Expression of a multidrug resistance gene in esophageal adenocarcinoma. Correlation with response to chemotherapy and comparison with gastric adenocarcinoma.
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.
Robey-Cafferty
S S
SS
Department of Pathology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Rutledge
M L
ML
Bruner
J M
JM
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
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000911:Antibodies, Monoclonal; D008562:Membrane Glycoproteins