C1GALT1C1 and cholangiocarcinoma: Using a cut-off of 1.5-fold change, the expression levels of these four genes were down-regulated in CCA tissues compared to non-tumor tissues, evidenced by the percent of tumor cases showing high expression of C1GALT1–29% (26/90), COSMC–7% (6/90), B3GNT6–7% (15/90), and ST6GALNAC1–24% (22/90) (Figure 1A–D).