Objectives: E-cadherin and its associated intracellular molecules, catenins, are important for cell-cell adhesion. Impaired expression of these molecules are frequently observed in several cancers. E-cadherin and beta-catenin are often expressed in non-small cell lung cancers. The aim of this study was to investigate the expressions of E-cadherin and beta-catenin and their significance as prognostic markers in pathological stage I non-small cell lung cancer.
Methods: Paraffin embedded tumor tissue blocks were obtained from 141 patients who underwent resection without preoperative radiotherapy or chemotherapy with pathological stage I non-small cell lung cancer. Tumor samples were prepared in tissue microarrays and they were stained by immunohistochemistry with antibodies against E-cadherin and beta-catenin. The expressions of E-cadherin and beta-catenin were analyzed with relation to the clinico-pathological data. The median follow-up period of the patients was 41 months (range, 2-88 months).
Results: Preserved expressions of E-cadherin and beta-catenin were observed in the membrane and the cytoplasm of normal epithelial cells and tumor cells. Absent or reduced expression for E-cadherin and beta-catenin were observed in 60% and 45% of all the patients, respectively. There was a significant positive correlation between E-cadherin and beta-catenin expression (P<0.01). Absent or reduced expression of E-cadherin was observed in 72.5%, 36.6%, and 60.0% of squamous cell carcinoma, adenocarcinoma, and bronchioloalveolar carcinoma, respectively. There was a significant decrease of E-cadherin expression in squamous cell carcinoma compared to adenocarcinoma (P<0.01). Patients with reduced expression of beta-catenin had poor recurrence free survival in adenocarcinoma, but not in squamous cell carcinoma.
Conclusion: Decreased expressions of E-cadherin and beta-catenin were closely correlated in resected stage I non-small cell lung cancer. Reduced expression of E-cadherin and beta-catenin indicates tumor cell dedifferentiation and reduced expression of beta-catenin had poor recurrence free survival in adenocarcinoma of the resected stage I non-small cell lung cancer.