CTLA4 and cholangiocarcinoma: In contrast, the expression levels of IL-6, CTLP4, Fas, NOS2, and EpCAM were significantly upregulated in iCCA patients compared to non-CCA subjects (p < 0.005 for IL-6, CTLA4, Fas, NOS2, and EpCAM; p < 0.01 for CTLA4).