Patients and OS samples
A series of 20 surgically resected fresh human OS and corresponding adjacent nontumor tissue samples were collected at the First Affiliated Hospital of Zhengzhou University (Zhengzhou, China) and snap-frozen in liquid nitrogen from July 2018 to January 2019. Among them, 3 pairs were used for circRNA microarray analysis. No patients had received any preoperative treatment. Clinical data of patients included in this study are detailed in Supplementary Table 1. Samples used in this study were approved by the Committees for Ethical Review of the First Affiliated Hospital of Zhengzhou University.