A two-step differentiation into dopaminergic phenotype protocol with retinoic acid (RA) and further addition of brain-derived neurotrophic factor (BDNF) [23,24,25] was applied to stable neuroblastoma cell lines SH-SY5Y, which produce wild-type alpha-synuclein, and its mutant A53T, which is prone to accumulate thioflavin-S-positive aggregates [26]. Here, BDNF is linked to neuroblastoma.