Insulin-like growth factors and insulin: at the crossroad between tumor development and longevity.

Numerous lines of evidence indicate that insulin-like growth factor signaling plays an important role in the regulation of life span and tumor development. In the present paper, the role of individual components of insulin-like growth factor signaling in aging and tumor development has been extensively analyzed. The molecular mechanisms underlying aging and tumor development are frequently overlapping. Although the link between reduced insulin-like growth factor signaling and suppressed tumor growth and development is well established, it remains unclear whether extended life span results from direct suppression of insulin-like growth factor signaling or this effect is caused by indirect mechanisms such as improved insulin sensitivity.