BAIAP2 and neuroblastoma: In fact, these ideas were further supported by the findings that overexpression of IRSp53 can increase spine density in cultured hippocampal neurons [76] and induce filopodium formation and neurite outgrowth in N1E-115 neuroblastoma cells [77,142], whereas RNA interference knockdown of IRSp53 protein decreases spine density and alters spine morphogenesis [76].