We analysed pRPA2-S33 in a panel of cell lines, including three near-isogenic cell line pairs: COLO320DM/COLO320HSR (MYC-amplified colorectal cancer), GBM39ec/GBM39HSR (ref. 2) (EGFR-amplified glioblastoma) and PC3-DM/PC3-HSR (MYC-amplified prostate cancer) (Extended Data Fig. 1a–h), along with several other cell lines with or without ecDNA. The gene discussed is MYC; the disease is colorectal cancer.