High rate of <i>MDR</i>‐1 and heterogeneous pattern of <i>MRP</i> expression without gene amplification in endometrial cancer

Abstract The present study was undertaken to determine the pattern of expression of 2 molecular markers of multidrug resistance, the MDR ‐I and MRP genes, in endometrial carcinomas from 50 untreated patients using a PCR semi‐quantitative assay. In addition, PCR analysis of MDR ‐I and MRP gene amplification was obtained in each case. High rate of MDR ‐I expression without gene amplification was detected in all endometrial‐carcinoma samples, as well as in 10 adenomatous hyperplasias and 50 samples of normal endometrium. On the other hand, MRP appeared to be expressed at moderate levels in normal endometrial tissue, while relatively high levels of MRP expression without gene amplification were occasionally observed in endometrial‐carcinoma samples. © 1995 Wiley‐Liss, Inc .