Since these tumours are all derived from an original Lgr5-Cre:Pik3caH1047R:Apc580D/580D tumour, where a H1047R mutation has been endogenously knocked-in to the Pik3ca allele, we used an allele-specific RT-PCR approach to confirm the presence of the knocked-in mutation across transplantation generations (Fig 2A). This evidence concerns the gene LGR5 and neoplasm.