Big babies and infant leukemia: A role for insulin-like growth factor-1?

Several epidemiologic studies have demonstrated that high birthweight is associated with an increased risk of infant leukemia; however, the reason for this relationship is unclear. Biologic data demonstrate that birthweight is correlated positively with circulating levels of insulin-like growth factor-1 (IGF-1). IGF-1 is important in blood formation and regulation and has been shown to stimulate the growth of both myeloid and lymphoid cells in culture. Since infants who develop leukemia are likely to have had at least one transforming event occur in utero, we hypothesize that high levels of IGF-1 may both produce a larger baby and contribute to leukemogenesis.