Transplantation of Pot1b∆/∆; p53−/− B cells expressing a dominant negative form of Caspase 3 promotes lymphomagenesis in SCID mice, further supporting the hypothesis that dysfunctional telomeres induced by Pot1b loss activates p53‐independent apoptosis to suppress the formation of B‐cell lymphomas. Here, TP53 is linked to B-cell non-Hodgkin lymphoma.