Several RNA species were differentially present in urine-derived EVs in CCA patients compared to healthy individuals, such as the mRNAs MAP6 domain containing 1 (MAP6D1) and Ras-related GTP-binding D (RRAGD) and the long non-coding RNAs (lncRNAs) HLA complex group 4 (HCG4) and the lncRNA LOC100134868. The gene discussed is HCG4; the disease is cholangiocarcinoma.