Background and AimsCholangiocarcinoma is a rare tumor with an increasing incidence wordwide. The surgical resection with curative intent is the only treatment for long term survival. Different prognostic factors have been identified in surgical series but the biological behaviour of this disease has not been clarified yet. The aim of this study is to evaluate the significance of tissue expression of mucins (MUC1, MUC2, MUC5AC, MUC6) in a group of patients with hilar and intrahepatic cholangiocacinoma (ICC) submitted to surgical resection with curative intent.Patients and MethodsBetween 1990 and 2007 224 patients with cholangiocarcinoma was evaluated at a single division of surgery of the Department of Surgery and Gastroenterology of University of Verona. 120 patients underwent surgical treatment. In the 38 consecutive recently observed patients (13 with hilar cholangiocarcinoma and 25 with ICC) tissue mucin expression was evaluated in surgical specimens. All the patients with ICC were classified according to Liver Cancer Study Group of Japan macroscopic criteria (2003): Mass Forming type (MF), periductal infiltrating type (PI) and intraductal grow type (IG).ResultsMacroscopic analysis showed MF type in 11 patients (44%), PI type in 12 (48%) and mixed MF + PI in 2 cases (8%). Pathology showed lymph-nodes involvement in 11 patients (29%),perineural invasion in 24 (63%), microscopic vascular invasion in 25 (65%) and macroscopic vascular invasion in 14 (37%).Tumors were well differentiated in 4 cases, moderate in 14 and poor in 8 cases. Mucin analysis showed that MUC2 and MUC6 were not present in all specimens. MUC1 was present in 38.5 % of hilar tumors, in 41.7 % of MF ICC, in 100 % of PI ICC and in 45.5 % of MF+PI ICC. MUC5AC was present in 84.6 % of hilar cholangiocarcinoma, in 0 % of MF ICC, in 100 % of PI ICC anf in 63.6 % of MF+PI type (p=0.001). Further analyses in patients with hilar cholangiocarcinoma did not showed relationship between mucins expression and the following pathology findings: tumor diameter, lymph nodes involvement, vascular invasion and perineural invasion. Also in ICC MUC1, MUC2 and MUC6 were not related with pathology findings. Whereas expression of MUC5AC was significantly related with tumor diameter inferior to 3 cm (P = 0,01); poor differentiation degree (p=0.05) and perineural invasion (p=0.05).ConclusionsThis study identify a significant relationship between MUC5AC expression and gross type of ICC (all the MF type tumors were negative) and with pathology findings related to aggressive biological tumor behavour. Further studies are necessary to clarify the prognostic significance of MUC5AC.