Regarding serum, comparison of CCA patients’ and healthy individuals’ EV-derived RNA revealed the RNA candidate mRNAs ring finger and FYVE-like domain containing E3 ubiquitin protein ligase (RFFL), olfactory receptor family 4 subfamily F member 3 (OR4F3), and the family with sequence similarity 107 member B (FAM107B) as well as ncRNAs PMS1 homolog 2 mismatch repair system component pseudogene 4 (PMS2L4), miR-604, and SNORA58. The gene discussed is OR4F3; the disease is cholangiocarcinoma.