Some important questions remain to be elucidated: (1) whether pathological tau secreted via ectosomes can be internalized and induce tau seeding in neurons; (2) whether ectosomal tau can be detectable in biological fluids (ISF, CSF, or blood) of tauopathy patients; (3) what are the molecular pathway(s) responsible for ectosomal tau release. This evidence concerns the gene MAPT and tauopathy.