In situ tau phosphorylation by GSK3β or pseudo-phosphorylation at GSK3β-phosphorylating sites increased the levels of tau in the culture medium as compared to wild type tau in Hela cells [13], HEK293 cells, and SH-SY5Y neuroblastoma cells [14], suggesting phosphorylation may be a major driving force for tau secretion to the extracellular matrix and subsequent spread of tau pathology [14]. The gene discussed is MAPT; the disease is neuroblastoma.