Altogether, these results are consistent with the poorer prognosis observed in del(11q) patients harboring TP53 alterations (Figure 1) and strongly reinforce the severe cell cycle defects in HG3‐del(11q) ATMMUTTP53MUT cells and therefore, the mutual exclusivity of biallelic ATM alterations and TP53 loss in CLL patients. The gene discussed is TP53; the disease is B-cell chronic lymphocytic leukemia.