Objective: To explore the expression of ezrin protein in human non-small cell lung cancer (NSCLC) tissues and lung cancer cell lines, and the association between the expression of ezrin protein and the expression of E-cadherin and CD44V6 proteins.
Methods: The expression of ezrin protein and mRNA in lung cancer cell lines was detected by RT-PCR and Western blotting. Ezrin, E-cadherin and CD44V6 were detected by immunohistochemical SP staining in tumor tissues from 150 lung cancer cases and in adjacent normal lung tissues from 30 patients. Furthermore, the expression of ezrin in 30 freshly-taken NSCLC tissues was also detected by Western blot.
Results: The expression of ezrin protein and mRNA was up-regulated in highly metastatic human lung cancer. The positive rate of ezrin, E-cadherin and CD44V6 expression in the lung cancer was 61.3%, 54.0% and 58.7%, respectively. The up-regulation of ezrin expression was significantly correlated with lymph node metastasis, but not correlated with age, sex, tumor size, histological type, clinical TNM system and pathological grade. Western blot analysis showed that the level of ezrin in the NSCLC tissues was significantly higher than that in the normal tissues (t = 5.013, P < 0.01). Survival analysis showed that the 5-year survival rate of patients with negative ezrin expression was 29.3%, significantly higher than that of patients with positive ezrin expression (15.2%, χ(2) = 4.128, P = 0.042). Multivariate Cox regression analysis showed that ezrin expression (RR = 3.012, P = 0.047) and lymph node metastasis (RR = 4.827, P = 0.035) were significantly independent prognostic factors for patients with lung cancer. Furthermore, a negative correlation was observed between the expressions of ezrin and E-cadherin in lung cancer, and a positive correlation between the expressions of ezrin and CD44V6 in lung cancer.
Conclusions: Ezrin, E-cadherin and CD44V6 play an important role in the regulation of growth and meastasis of lung cancer. Combined detection of ezrin, E-cadherin and CD44V6 expression is helpful in evaluating the metastasis and prognosis of non-small cell lung cancer.