MAPT and neuroblastoma: Our previous study showed that conditional transfectants expressing multiple tau isoforms (0N4R, 1N3R, and 1N4R) of wild-type human tau in M17D human neuroblastoma recapitulated the key characters of neurofibrillary degeneration (e.g., progressive tau aggregation, phosphorylation, truncation, tau fibril formation, and ubiquitination) [9].