Abstract
Cadherin 17 (CDH17) is a cell adhesion glycoprotein essential for epithelial integrity. It is frequently overexpressed in various cancers, where it is associated with aggressive behaviour. While evidence indicates that CDH17 functions as an upstream regulator of Wnt/β-catenin signalling, findings are inconsistent across tumour types, limiting the assessment of CDH17 as a biomarker or therapeutic target for Wnt pathway in cancer. In this study, we systematically review and meta-analyse the relationship between CDH17 and Wnt/β-catenin signalling in human cancers and evaluate whether CDH17 modulation affects tumour behaviour through Wnt-related mechanisms. Our search of Medline, Web of Science and Scopus identified five studies examining CDH17 expression in the Wnt/β-catenin pathway in vitro and in vivo. All five studies identified CDH17 as a key driver of canonical Wnt signalling, directly influencing cancer progression in hepatocellular carcinoma (HCC), gastric cancer (GC), and colorectal cancer (CRC). Meta-analysis (MA) showed that CDH17 inhibition consistently reduced Wnt/β-catenin downstream T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) transcriptional activity (MD = -1.32, 95% CI: -1.64 to -0.99, p < 0.00001). Narrative synthesis found that CDH17 suppression decreased total and nuclear β-catenin, phosphorylated glycogen synthase kinase-3 beta (GSK-3β), and cyclin D1 while increasing tumour suppressors, retinoblastoma (Rb) and p53/p21. These changes were associated with reduced proliferation, colony formation, migration, invasion and cell cycle arrest. In vivo, CDH17 suppression resulted in 80-95% tumour growth suppression (Mean Difference (MD) = -96.67, 95% CI: [-144.35, -48.98], p < 0.0001), with immunohistochemistry confirming cytoplasmic β-catenin sequestration and lower cyclin D1 levels. Collectively, these findings show CDH17 as a critical upstream effector sustaining Wnt/β-catenin signalling, cancer progression, tumour proliferation, stem cell properties, and metastasis, and support CDH17 inhibition as a promising therapeutic target across multiple cancer types.