Given that CTs can cross the blood–brain barrier via organic anion transporting polypeptides (OATPs), we investigated the effect of acute exposure to low concentrations (10 nM and 50 nM) of CTs, namely microcystin-LR (MC-LR), nodularin (NOD), cylindrospermopsin (CYN), and known neurotoxin β-N-methylamino-l-alanine (BMAA) in neuroblastoma SH-SY5Y cells. The gene discussed is TTR; the disease is neuroblastoma.