TTN and cholangiocarcinoma: Using the expression of TTN-AS1 in healthy individuals’ serum exosomes as a control, the ROC curve of TTN-AS1 in cholangiocarcinoma patients’ serum exosomes was plotted, resulting in an AUC of 0.889 with a 95% confidence interval of 0.811–0.966, a sensitivity of 84.4%, and a specificity of 84.4% (Fig. 5H).