Likewise, TP53−/− rescued XRCC4 KO mice display a complete absence of mature lymphocyte development owing to their impaired V(D)J recombination, a trait accompanied by the onset of aggressive pro-B-cell lymphomas, revealing the role of XRCC4 as an important genome caretaker. Here, XRCC4 is linked to B-cell non-Hodgkin lymphoma.