COX6C and esophageal squamous cell carcinoma: Here, 8 ecDNA-related oncogenes were identified (SRSF1, COX6C, MYC, PVT1, BIRC2, BIRC3, MMP12, and YAP1), of which two (MYC and BIRC2) are candidate ecDNA-related oncogenes previously reported in studies of ESCC conducted by Cui et al. [32].