Distribution of multidrug resistance associated proteins in different histological subtypes and stages in operable non small cell lung cancer. A tissue microarray study

The aim of this retrospective study was to comparatively investigate the expression of the three drug-resistance related proteins P-glycoprotein (P-gp), multidrugresistance protein 1 (MRP1), and lung resistence protein (LRP), in non-small cell lung cancer (NSCLC) tissues using tissue microarray technology. Methods: Tumor specimens from 179 patients were analyzed by immunohistochemistry and data were statistically analyzed by SPSS. Results: The mean expression levels of tumor tissues in the case of P-gp and LRP did not exceed the one of normal epithelia, while MRP1 was significantly enhanced in NSCLC. No associations were observed between higher grading and P-glycoprotein expression (p <0.8) as well as lower grading and MRP1 expression in the case of adenocarcinoma (p <0.05). We also did not find any association between the immunohistochemical expression of MrP1, Lrp, Pgp, grading and staging. Conclusions: Ourdata point towards a major role of MRP1 in the intrinsic reatment resistance of NSCLC.