However, when we repeated this experiment using primary cells derived from a r/r B-ALL patient expressing mutant p53, addition of UCN-01 to IO doubled the apoptotic rate compared to IO alone (from 53.9 to 96.84%) employing an IO dose 30-fold lower than the mean IC50 calculated for r/r B-ALL patients (Figures 7C,D). Here, TP53 is linked to acute lymphoblastic leukemia.