17 APA patients (38.6%), 9 PPA patients (45.0%) and 7 other subtypes of patients (58.3%) were confirmed as positive, but only 3 SPA patients (12.0%) was were confirmed as positive (P = 0.021; Figure 4), suggesting that immunostaining of Notch-1 in LAD tissues could be helpful for differentiating SPA from other histological subtypes. This evidence concerns the gene NOTCH1 and primary progressive aphasia.