High expression of YAP1 has frequently been reported in various cancers, such as cervical cancer (7), head and neck cancer (7), pancreatic cancer (28), breast cancer (29), intrahepatic cholangiocarcinoma (30), non-small cell lung cancer (31), and liposarcoma (32), and is correlated with poor prognosis, while the loss of YAP1 has potential as a clinical marker in small cell lung cancer (33). This evidence concerns the gene YAP1 and intrahepatic cholangiocarcinoma.