In order to examine the contribution of ATM/ATR activation to CX-5461-mediated G2 arrest in Eμ-Myc lymphoma cells, we combined CX-5461 with a dual CHK1/CHK2 inhibitor (CHK1/2i; AZD7762) and found that CX-5461/CHK1/2i combination abrogates the G2 arrest and renders Tp53−/− Eμ-Myc cell lines sensitive to cell death (Figure 5A and 5C). This evidence concerns the gene TP53 and lymphoma.