Cholangiocarcinomas are biliary tree neoplasms of cholangiocyte origin. Several clinical risk factors are associated with cholangiocarcinogenesis. During the last decade, there has been an increasing interest in the causative molecular mechanisms of cholangiocarcinoma because of its poor prognosis and the lack of effective therapies. A better understanding of cholangiocarcinoma tumor initiation, promotion, and progression, as well as neurotransmitter, neuroendocrine, and endocrine growth effects, may elucidate molecular targets for diagnostic and therapeutic purposes.