Considering the fact that human neuroblastoma SH-SY5Y cells (a widely used cellular model to study PD) are able to express a lot of features characteristic for dopaminergic neurons, including dopamine-β-hydroxylase and tyrosine hydroxylase activities (Kovalevich et al., 2021), we chose SH-SY5Y cells as a positive control to test the toxicity of MPP+. The gene discussed is TH; the disease is Parkinson disease.