Abstract: Objective To investigate the relative levels of S100A6 mRNA and its protein expression in tumorous tissues of patients with cholangiocarcinoma. Methods The tumorous tissues in 40 patients with cholangiocarcinoma in our hospital between 2008 and 2014 were collected,and liver tissues in another 40 patients with benign biliary diseases during the same period were also collected as control. S100A6 mRNA and its protein in liver tissues were detected. Serum S100A6 was assayed by ELISA. Univariate and multivariate unconditional Logistic regression analysis was made for the risk factors of high serum S100A6 levels in patients with cholangiocarcinoma. Results The expression of S100A6 protein in tumor adjacent tissues and liver tissues were positive in 8 （20%） and in 12（30%）,respectively,significantly lower than in 26（65%） in timorous tissues （P<0.05）;the relative levels of S100A6 mRNA in adjacent tissues and liver tissues were （0.92±0.33） and （1.12±0.46）,significantly lower than（1.93±0.57） in cholangiocarcinoma tissues （P<0.05）;the relative expression of S100A6 protein in tumor adjacent tissues and liver tissues was （0.56±0.16） and （0.85±0.46）,significantly lower than[（1.63±0.51）,P<0.05] in timorous tissues;serum S100A6 level in patients with cholangiocarcinoma was （2456.85±128.31） pg/ml,significantly higher than（2234.26±116.35） pg/ml in control group （P<0.05）;serum S100A6 level in patients with cholangiocarcinoma was positively correlated with CEA,CRP,invasion depth,lymph node metastasis,TNM stage and tumor differentiation （P<0.05）;multivariate Logistic regression analysis showed that tumor invasion depth,lymph node metastasis,poor TNM stage and differentiation were the risk factors for high serum S100A6 levels in patients with cholangiocarcinoma （P<0.05）. Concluson The implication of high serum S100A6 levels in patients with cholangiocarcinoma needs further investigation.

Key words: Cholangiocarcinoma, S100A6, Risk factors