are important factors both in aging and in the development of cancer. Insulin/insulin-like
growth factor 1 (IGF-1) signaling molecules that have been linked to longevity include DAF-2
and InR and their homologues in mammals, and inactivation of the corresponding genes is
followed by increased life span in nematodes, fruit flies and mice. It is possible that the life-
prolonging effects of calorie restriction are due to decreasing IGF-1 levels. A search of …