OBJECTIVE: To investigate the protein and mRNA expression of E-cadherin and beta-catenin in nonsmall cell lung carcinoma (NSCLC) and to find their correlation with histological type, differentiation, metastasis and prognosis. METHODS: High sensitive S-P immunohistochemical method and in situ hibridization were used to detect the protein and mRNA expression of E-cadherin and beta-catenin. RESULTS: Immunohistochemistry revealed that among the 101 cases, the positive rates of E-cadherin and beta-catenin were 68.3% and 81.2% respectively. The abnormal expression rates of these two proteins were 61.4% and 64.4% respectively. There was no significant relationship between E-cadherin and beta-catenin staining and histological type of the tumor (P > 0.05). However, there was a statistically significant difference between well and moderately differentiated cells and poorly differentiated cells (P < 0.05). In cases with lymphatic metastasis, the abnormal expression rates of E-cadherin and beta-catenin were significantly higher than those in nonmetastatic cases (P < 0.05). The mean survival time in cases with abnormal E-cadherin and beta-catenin expression were significantly shorter than that in cases with the expression grading (+ +) approximately (+ + +). In situ hybridization showed that in NSCLC, the positive rate of E-cadherin and beta-catenin mRNA was 38.9% and 47.2% respectively. Their concordant rates with (+ +) approximately (+ + +) protein expression were 78.6% and 82.4%, respectively. CONCLUSIONS: The concordant rate of E-cadherin and beta-catenin mRNA and protein expression was relatively high. They can be used as markers of prognosis of NSCLC in clinical practice.