Toward precision oncology: deciphering the circRNA-EMT axis in cancer and its therapeutic implications.

The epithelial-mesenchymal transition is a pivotal driver of cancer metastasis, the leading cause of mortality in solid tumours. Circular RNAs, a unique class of endogenous RNAs characterized by covalently closed loop structures and high stability, have emerged as key regulators in this process. Accumulating evidence reveals widespread dysregulation of circRNAs during EMT, where they function as critical modulators - either promoting or inhibiting the metastatic cascade. This review systematically elucidates the mechanisms by which circRNAs govern EMT, focusing on their interactions with classical signalling pathways (TGF-β, Wnt/β-catenin, and PI3K/AKT) and core EMT-transcription factors. Furthermore, we evaluate the dual promise of circRNAs as stable, disease-specific biomarkers for liquid biopsy and as novel therapeutic targets. Deciphering the complex circRNA-EMT regulatory network not only deepens our understanding of metastasis but also provides a rational framework for developing precision oncology strategies to intercept metastatic disease.