This super-family of cystine-knot growth factors (CKGFs) includes five groups of factors in vertebrates : 1- TGFβs together with bone morphogenic factors (BMPs), growth and differentiation factors (GDFs) and activin-inhibin subunits, 2- nerve growth factors (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophic factors 3 and 4 (NTF3, NTF4), 3- platelet-derived growth factors (PDGF), 4- vascular endothelial growth factors (VEGF) and 5- the DAN (differential screening-selected gene aberrant in neuroblastoma) or CAN (Cerberus and Dan) family of BMP antagonists (68). Here, BDNF is linked to neuroblastoma.