GH1 and neoplasm: In contrast, other players of the GH-IGF system, such as insulin-like growth factor binding protein 3 (IGFBP3) [46] and IGF-II receptors [47], inhibit mitogenesis, stimulate apoptosis and modulate IGF-I actions, thus acting as protective factors against tumor progression [30, 40–42, 46, 48] (Fig. 1).