Significance of Epithelial-mesenchaymal Transition Phenotype in Invasive Tumor Front Cells of Lung Squamous Cell Carcinoma

Abstract

Background and objective The invasive tumor front (ITF) refers to cells or invasive nests in the junctional region of a tumor and its host. The ITF contains the most invasive cells of a tumor, and has a high prognostic value in carcinoma. The aim of this study is to investigate the epithelial-mesenchymal transformation phenotype in ITF cells of lung squamous cell carcinoma (SCC), and analyze the relationship between clinicopathological features and clinical outcomes of patients. Methods Semiquantitative immunohistochemistry was used to examine the expression of epithelial markers (E-cadherin and β-catenin) and mesenchymal marker (vimentin) in 104 lung SCC tumor tissues. Results A decrease in E-cadherin expression in ITF cells was observed in 56 of 104 (53.8%) tumors from patients. This result was markedly lower than that of non-ITF cells, which eventually developed metastatic tumors and were also associated with death (P=0.04). Vimentin expression was observed in 44 of 104 (42.3%) ITF cells, which was much higher than that of non-ITF cells. The downregulation of E-cadherin and overexpression of vimentin were associated with tumor invasive pattern, lymphatic metastasis, and poor prognosis (P<0.01). The expression of β-catenin was 67.3% (70/104) in ITF cells. Moreover, ITF cells showed more nuclear and plasma-positive cells, which were closely associated with metastasis (P<0.01). Conclusion The loss in expression of E-cadherin/β-catenin and overexpression of vimentin in ITF cells may be associated with poor prognosis of lung SCC patients.

Keywords

• Lung squamous cell carcinoma
• Invasive tumor front
• E-cadherin
• β-catenin
• Vimentin