Among 46 human HCC and 5 cholangiocellular carcinoma sample sections examined, all grade 1 HCC areas of well-differentiated cells (Figure 6A) and all hepatocytes in tumor-adjacent (≥ 1.5 cm from the edge of the tumor foci) (Figure 6B, D, F) and phenotypically normal liver areas (as represented in Figure 6H from patients having different grades of HCC) from grade 1–3 HCC patients, exhibited a high level of staining for FGF21 (as represented by the green arrowheads). This evidence concerns the gene FGF21 and cholangiocarcinoma.