TP53 and neoplasm: In agreement, SP cells sorted from PDAC tissue had a much greater tumour-initiating potential compared with tumour-associated DP cells after orthotopic transplantation into immunocompromised mice (Extended Data Fig. 2e,f), and the few tumours that arose from DP cells had no GFP fluorescence (for example, representing cells that underwent a p53 LOH event) or focal p53 alteration events that maintained the GFP targeted locus (Extended Data Fig. 2g,h).