This suggests that EMT induced by NETs formation may play a pivotal role in the PPA occurrence and development.[12] As a principal fibrotic mediator of EMT, transforming growth factor‐β1 (TGF‐β1) also plays an indispensable role in PMC‐induced fibrosis and PPA formation.[15] It can bind with specific receptors on the cell membrane, and then the receptors are activated and phosphorylated by the downstream Smad 2 and/or Smad3, which then form heterotrimeric complexes with Smad4. Here, SMAD4 is linked to primary progressive aphasia.