KRT19 and cholangiocarcinoma: Through class comparisons in Cohorts 1–3, Laminin Subunit Gamma 2 (LAMC2) and KRT19 were identified as key candidates upon the stringent criteria, i.e., 8 times higher expression level in CCA tumor versus non‐tumor liver tissues (p < 0.001) and normal bile duct cells (p < 0.001), but no difference in HCC tumor versus non‐tumor liver tissues (p > 0.05) (Figure 1A,B).