Abstract: Objective To investigate the regulatory role of hsa_circ_0073762 in papillary thyroid carcinoma (PTC) and to explore its underlying mechanisms. 
 Methods High-throughput sequencing was used to identify differentially expressed circular RNAs (circRNAs) in thyroid cancer and normal cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to validate the differential expression between cell lines, PTC, and adjacent tissues. Nucleic acid electrophoresis, sanger sequencing, and RNA enzyme digestion experiments were conducted to verify the circularity and stability of hsa_circ_0073762. Cell counting kit-8 (CCK-8), wound healing, clone formation, and migration assays were used to analyze the effects of hsa_circ_0073762 on PTC cell proliferation, migration, and invasion. A dual-luciferase reporter assay was used to validate the interaction between hsa_circ_0073762, miR-548c-3p, and the ENAH gene. 
 Results RT-qPCR validation of sequencing results showed that hsa_circ_0073762 was significantly upregulated in PTC cells (P＜0.001) and in cancer tissues (P＜0.05). Knockdown of hsa_circ_0073762 significantly inhibited the invasion, migration, and proliferation of PTC cells. Bioinformatics prediction and dual-luciferase reporter assays indicated that hsa_circ_0073762, miR-548c-3p, and ENAH formed a ceRNA network (P＜0.05). 
 Conclusion hsa_circ_0073762 has effects on the invasion, migration, and proliferation processes of PTC and may serve as a novel diagnostic biomarker and potential therapeutic target for PTC. 

Key words: thyroid cancer, papillary, RNA, circular, neoplasm invasiveness