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

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.