TP53 and lymphoma: We observed that while various tissue sections from normal wild type age matched litter mate mice exhibited very low levels of Separase protein (seen only in mitotic cells, wild type lung and liver, Figure 5A, bottom two panels), the ESPL1+/hyp, p53−/− mice showed a striking increase in interphase nuclear Separase levels in the lymphoma invaded tissue (Figure 5A, top panel).