title: An immunohistochemical study of p16, pRb, p21 and p53 proteins in human esophageal cancers.
abstract: BACKGROUND
  Cell cycle-associated proteins, p16, pRb, p21 and p53 are important in regulating the G1-S checkpoint in the cell cycle, and their functional alterations play key roles in carcinogenesis and cell proliferation.
  
  
  METHODS
  We immunohistochemically examined the expression of p16, pRb, p21 and p53 proteins by using surgically resected tissues from 35 patients with primary esophageal cancers.
  
  
  RESULTS
  In 35 esophageal cancers, the expressions of p16, pRb, p21 and p53 proteins were detectable in 4(11.4%), 25(71.4%), 11(31.4%) and 20(57.1%) respectively. Interestingly, 24 of 25 pRb positive cancers (96.0%) had negative p16, whereas three of ten pRb-negative cancers (30.0%) had high levels of p16 (p < 0.05). In 11 cases of p21 positive immunostaining, there was lymph node metastasis (pN1) in 9 (81.8%).
  
  
  CONCLUSIONS
  These results suggest that abnormalities of p16 protein may be closely associated with the carcinogenesis or cell proliferation of esophageal cancers.
authors.affiliation: Department of Surgery I, Gunma University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kato
authors.forename: M
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Fukai
authors.forename: K
authors.initials: K
authors.lastname: Tajima
authors.forename: N
authors.initials: N
authors.lastname: Masuda
authors.forename: K
authors.initials: K
authors.lastname: Tsukada
authors.forename: H
authors.initials: H
authors.lastname: Kuwano
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
mesh_terms: D000328:Adult; D000368:Aged; D018196:Carcinoma, Adenosquamous / Q000737:chemistry / Q000401:mortality / Q000473:pathology; D018288:Carcinoma, Small Cell / Q000737:chemistry / Q000401:mortality / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000401:mortality / Q000473:pathology; D002454:Cell Differentiation; D002455:Cell Division; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000032:analysis*; D004938:Esophageal Neoplasms / Q000737:chemistry* / Q000401:mortality / Q000473:pathology; D005260:Female; D016193:G1 Phase / Q000502:physiology*; D016161:Genes, Retinoblastoma; D019942:Genes, p16; D016158:Genes, p53; D006801:Humans; D007124:Immunoenzyme Techniques; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D009367:Neoplasm Staging; D011379:Prognosis; D016160:Retinoblastoma Protein / Q000032:analysis*; D016196:S Phase / Q000502:physiology*; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
chemical_list: C493956:CDKN1A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D009363:Neoplasm Proteins; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53