RAPGEF5 and intrahepatic cholangiocarcinoma: We used external data to validate our sequencing results and found that Circ-RAPGEF5 (CircBase ID: hsa_circ_0001681) was significantly upregulated as shown by our results and sequencing data from Chen et al. [21] (Fig. 1B), which suggested that Circ-RAPGEF5 was associated with the development of ICC.