MAPT and neuroblastoma: As(III) has been shown to activate the tau kinases, such as GSK3, ERK1/2, JNK, and CDK5 in human neuroblastoma SH-SY5Y cells (5–10 μM) [287, 288] and in the rat brain (intraperitoneal injections of 2.5 mg/kg body weight for 28 days) [287–290] and consequently leading to hyperphosphorylation of several tau residues, which are also hyperphosphorylated under pathological conditions.