AIM: To explore the role of interferon-induced protein with tetratricopeptide repeats 1 (IFIT1) in the development of cholangiocarcinoma (CCA). METHODS: RT-qPCR and Western blot were used to evaluate the expression of IFIT1 at mRNA and protein levels, respectively, in various human cell lines, including a normal bile duct cell line and six distinct CCA cell lines. The level and prognostic value of IFIT1 were validated in human CCA and para-tumor tissues, accompanied by a comprehensive analysis of the pathological parameters and clinical significance of IFIT1. To ascertain the role of IFIT1 in CCA progression, we conducted CCK-8, colony formation and Transwell assays to investigate the impact of IFIT1 knockdown on the proliferation, migration and invasion of CCA cells in vitro. For in vivo experimentation, we chose HuCCT1, a human CCA cell line with a high metastatic potential, to create subcutaneous xenograft and lung metastatic tumor models in nude mice. We observed the effect of IFIT1 on the growth and metastasis of orthotopic CCA xenograft with IFIT1 knockdown. Gene set enrichment analysis (GSEA) of public databases was performed to reveal the underlying mechanism regulated by IFIT1 in CCA progression, which was subsequently confirmed by functional studies in vitro. RESULTS: Compared with normal bile duct cells, IFIT1 was significantly up-regulated in human CCA cell lines, particularly in HuCCT1 and QBC939 cells with higher metastatic potential, as well as in CCA tissues compared with para-tumor tissues( P<0. 01). Moreover, in a separate cohort of 44 CCA patients, up-regulated IFIT1 was positively correlated with tumor malignancy features such as tumor size, lymph node metastasis, TNM staging, and poor prognosis (P< 0. 01). These results suggest that IFIT1 plays a crucial role in CCA malignancy. Functional analysis revealed that knockdown of IFIT1 effectively inhibited the growth and metastasis of CCA cells in vitro and in vivo (P<0. 01). Bioinformatic screening analysis indicated that the Wnt/β-catenin pathway, an epithelial-mesenchymal transition (EMT)-associated signal pathway, was significantly enriched in CCA patients with up-regulated IFIT1. Consistently, knockdown of IFIT1 in CCA cells markedly inhibited Wnt/β-catenin activation, resulting in decreased EMT-related markers such as vimentin and Snail. CONCLUSION: IFIT1 promotes CCA progression through the enhancement of Wnt/β-catenin-mediated EMT, suggesting that IFIT1 may serve as an independent prognostic biomarker for CCA patients. [ABSTRACT FROM AUTHOR]