The results showed that, compared with the control, TET1 expression was significantly elevated in cholangiocarcinomas (CHOLs), esophageal carcinomas (ESCAs), head and neck squamous cell carcinomas (HNSCs), liver hepatocellular carcinomas (LIHCs), lung adenocarcinomas (LUADs), lung squamous cell carcinomas (LUSCs), sarcomas (SARCs) and stomach adenocarcinomas (STADs), while it was significantly downregulated in breast invasive carcinomas (BRCAs), kidney chromophobes (KICHs), kidney renal papillary cell carcinomas (KIRPs), thyroid carcinomas (THCAs) and thymomas (THYMs) (Fig. 1A). The gene discussed is TET1; the disease is cholangiocarcinoma.