DPP4 and cholangiocarcinoma: Our finding showed that abnormally expressed genes included CDKN1A, HSPA5, EMC2, SLC7A11, NFE2L2, MT1G, HSPB1, FANCD2, CISD1, FDFT1, SLC1A5, TFRC, RPL8, GLS2, DPP4, CS, CARS1, ATP5MC3, ALOX15, ACSL4, and ATL1 in CCA (Figure 2(a)).