Analysis of DNA repair foci with monoclonal γH2AX (γH2AXm) antibody in combination with polyclonal 53BP1 revealed similar DNA damage in UCB cells of healthy subjects and pediatric ALL patients while DSB levels were strikingly higher in UCB cells from child diagnosed with AML/DS (Figure 2B). The gene discussed is TP53BP1; the disease is acute myeloid leukemia.