PTGER1 and cholangiocarcinoma: Additionally, exosomal miR-183-5p also targets 5-hydroxy prostaglandin dehydrogenase (HPGD) in mast cells and CCA cells, leading to the upregulation of protumorigenic prostaglandin E2 (PGE2) and prostaglandin E receptor 1 (PTGER1) stimulation, in addition to inducing the release of VEGF from mast cells, promoting neoangiogenesis [73].