Expression of interleukin-6 is associated with epithelial-mesenchymal transition and survival rates in gallbladder cancer

Abstract

The present study aimed to investigate the expression of interleukin-6 (IL-6) in gallbladder cancer (GBC) tissues and its correlation with survival rate. The association between IL-6 and epithelial-mesenchymal transition (EMT)-associated markers was also examined. Using immunohistochemistry, reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, the protein and mRNA expression levels of IL-6, Twist, E-cadherin and Vimentin in 20 GBC tissues were analyzed. The IL-6, Twist and Vimentin proteins were overexpressed in 40, 20 and 70% of the human GBC samples, respectively. The protein expression of E-cadherin was higher in only 5% of the GBC samples. These differences were significant (P<0.05). Western blot analysis also revealed overexpression of IL-6, Twist and Vimentin and underexpression of E-cadherin in the GBC samples with poor differentiation, local invasion and a higher tumor-node-metastasis (TNM) stage (P<0.05). Higher mRNA expression levels of IL-6, Twist and Vimentin and a reduced expression level of E-cadherin were also demonstrated in the GBC tissues (P<0.05). The degree of differentiation, local invasion, lymph node metastasis and clinical stage were significantly associated with the mRNA expression levels of IL-6, Twist and E-cadherin. The increased expression levels of IL-6 and Twist and the reduced expression of E-cadherin correlated with shorter median survival rates (P<0.05). Line regression results revealed correlation among the mRNA expression levels of IL-6, Twist, E-cadherin and Vimentin. To the best of our knowledge, the present study is the first to demonstrate that IL-6 is associated with EMT-associated markers, tumor differentiation, local invasion, TNM stage and survival rates in GBC.