We picked up 26 DEGs identified in all CCA cases whose expression was confirmed to be related to CCA patient overall survival (OS) time in the TCGA database, and placed them in a plot to compare their expression levels in iCCA and eCCA respectively, it demonstrated that all those 26 DEGs in CCA were also dysregulated in iCCA, but none of them was found significantly dysregulated in eCCA, although some of the DEGs had opposite expression patterns in the two subtypes (Fig. 4e). The gene discussed is PRRT2; the disease is cholangiocarcinoma.