TrkA and TrkC high expression are favorable prognostic markers in neuroblastoma, in association with a differentiated phenotype and absence of MYCN amplification, whereas high TrkB expression associates with aggressive neuroblastomas and chemotherapy resistance (Nakagawara et al., 1993; Nakagawara et al., 1994; Yamashiro et al., 1997; Ho et al., 2002; Jaboin et al., 2002). This evidence concerns the gene MYCN and neuroblastoma.