Cholangiocarcinoma (CCA) is a highly malignant biliary tract cancer with currently suboptimal diagnostic and prognostic approaches. We present a novel system to monitor CCA using exosomal circular RNA (circRNA) via serum and biliary liquid biopsies. A pilot cohort consisting of patients with CCA-induced biliary obstruction (CCA-BO, n = 5) and benign biliary obstruction (BBO, n = 5) was used to identify CCA-derived exosomal circRNAs through microarray analysis. This was followed by a discovery cohort (n = 20) to further reveal a CCA-specific circRNA complex (hsa-circ-0000367, hsa-circ-0021647, and hsa-circ-0000288) in both bile and serum exosomes. In vitro and in vivo studies revealed the three circRNAs as promoters of CCA invasiveness. Diagnostic and prognostic models were established and verified by two independent cohorts (training cohort, n = 184; validation cohort, n = 105). An interpreter-free diagnostic model disclosed the diagnostic power of biliary exosomal circRNA signature (Bile-DS, AUROC = 0.947, RR = 6.05) and serum exosomal circRNA signature (Serum-DS, AUROC = 0.861, RR = 4.04) compared with conventional CA19-9 (AUROC = 0.759, RR = 2.08). A prognostic model of CCA undergoing curative-intent surgery was established by calculating early recurrence score, verified with bile samples (Bile-ERS, C-index=0.783) and serum samples (Serum-ERS, C-index = 0.782). These models, combined with other prognostic factors revealed by COX-PH model, enabled the establishment of nomograms for recurrence monitoring of CCA. Our study demonstrates that the exosomal triple-circRNA panel identified in both bile and serum samples serves as a novel diagnostic and prognostic tool for the clinical management of CCA.

胆管癌（CCA）是一种高度恶性的胆道癌症，目前的诊断和预后方法并不理想。我们提出了一种利用外泌体环状 RNA (circRNA) 通过血清和胆汁液体活检监测 CCA 的新系统。由 CCA 诱导的胆道梗阻 (CCA-BO, n  = 5) 和良性胆道梗阻 (BBO, n = 5)患者组成的试点队列 用于通过微阵列分析鉴定 CCA 衍生的外泌体 circRNA。随后，一个发现队列 ( n  = 20) 进一步揭示了胆汁和血清外泌体中的 CCA 特异性 circRNA 复合物（hsa-circ-0000367、hsa-circ-0021647 和 hsa-circ-0000288）。体外和体内研究揭示了这三种 circRNA 作为 CCA 侵袭性的促进剂。诊断和预后模型由两个独立队列建立和验证（训练队列，n  = 184；验证队列，n  = 105）。与传统 CA19 相比，无解释器诊断模型揭示了胆汁外泌体 circRNA 特征（Bile-DS，AUROC = 0.947，RR = 6.05）和血清外泌体 circRNA 特征（Serum-DS，AUROC = 0.861，RR = 4.04）的诊断能力-9（AUROC = 0.759，RR = 2.08）。通过计算早期复发评分建立了接受根治性手术的CCA预后模型，并用胆汁样本（Bile-ERS，C-index = 0.783）和血清样本（Serum-ERS，C-index = 0.782）进行验证。这些模型与 COX-PH 模型揭示的其他预后因素相结合，能够建立用于 CCA 复发监测的列线图。我们的研究表明，在胆汁和血清样本中鉴定的外泌体三重环状RNA组可作为CCA临床管理的新型诊断和预后工具。