Moreover, DCDC2 mRNA levels of the ICC and ECC tissues from Fudan cohort-I and TCGA-CHOL cohort were analyzed in detail, and it was in ICC tissues that DCDC2 mRNA levels were specifically upregulated (Fig. 1E and Supplementary Fig. 1D). The gene discussed is DCDC2; the disease is intrahepatic cholangiocarcinoma.