Objective: To investigate expression of multidrug resistance-associated protein (MRP) in non-small cell lung cancer and its relation to histological type, TNM staging and prognosis.
Methods: In situ hybridization was used to examine mRNA expression of MRP.
Results: The overall positive rate of MRP expression was 74.1%, with 73.3% and 72.0% in adenocarcinoma and squamous-cell carcinoma, respectively. The expression of MRP was not related to histological subtypes, TNM staging and cell differentiation. In 47 patients who received chemotherapy, 35 patients with positive MRP expression(+(-)++) showed worse prognosis than in those with negative expression (P < 0.05). The median survival time was 8.7 months and 21 months in patients with positive and negative MRP expession, respectively. In patients with squamous-cell carcinoma, the survival rate was significantly lower in patients (n = 12) with positive MRP expression than in those (n = 7) with negative MRP expression (P < 0.05). Their median survival time was 6 months and 19.5 months, respectively (P < 0.05).
Conclusion: The expression of MRP gene is negatively correlated with survival of patients with squamous-cell carcinoma, but not adenocarcinoma, who received chemotherapy.