Downregulated vimentin and upregulated E-cadherin in T1 stage non-small-cell lung cancer: does it suggest a mesenchymal-epithelial transition?

Lung cancer has been a major threat to human health worldwide. Vimentin (VIM) and E-cadherin (E-cad) are molecular markers that play important roles in epithelial-mesenchymal transition (EMT), which has been shown to be correlated with tumor progression. Herein, we investigated the associations between clinicopathological parameters and VIM/E-cad expression in primary T1 stage non-small cell lung cancer (NSCLC). Real-time PCR was performed on RNA extracted from tumor tissue isolated from 54 patients with T1 stage NSCLC. Immunohistochemistry was used to measure the protein levels of VIM and E-cad. The paired-samples t-test, independent-samples t- test, Kappa test, and nonparametric test were used to perform statistical analyses. The expression of VIM were lower (P<0.001) and that of E-cad was higher (P<0.001) in tumor tissue when compared with the normal tissue at the transcriptional level. The RNA of VIM in adenocarcinomas was significantly higher than that found in squamous cell carcinomas (P<0.01). Moreover, the level of metastasis observed in the lymph node was significantly higher than that observed in metastasis outside of the lymph node (P<0.05). Vimentin protein had a lower profile in the tumor tissue, and the protein level of E-cad was higher in the tumor tissue. The IHC score of VIM in tumor tissue was found associated with both the pathological type and smoke index, and the score of E-cad was found to be related to visceral pleura involvement. In conclusions, VIM is downregulated and E-cad is upregulated in T1 stage NSCLC. Our study results suggest that a mesenchymal-epithelial transition may take place in the early-stage of tumor development, and that EMT occurs when the tumor develops into a certain stage.