MAN1A1 and cholangiocarcinoma: The significance of O-GlcNAcylation and MAN1A1 on the progression of CCA metastasis was confirmed by the facts that reduction of O-GlcNAcylation markedly suppressed the migratory and invasion abilities of both parental and highly metastatic CCA cells (Fig. 5d), whereas inhibition of MAN1A1 activity by kifunensine increased the observed functions (Fig. 5e).