Similarly, unique and autonomous activities of synthetic human Eb peptide(s) have been also reported, regulating growth and differentiation of human normal and malignant bronchial epithelial cells, as well as neuroblastoma cells, potentially through binding to putative membrane receptor sites distinct from those for IGF-I and insulin (Siegfried et al., 1992; Kuo and Chen, 2002, 2003). Here, IGF1 is linked to neuroblastoma.