In LS-1034 and SW837, which showed more cell death with combined TOP1i and CHEK1 inhibition than SNU-81 in vitro (Fig. 4e), the effect of the combination therapy on end-of-treatment tumour volumes and on tumour growth inhibition over time was more pronounced than that for irinotecan alone (Welch’s t-test, P < 0.05) (Fig. 4g, Extended Data Fig. 8a). This evidence concerns the gene CHEK1 and neoplasm.