The molecular mechanism of O-GlcNAc-mediated progression of CCA was shown to proceed via a series of signaling events, involving the activation of Akt/Erk (i), an increase in FOXO3 phosphorylation (ii), which results in the reduction of MAN1A1 expression (iii) and thus the accumulation of Hex9HexNAc2 N-glycans (iv). The gene discussed is MAN1A1; the disease is cholangiocarcinoma.