decreased pRB expression was higher in tumors with lymph node metastasis (50%) than in those without (34%, P = 0.0346). The 3-year survival rates of 82 patients who had tumors with decreased pRB expression (30%) was significantly lower than that of 109 patients who had tumors with normal pRB expression (52%, P = 0.0032). However, in the multivariate survival analysis, pRB expression was not an independent prognostic factor for patients with esophageal squamous cell carcinoma.
  
  
  CONCLUSIONS
  Abnormal pRB expression appears to be closely associated with tumor development. However, the existence of tumors with hyperphosphorylated RB protein (inactivated form) in pRB-positive tumors, such as those in the present study, should be considered. Thus, discrimination of this hyperphosphorylated form of RB protein from the unphosphorylated RB protein is needed.
authors.affiliation: Department of Surgery I, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ikeguchi
authors.forename: S
authors.initials: S
authors.lastname: Oka
authors.forename: Y
authors.initials: Y
authors.lastname: Gomyo
authors.forename: S
authors.initials: S
authors.lastname: Tsujitani
authors.forename: M
authors.initials: M
authors.lastname: Maeta
authors.forename: N
authors.initials: N
authors.lastname: Kaibara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000401:mortality / Q000556:secondary; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D016016:Proportional Hazards Models; D016160:Retinoblastoma Protein / Q000378:metabolism*; D012307:Risk Factors; D015996:Survival Rate
chemical_list: D016160:Retinoblastoma Protein