Sex differences in opisthorchiosis and the development of cholangiocarcinoma in Syrian hamster model.

Worldwide, the highest incidence of cholangiocarcinoma (CCA) is found in northeast Thailand, the endemic area of Opisthorchis viverrini infection. Cumulated clinical data revealed that the majority of CCA patients are men. However, many other types of cancers are more commonly found in women. In this study, we investigated the sex differences in the development of CCA, induced by O. viverrini infection and N-nitrosodimethylamine administration, in Syrian hamsters. Histopathology, liver function tests, and fecal egg counts were analyzed. The results showed that there are no sex differences in hamsters responses to O. viverrini infection and no prevalence of CCA development. Even though serum ALT level in O. viverrini-infected or CCA hamsters was significantly increased in female compared to male (p < 0.05) and uninfected control (p < 0.05), our results may imply that the higher prevalence of opisthorchiasis and CCA in men than in women in northeast Thailand may depend on behaviors of an individual exposed to risk factors rather than gender difference.