To investigate DNA damage, we probed human control and AD cortical brain with P-p53 (Ser15) and phosphorylated (Ser139) histone H2AX (P-H2AX) also known as γH2AX, a marker for DNA double-strand breaks (DSBs) [75, 97] (Fig. 2f). The gene discussed is H2AX; the disease is Alzheimer disease.