CXXC5 has a high potential for application in the diagnosis of tumors, but there are also difficulties; as it was mentioned above, CXXC5 might play different roles at different stages of HCC progression, and its expression is altered accordingly, which may make the process from theory to realizing the value of CXXC5 in tumor diagnosis difficult. The gene discussed is CXXC5; the disease is hepatocellular carcinoma.