Background: Cholangiocarcinoma is the most common primary cancer of liver in North-Eastern region of Thailand. Human epidermal growth factor receptor-2 (HER-2) overexpression is a poor prognostic factor of many types of cancer but there is limited data in cholangiocarcinoma. This study aimed to investigate prevalence of HER-2 overexpression in cholangiocarcinoma and analyzed its association with overall survival and clinicopathological features.

Material and Method: This study was retrospective cohort analytical single-centered study which included adult patients with cholangiocarcinoma in Srinagarind hospital, Khon Kaen, Thailand. Archived pathological tissue diagnosed as cholangiocarcinoma were stained for HER-2 using a labeled streptavidin biotin peroxidase method with the polyclonal antibody (Dako A0485) and classified into positive and negative group as, in this study, 3+ and 0, 1+, 2+ by immunohistochemistry results, respectively. Prevalence of HER-2 overexpression was presented with percentage and 95% confidence interval (95% CI).

Results: A total of 93 cases, of which 71% were male, were included. Mean age was 63 and 62 years in HER-2 positive and negative groups, respectively. The proportion of intrahepatic was more than extrahepatic cholangiocarcinoma (72% vs 28%). HER-2 positive was revealed 10 cases, as 10.8% (95% CI 5.3% to 18.9%). Most cases were early to locally advance stage (89% vs 90%) Median overall survival was not reach in HER-2 positive group compared with 30.9 months in negative group. (hazard ratio 0.39; 95% CI 0.12 to 1.21; p 0.089).

Conclusion: Among patients with cholangiocarcinoma, 1 of 10 cases had HER-2 overexpression.

Keywords: Cholangiocarcinoma, prognostic factor, prognostic marker, HER-2 overexpression, overall survival, clinicopathological feature, biomarker