IGF1 and neuroblastoma: Invasion into the BM could furthermore be mediated by insulin-like growth factor 1 (IGF-1) receptors on NB cells and the high expression of IGF ligands in the bone, allowing NB cells to bind to BM-endothelial cells and migrate through the endothelium toward the IGF-1 pool in the BM environment [115] (Fig. 1D).