TTN-AS1 and cholangiocarcinoma: Furthermore, to confirm whether tumor cells indeed secrete exosomes rich in TTN-AS1 and whether they interact with stromal cells (including tumor cells) in the tumor microenvironment to promote cholangiocarcinoma metastasis, this research established a cholangiocarcinoma CTCs organoid model, overexpressed and silenced TTN-AS1 in cholangiocarcinoma cell lines and co-cultured the captured exosomes with cholangiocarcinoma cell lines with low TTN-AS1 expression.