In NB, TRK-A expression is associated with a positive outcome, since it mediates cell differentiation, growth regulation, and reduction of angiogenesis in response to NGF [223], while the TRK-B/BNDF pathway is frequently expressed in the most severe NB variants, in which it promotes cell survival and reduced sensitivity to cytotoxic anticancer agents [224]. This evidence concerns the gene NTRK1 and neuroblastoma.