Aβ42 peptides enhanced the transcription of p53, which is responsible for controlling cell apoptosis.412,413 In addition, Aβ42 induced oxidative stress and decreased the expression of X-linked inhibitor of apoptosis (XIAP), which directly inhibited key proteases of the apoptosis pathway including caspase 3, 7 and 9.414,415 Bcl-2, another key anti-apoptotic protein, was also shown to be blocked by Aβ42 peptides.416 In contrast, Aβ42 stimulated the expression of Bax, which induced cell apoptosis and was commonly observed in many cancers.416,417. The gene discussed is XIAP; the disease is cancer.