KRAS and neoplasm: We also identified an association with the number of ecDNA amplicons (log-odds = 0.46, p = 0.009, Supplementary Data 4) and increased KRAS expression (log odds 0.54, p = 5.47 × 10−4, logistic regression, p = 0.026, Wilcoxon rank sum test) in tumours with RS4, driven by tumours (15/19) with both ME insertions and KRAS amplification (Supplementary Fig. S2H, Supplementary Data 6).