RNF138 and cholangiocarcinoma: In analyzing the data collected from The Cancer Genome Atlas (TCGA) database, we noticed that RNF138 is downregulated in different subsets of cancers, particularly in CRC, liver hepatocellular carcinoma, and thyroid carcinoma, to a less extent in cholangiocarcinoma and head and neck squamous cell carcinoma (Fig. 1a; Supplementary Table 1).