KLF4 and cholangiocarcinoma: Same KLF4 expression patterns were found in the TCGA database (https://tcga-data.nci.nih.gov/tcga/), with lower expression observed in many kinds of tumors including lung adenocarcinoma (LUAD), bladder urothelial carcinoma (BLCA), and cholangiocarcinoma (CHOL) (opposing to matched para-tumorous tissues) (Figure 1D).