Abstract:Objective To investigate the expressions of epidermal growth factor receptor (EGFR) and multi-drug resistance-associated protein (MRP), and their relationships with efficacy of chemotherapy in non-small cell lung cancer (NSCLC). Methods Immunohistochemistry (EnVision method) was used to detect the expressions of EGFR, lung resistance protein (LRP), P-glycoprotein (P-gp), MRP and glutathione S-transferase π (GST-π) in NSCLC tissues of 95 patients and 15 normal lung samples. Results The positive-expression rates of EGFR, LRP, P-gp, MRP and GST-π in the NSCLC were 50.53%, 60.00%, 40.00%, 41.05% and 55.79% respectively. EGFR in the NSCLC tissues was significantly correlated with the history of smoking, pathological types of cancer (squamous cell carcinoma vs adenocarcinoma), presence of lymph node metastasis and TNM stages (P < 0.05). The positive-expression rates of LRP and MRP in the adenocarcinomas were higher than those in the squamous cell carcinomas (P < 0.05), and the expression rate of MRP in the well-differentiated carcinomas was higher than that in the medium- and poorly-differentiated carcinomas (P < 0.05). There were positive correlations between the expressions of MRP and LRP, P-gp and GST-π in the NSCLC (r = 0.341, P =0.001; r = 0.213, P = 0.038). EGFR had no correlation with LRP, P-gp, MRP or GST-π (P > 0.05). The chemotherapy efficiency for the EGFR-negative NSCLC was 66.0%, which was significantly higher than that for the EGFR-positive NSCLC (37.5%, P < 0.05). Conclusions EGFR and MRP are over-expressed in NSCLC tissues. Multidrug resistance proteins have synergistic effects on drug resistance. EGFR could be used to objectively predict chemotherapy effect and prognosis of NSCLC.