title: Changes in P-glycoprotein expression in gastric carcinoma with respect to distant gastric mucosa may be influenced by p53.
abstract: BACKGROUND
  The effectiveness of some chemotherapeutic agents used to treat gastric carcinoma patients may be impaired by the presence of P-glycoprotein (P-gp) and the status of p53. A modulation of P-gp expression by p53 or other alterations during tumorigenesis have been reported. The authors analyzed P-gp expression in relation to p53 and histopathologic features in gastric carcinoma.
  
  
  METHODS
  Forty-one resected gastric carcinomas and mucosa distant from the tumor were assessed for P-gp expression by immunohistochemistry with C494 and JSB-1 antibodies. p53 expression was also immunohistochemically assessed by DO7 antibody in tumor samples. P-gp and p53 expression were semiquantitatively analyzed according to the percentage of stained cells. Histologic type, grade, vessel invasion, and stage were also studied.
  
  
  RESULTS
  Moderate or high P-gp expression was detected in gastric carcinoma in 29 cases (71%) and in gastric mucosa remote from the tumor in 36 cases (88%). This reduction in P-gp expression was observed in 22% of the carcinomas, all but 1 being p53 immunonegative tumors. Thus, 8 (42%) of the p53 immunonegative carcinomas showed a loss of P-gp expression compared with their distant gastric mucosa. All p53 immunopositive carcinomas coexpressed P-gp. No correlation between P-gp expression and histologic type, grade, vessel invasion, or stage was found.
  
  
  CONCLUSIONS
  P-gp expression in gastric carcinomas is frequent and coexpression with p53 is found. The analysis of P-gp expression in carcinomas and distant mucosa show that it is not regulated by p53, but a loss of P-gp detected in some of these carcinomas is mainly associated with a lack of p53 protein accumulation.
authors.affiliation: Department of Pathology and Surgery, School of Medicine, Miguel Hernandez University, Alicante, Spain.
authors.forename: F J
authors.initials: FJ
authors.lastname: Lacueva
authors.forename: R
authors.initials: R
authors.lastname: Calpena
authors.forename: J
authors.initials: J
authors.lastname: Medrano
authors.forename: A
authors.initials: A
authors.lastname: Teruel
authors.forename: M J
authors.initials: MJ
authors.lastname: Mayol
authors.forename: M L
authors.initials: ML
authors.lastname: Graells
authors.forename: M V
authors.initials: MV
authors.lastname: Camarasa
authors.forename: M T
authors.initials: MT
authors.lastname: Perez-Vazquez
authors.forename: J A
authors.initials: JA
authors.lastname: Ferragut
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis* / Q000235:genetics; D005753:Gastric Mucosa / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D016158:Genes, p53 / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016159:Tumor Suppressor Protein p53