Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.44 (P-glycoprotein)
 13,344 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, 212 untreated primary pulmonary and pleural neoplasms were studied immunohistochemically with the monoclonal antibody HYB-612 which detects the multidrug resistance (MDR)-related P-glycoprotein (gp180). A tumor was considered positive for the expression of the MDR phenotype, even if a single rare positive cell was detected. Using this criterion, all of the various histologic subtypes were found to express MDR to varying degrees. The frequency of expression of this phenotype was found to be notably higher in non-small-cell carcinomas than in small-cell carcinomas. These findings are consistent with the known clinical responses of these neoplasms. The detection of gp180 in untreated lung neoplasms may be predictive of the responsiveness of neoplasms to chemotherapeutic agents. In addition, its presence or absence might be useful in determining the appropriate treatment protocol for given patients.
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PMID:Immunohistochemical analysis of pulmonary and pleural tumors with the monoclonal antibody HYB-612 directed against the multidrug resistance (MDR-1) gene product, P-glycoprotein. 247 79

Expression of the multidrug-resistant (MDR) phenotype was investigated in acute leukemia using a monoclonal antibody (HYB-241) directed against a cell surface epitope of the 180 kd P-glycoprotein (gp180) by flow cytometric analysis of clinical samples. Samples from sixty-four patients were tested (37 with acute myelocytic leukemia, 20 with acute lymphocytic leukemia, and 7 with blastic chronic myelocytic leukemia). A D value (derived from Kolmogorov-Smirnov test) greater than 0.15 was considered positive (+). Eight of 32 newly diagnosed patients were positive for gp180 compared with 22 of 32 relapsed/refractory (R/R) patients (P < 0.001). Of the new patients, vinca/anthracycline-based induction therapy failed in 3/6 gp180(+) and 5/18 gp180(-) patients. In the R/R group, 15/16 gp180(+) and 3/6 gp180(-) patients failed to achieve complete remission (P < 0.05). In vitro drug accumulation studies performed with verapamil failed to show a correlation with clinical response. However, in a subset of patients, a striking correlation (r = .97, P = .001) was noted between the presence of gp180 as determined by the D value and the functional activity of the P-glycoprotein as expressed by increased daunorubicin accumulation in the presence of verapamil. The results suggest that 1) newly diagnosed patients can express gp180, 2) P-glycoprotein is expressed in 69% of R/R patients, 3) response in R/R patients is effected by the presence of gp180, and 4) expression of gp180 is highly correlated with its function as a drug-efflux pump in a subset of the patients studied. The complexity of clinical drug resistance is underscored by the finding that the MDR model is not applicable to all cases. In such instances, other mechanisms may play a predominant role.
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PMID:Flow cytometric determination of the multidrug-resistant phenotype in acute leukemia. 800 61