ecDNAs were significantly enriched for oncogenes as compared to non-oncogenes (Extended Data Fig. 9b; Fisher’s exact test, P = 8.9 × 10−4, one-sided)—including oncogenes that are known to drive EAC, such as ERBB2, KRAS and MYC, which were recurrently detected on ecDNAs found in Barrett’s oesophagus and EAC across multiple cohorts (Fig. 4f,g and Supplementary Table 6). Here, KRAS is linked to Barrett esophagus.