Expression profiling and bioinformatics analysis of serum exosomal circular RNAs in lymph node metastasis of papillary thyroid carcinoma

Most papillary thyroid carcinoma (PTC) patients have a good prognosis. However, lymph node metastasis (LNM), the most common manifestation of disease progression, is frequently associated with a poor prognosis. Nevertheless, few studies have focused on the underlying mechanisms of LNM. In the current study, we aimed to investigate the potential role of exosomal circRNAs that contribute to LNM in PTC. We identified 9 000 differentially expressed exosomal circRNAs in PTC patients with LNM, including 684 upregulated and 2 193 downregulated circRNAs. Functional enrichment analysis revealed that these differentially expressed circRNAs were primarily involved in a variety of molecular and signaling pathways correlated with PTC progression and LNM. Through bioinformatics analysis, we identified 14 circRNA-miRNA-mRNA networks related to LNMassociated signaling pathways in PTC. Moreover, both circTACC2-miR-7-EGFR and circBIRC6-miR-24-3p-BCL2L11 axes were verified for their potential involvement in PTC with LNM. Additionally, we identified four upregulated circRNA-related hub genes and eight hub genes correlated with downregulated circRNAs, some of which were validated as being potentially involved in LNM in PTC. Collectively, our findings provide a novel framework for an in-depth investigation of the function of dysregulated exosomal circRNAs and their potential as biomarkers in PTC patients with LNM.