HIF1A and hilar cholangiocarcinoma: This study therefore investigated the therapeutic potential of the HIF-1 dimerization inhibitor acriflavine (ACF) in an in vitro PDT setting for the treatment of human perihilar cholangiocarcinoma (SK-ChA-1) cells [34], i.e., a cell line derived from a type of cancer that is recalcitrant to different types of treatment.