A significant proportion of t(12;21) leukemias also display loss of p16CDKN2A due to deletion mutations23, 43 and/or hypermethylation.44 Moreover, as RUNX1 SLGA also requires an intact p53 pathway24 it is conceivable that some t(12;21) leukemias acquire resistance to RUNX1 SLGA by mechanisms other than loss of p16CDKN2A. The gene discussed is TP53; the disease is leukemia.