HEIH and cholangiocarcinoma: Mounting evidences have confirmed that HEIH as an oncogene, is abnormally expressed in numerous digestive system cancers, such as hepatocellular carcinoma (HCC) [21, 23–27], tongue squamous cell carcinoma(TSCC) [28], gastric cancer (GC) [29–31], esophageal cancer (EC) [32–34], colorectal cancer (CRC) [35], and cholangiocarcinoma [20].