Objective: To detect expression of lung resistance protein (LRP), multidrug resistance-associated protein(MRP) and multidrug resistance 1(MDR1) mRNA, and its clinical significance in non-small-cell lung cancer (NSCLC).
Methods: RT-PCR was used to investigate mRNA expression of the above mentioned genes.
Results: The frequency of expression of LRP, MRP and MDR1 was 74.2%, 80.3% and 37.9%, respectively. A significant positive correlation was observed between LRP and MRP(r = 0.47, P = 0.001), but this association was found neither between LRP and MDR1, nor between MRP and MDR1. The expression of LRP, MRP and MDR1 did not vary with the grade of cell differentiation and TNM staging. In adenocarcinomas which responded to chemotherapy, there was lowered expression of both LRP and MRP than those which did not respond. In chemo-responsive squamous-cell carcinomas, however, this was true of LRP expression only. The median survival time of NSCLC patients with co-expressed 2 and 3 drug resistance related genes was significantly reduced.
Conclusion: The intrinsic multidrug resistance of NSCLC involves the combined effects of LRP, MRP and MDR1.