Abstract: Objective:To investigate the expression of claudin-1 protein in gallbladder carcinoma and analyze its possible relationshipwith clinicopathological characters.Methods:The expression of claudin-1 was detected by immunohistochemistry method in 47 cases of primary gallbladder carcinoma,18 cases of gallbladder adenoma and 15 cases of chronic cholecystitis.The results were analyzed.Results:The positive expression rates of claudin-1 in primary gallbladder carcinoma,gallbladder adenoma and chronic cholecystitis were 89.4%,27.8% and 26.7%,respectively.There was significant difference among all the groups of gallbladder carcinoma and gallbladder adenoma or gallbladder cholecystitis(P＜ 0.01),but no statistics significance between groupin gallbladder adenoma and gallbladder cholecystitis(P＞0.05).The expression of claudin-1 in gallbladder carcinoma had no significant with patient's age,gender,and histologic type of carcinoma(p＞0.05).The level of claudin-1 expression was higher in pathological grade(Ⅱ-Ⅲ) groupthan that in pathological grade Ⅰ group(P＜ 0.05).The level of its expression was significantly higher in Nevin stage(Ⅳ -Ⅴ) groupthan that in Nevin stage(Ⅰ-Ⅲ) group(P＜ 0.01),and higher in lymph node or distant metastasis groupthan in non-metastasis group(P＜ 0.05).Conclusions:The expression of claudin-1 in gallbladder carcinoma can provide tips of the biological behavior of gallbladder carcinoma cells.