NRP1 and cholangiocarcinoma: A panel of CCA cell lines expressed different levels of NRP-1, where the order of cell lines with the highest to lowest expression was RBE, HCCC9810, QBC939, CC262, and FRH0201, but all expressed higher levels of NRP-1 than normal human biliary epithelial HIBEC cells (Supplementary Fig. S2A, B).