AIM: To investigate the expressions of MUC1 and MUC5AC in intrahepatic cholangiocarcinoma (ICC). Association of expressions of mucins MUC1 and MUC5AC with clinical findings, metastasis, and survival of the liver fluke-associated ICC patients was determined. METHODS: The expressions of MUC1 and MUC5AC mucins were examined by immunohistochemical staining in 87 cases of histologically-proven ICC. The expressions of mucins in relationship between clinicopathological significance and prognosis of the patients were evaluated. RESULTS: Fifty-two patients (60%) exhibited both MUC1 and MUC5AC expressions, whereas 31% expressed either MUC1 or MUC5AC, and 9% expressed neither. High MUC1 immunoreactivity displayed a significant correlation with tumor progression as reflected by vascular invasion (P<0.01), whereas high expression of MUC5AC significantly correlated with neural invasion (P = 0.022) and advanced ICC stage (P= 0.008). Patients with high expression of MUC1 had a significantly shorter survival (P = 0.0002). According to multivariate analyses, MUC1 reactivity (P = 0.026), histological grading and stage of tumor represented the least probability of survival. CONCLUSION: MUC1 is overexpressed in liver fluke-associated cholangiocarcinoma and relates to vascular invasion and poor prognosis, whereas MUC5AC mucin is neoexpressed and relates to neural invasion and advanced ICC stage. High MUC1 expression in tumor may be useful for predicting the poor outcome of ICC patients. AIM: To investigate the expressions of MUC1 and MUC5AC in intrahepatic cholangiocarcinoma (ICC). Association of expressions of mucins MUC1 and MUC5AC with clinical findings, metastasis, and survival of the liver fluke-associated ICC patients was determined. METHODS: The expressions of MUC1 and MUC5AC mucins were examined by immunohistochemical staining in 87 cases of histologically-proven ICC. The expressions of mucins in relationship between clinicopathological significance and prognosis of the patients were evaluated. RESULTS: Fifty-two patients (60%) exhibited both MUC1 and MUC5AC expressions , while 31% expressed either MUC1 or MUC5AC, and 9% expressed neither. High MUC1 immunoreactivity displayed a significant correlation with tumor progression as reflected by vascular invasion (P <0.01), while high expression of MUC5AC significantly correlated with neural invasion (P = 0.022) and advanced ICC stage (P = 0.008). Patients with high expression of MUC1 had a significantly shorter su MUC1 is overexpressed in liver fluke-associated cholangiocarcinoma and related to vascular invasion and (P = 0.0002). According to the multivariate analyzes MUC1 reactivity (P = 0.026), histological grading and stage of tumor represented the least probability of survival poor prognosis, while MUC5AC mucin is neoexpressed and implicated in neural invasion and advanced ICC stage. High MUC1 expression in tumor may be useful for predicting the poor outcome of ICC patients.