This analysis revealed a 60-fold increase in leukaemia-initiating cells in the P53/R26-Zeb2tg/+- and P53/R26-Zeb2tg/tg-overexpressing tumours (0.33 leukaemic stem cell (LSC) per 103 tumour cells) compared with the P53/R26+/+ control tumours (0.50 LSC per 105 tumour cells) (Fig. 4a). The gene discussed is TP53; the disease is leukemia.