Anti-apoptotic actions of insulin-like growth factors: lessons from development and implications in neoplastic cell transformation.

Insulin-like growth factor-I (IGF-I) is widely expressed during development, and is actively involved in the regulation of cell growth, proliferation, and differentiation. Underlying these activities is the capacity of IGF-I to promote survival in a variety of cell types, including those of the nervous system. However, in adult tissues deregulation of the IGF system can cause undesired cell survival and therefore excessive cell proliferation. Here, we review the contribution of IGF-I in developmental processes with a focus on the development of the inner ear, as well as pathological implications resulting from IGF-I deregulation during cancer.