Hypermethylation of DcR1 (28.4%), but not death receptors (DR4 and DR5) and other TRAIL signalling-related genes (APAF1, CASP8 and DcR2) in our study indicates the potential use of recombinant TRAIL or TRAIL receptor agonistic monoclonal antibodies as selective anti-tumour therapy in CCA. Here, APAF1 is linked to cholangiocarcinoma.