THE CLINICAL ROLE OF MDR1 GENE-EXPRESSION IN HUMAN LUNG-CANCER

Human P-glycoprotein (Pgp) encoded by the MDR1 gene confers multidrug resistance to cancel cells. The clinical role of MDR1/Pgp in lung canc er is not fully understood. A total of 87 lung cancel surgical tissue samples, including previously untreated 84 non-small-cell (NSCLC) and three small-cell lung carcinoma (SCLC), were analyzed for levels of MD R1 mRNA deter-mined by Northern blotting and compared with MDR1-positi ve cell lines. Fifteen per cent (13/87) of the armors were positive fo r the MDR1 gene, but the level was low in all samples except in one ad enocarcinoma which expressed a high level of MDR1. The gene expression in these tumors did not relate with any pathologic factors such as hi stologic type, pathologic stage and tumor size. The SCLC and only one of the 14 MDR1-negative NSCLC responded to adjuvant chemotherapy after surgery. The present results indicate that the MDR1 gene is not assoc iated in NSCLC with tumor progression and drug resistance.