Abstract: OBJECTIVE： To explore correlations between EGFR mutation status and expressions of CXCR4， Ki67， MDM2 and N-cadherin in lung adenocarcinoma cells from pleural effusion. METHODS： Tumor cells from pleural effusions of lung adenocarcinomas were diagnosed using HE staining and immunocytochemistry (ICC). EGFR gene mutation status of lung adenocarcinoma patients was detected by the amplification refractory mutation system (ARMS) method，and divided into EGFR-TKI sensitive mutation group and EGFR wild- type group. Expressions of CXCR4，Ki67，MDM2 and N- cadherin were detected using the ICC technique，and the correlations between the expression levels of these proteins and EGFR mutation status were analyzed. RESULTS：In 46 patients with malignant pleural effusion，31 patients (67.4%) harbored EGFRTKI-sensitive mutations. The expression levels of CXCR4，Ki67，MDM2，and N-cadherin were correlated with EGFR mutation status (r=0.452， 0.428， 0.417， 0.524， respectively， P<0.05). CONCLUSION： Expression levels of CXCR4， Ki67， MDM2 and N-cadherin were correlated with EGFR mutation status. Furthermore， expression levels of CXCR4，Ki67，MDM2 and N-cadherin in lung adenocarcinoma cells with pleural effusions were higher in tumors with EGFR mutation than without mutation.

Key words: pleural effusion, EGFR, CXCR4, Ki67, MDM2, N-cadherin