PSEN1 and Alzheimer disease: Next, we investigated the role of Stat3 in the APPswe/PS1∆E9 (APP/PS1) mouse model of AD (Jankowsky et al, 2004), using a mouse line in which exons 12–14 of the Stat3 gene are flanked by loxP sites, enabling Cre‐mediated functional Stat3 deletion (Alonzi et al, 2001).