Among the ecDNA-amplified genes occurring in two or more samples in this cohort were known or suspected medulloblastoma oncogenes MYC, MYCN, MYCL, TERT, GLI2, CCND2 (ref. 25), PPM1D (WIP1) (ref. 26) and ACVR2B (ref. 27); genes encoding DNA repair machinery (RAD51AP1 and RAD21); and genes encoding TP53 pathway inhibitors (PPM1D28 and CDK6 (ref. 29)) (Fig. 1b). The gene discussed is TP53; the disease is medulloblastoma.