GPT and malignant glioma: Longer cell-free microDNA is enriched in preoperative samples compared to postoperative samples.21 Unlike other classes of eccDNA species, t-circles/c-circles are highly specific for ALT mechanisms and can be used as promising biomarkers for the diagnosis and management of ALT-positive tumors.283 Fogli et al. analyzed 63 malignant gliomas and identified that c-circles were significantly associated with low Ki-67 immunostaining.284