At present, the diagnosis of CCA is mainly a comprehensive diagnosis combining medical history, imaging diagnosis and serological diagnosis; imaging diagnosis is mainly based on CT and MRI [34], serological diagnosis is mainly CA199 and carcinoembryonic antigen, and the sensitivity and specificity of CA199 for the diagnosis of CCA are 62 and 63% respectively [31, 35, 36]. The gene discussed is CEACAM5; the disease is cholangiocarcinoma.