Oxidative stress is detected even at the earliest stages of AD, before Aβ accumulation, and it has been demonstrated that ROS production favors Aβ deposition and Tau phosphorylation through the Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) (JNK/p38 MAPK) signaling cascade [215]. This evidence concerns the gene MAPK8 and Alzheimer disease.