Furthermore, upon infection with pks+ WT E. coli, human colon organoids showed nuclear expression of the DSB repair proteins, phospho-checkpoint kinase 2 (Chk2) (Supplementary Fig. 2a), and p53-binding protein 1 (53BP1) (Supplementary Fig. 2b), indicating that DSB repair is activated in response to colibactin. This evidence concerns the gene CHEK2 and infection.