Applying immunohistochemical (IHC) staining to examine AKR1C1 expression in another 70 pairs of clinical tumor samples from ICC, ECC, hepatocellular carcinoma (HCC), gastric cancer (GC), pancreatic cancer (PC), colorectal cancer (CRC), esophageal cancer (EC) and the corresponding normal tissues, we also revealed that the ECC tissues had markedly stronger AKR1C1 immunostaining than other types of tumor samples, including ICC (Fig. 1G). Here, AKR1C1 is linked to intrahepatic cholangiocarcinoma.