title: Expression of a multidrug resistance gene in esophageal adenocarcinoma. Correlation with response to chemotherapy and comparison with gastric adenocarcinoma.
abstract: The resistance of malignant tumors to chemotherapy is often associated with overexpression of the multidrug resistance gene MDR. Its gene product, P-glycoprotein, acts as a drug efflux pump for chemotherapeutic agents. The authors studied MDR expression in 28 adenocarcinomas arising in Barrett's esophagus (EAs) using a monoclonal antibody directed against this gene product. The results were compared with MDR expression in 27 gastric adenocarcinomas (GAs). P-glycoprotein was detected in both tumor and normal mucosa in 7 of 27 GAs and in 6 of 10 EAs that were resected without prior chemotherapy. Chemotherapy was given before surgical resection in 18 of the EAs studied. Five patients had a partial response to chemotherapy, and one had a complete eradication of his carcinoma; all of these tumors were negative for P-glycoprotein. Of 12 patients without chemotherapy response, 6 had tumors that expressed P-glycoprotein. The authors conclude that P-glycoprotein is present in EAs and GAs before exposure to chemotherapy. The presence of P-glycoprotein in tumors usually correlates with its presence in the adjacent mucosa. Its presence in tumor cells may be an indicator of lack of sensitivity to chemotherapy.
authors.affiliation: Department of Pathology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
authors.forename: S S
authors.initials: SS
authors.lastname: Robey-Cafferty
authors.forename: M L
authors.initials: ML
authors.lastname: Rutledge
authors.forename: J M
authors.initials: JM
authors.lastname: Bruner
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000230:Adenocarcinoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D004351:Drug Resistance / Q000235:genetics*; D004938:Esophageal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000235:genetics; D008875:Middle Aged; D009092:Mucous Membrane / Q000032:analysis; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000911:Antibodies, Monoclonal; D008562:Membrane Glycoproteins