Knockdown of CTSX/Z expression or treatment with specific CTSX/Z inhibitors protected the pheochromocytoma cell line PC12 and neuroblastoma cell line SH-SY5Y from 6-hydroxydopamine (6-OHDA) toxicity and reduced apoptosis [63]. The gene discussed is CTSZ; the disease is hereditary pheochromocytoma-paraganglioma.