According to the results of the above analyses and the biological processes and pathways in which the marker genes were involved, the five AD sample modules were defined as the following molecular types: the MAPK type (495 samples), involving MAPK/PI3K-Akt/neurotrophin signaling; the synaptic type (475 samples), involving oxidative phosphorylation and synapses; the autophagy type (246 samples), involving Toll, nucleotide oligomerization domain (NOD), FoxO, PI3K-Akt, and autophagy; the FoxO type (90 samples); and the cell senescence type (47 samples), involving mTOR, FoxO, and cell senescence. This evidence concerns the gene BDNF and Alzheimer disease.