PAEP and cholangiocarcinoma: We identified a 10-immune gene signature containing GUCA2A, CAMP, SERPINA3, PAEP, EREG, ANGPTL5, CCR7, ZAP70, CRP, and CXCL8 for CC OS prediction; CCR7, CAMP, ZAP70, SERPINA3, CXCL8, ANGPTL5, and CRP were retained in the CPS construction.