MYC and cancer: Using a non‐ecDNA gene AC019257.8 on chr8 as a karyotype reference, we co‐labelled the MYC and the AC019257.8 genes in the three cancer cell lines along with hESCs (Figure 3B, Supporting Information Figures S7C and S9A), and found a significantly higher number of MYC gene copies in COLO320DM cells compared to the PC3 cell lines, which was consistent with the results from the sequencing analysis (Figure 3B‐D).