High expression of E-cadherin in pleural effusion cells predicts better prognosis in lung adenocarcinoma patients.

BACKGROUND Epithelial-mesenchymal transition (EMT) is of great importance in tumor metastasis. Our previous study demonstrates that epithelial phenotype is related to epidermal growth factor receptor (EGFR) mutation and the sensitivity of EGFR tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC) patients. However, the role of EMT phenotype in malignant pleural effusions in predicting prognosis is unknown in lung adenocarcinoma patients. METHOD Pleural effusions of lung adenocarcinoma patients were collected and made into cell block (CB). EGFR mutation was detected using amplification refractory mutation system (ARMS) PCR method and H-score system was applied to evaluate the staining intensity of EMT marker and tumor cell ratio. RESULTS Forty-three CB samples, including 22 samples before any treatment (baseline, group 1) and 21 with disease progression (group 2) after first-line chemotherapy, were enrolled in this study. The expression of N-cadherin and vimentin were low in the CB tumor cells. There was no significant difference in the tumor cell radio and E-cadherin expression in the two groups. E-cadherin expression had no association with sex, age and smoking status and also patient response in both the two groups. However, high E-cadherin expression was related to EGFR mutation (P=0.032) and long progression-free survival (PFS) (P=0.015) in group 1 but not group 2 samples. CONCLUSION E-cadherin expression in CB samples was associated with EGFR mutation status and patient prognosis in lung adenocarcinoma patients in first-line chemotherapy.