Overview

• An international team in Cancer Discovery reports that ecDNA can appear at the very start of glioblastoma development, sometimes preceding detectable tumor formation.
• Team eDyNAmiC analyzed 94 treatment‑naive human tumors using multi‑site sampling, imaging, and computational modeling to reconstruct ecDNA evolution in space and time.
• Most ecDNA rings carried EGFR, which frequently accumulated early and expanded before clonal sweeps, shaping aggressive tumor behavior.
• Variant EGFR ecDNAs, most often EGFRvIII, arose from preexisting EGFR ecDNA and were associated with increased aggressiveness and treatment resistance.
• Researchers propose liquid‑biopsy assays to detect early EGFR ecDNA and plan follow‑up studies to track how therapies influence ecDNA dynamics, with in vivo mouse evidence supporting pretumor ecDNA accumulation.