These modifications of cellular iron metabolism seem to be related to the switch from MON to SPH rather than to malignant transformation per se, as in general iron proteins in normal immortalized cholangiocytes (H69 cell line) were not significantly different than in CCA MON, with the exception of FPN, which was less expressed in tumour cells, in line with previous results in other tumours11 (Supplementary Fig. 1). This evidence concerns the gene SLC40A1 and cholangiocarcinoma.