Insulin-like growth factor-II (IGF-II) is a key regulator of cell growth, survival, migration and differentiation. Its pivotal role in these processes requires tight regulation of both expression and activity. The type 1 IGF receptor tyrosine kinase (IGF-1R) mediates IGF-II actions, and a family of six high affinity IGF binding proteins (IGFBPs) regulates IGF-II circulating half-life and its availability to bind IGF-1R.