FOXO3 and neuroblastoma: Besides, it has been reported that BDNF can stimulate the phosphorylation of FoxO3a by activation of the PI3K/AKT pathway in human neuroblastoma SH-SY5Y cells (Mai et al., 2002; Zhu et al., 2004) and a similar regulatory effect was found on primary cultured neurons in our previous studies (Zheng et al., 2002; Zheng and Quirion, 2004).