The relationship between Bmi-1 and the epithelial-mesenchymal transition in lung squamous cell carcinoma

This study aimed to investigate the expression of Bmi-1 in lung squamous cell carcinoma tissues and the relationship between Bmi-1 and the epithelial-mesenchymal transition. RT-PCR and western blot analysis were performed to detect the expression of Bmi-1, E-cadherin, and Vimentin in 56 cases of lung squamous cell carcinoma tissues and adjacent normal tissues. The positive rates of Bmi-1, E-cadherin, and Vimentin mRNA expression in lung squamous cell carcinoma tissues were 73.2, 42.9, and 58.9%, respectively; compared to the expression of these genes in adjacent normal tissues (14.3, 75.0, and 28.6%), the differences were significant (P < 0.05). The expression of Bmi-1 in lung squamous cell carcinoma tissues showed a negative correlation with that of E-cadherin (r = -0.372, P = 0.005) and a positive correlation with that of Vimentin (r = 0.315, P = 0.02). The expression of Bmi-1 and Vimentin mRNA and protein in lung squamous cell carcinoma tissues was significantly higher than that in adjacent normal tissues (P < 0.05), and the expression of Bmi-1 and Vimentin in patients with lymph node and distal metastasis was significantly higher than that in patients without lymph node and distal metastasis (P < 0.05). The expression of E-cadherin mRNA and protein in lung squamous cell carcinoma tissues was significantly lower than that in adjacent normal tissues (P < 0.05), and the expression in patients with lymph node and distal metastasis was significantly lower than that in patients without lymph node and distal metastasis (P < 0.05). The expression of Bmi-1, E-cadherin, and Vimentin was not associated with the patient's sex, age, tumor size or degree of tumor differentiation (P > 0.05). The increase in Bmi-1 expression was accompanied by the down-regulation of E-cadherin expression and up-regulation of Vimentin expression. Bmi-1 may be associated with the epithelial-mesenchymal transition in lung squamous cell carcinoma and the occurrence, invasion, and metastasis of lung squamous cell carcinoma.