The capacity of each hub gene to distinguish AD from control samples according to expression level was then examined by ROC curve analysis, and the seven candidates with best discrimination performance (area under the ROC curve > 0.7), namely SP1, CASP3, MAPT, BCL2, FOXO1, ETS1, and MAPK9, were selected for further analyses (Fig. 13a). The gene discussed is MAPK9; the disease is Alzheimer disease.