CDK5 and neuroblastoma: The strategy for examining the regulation and function of AAH and related genes evolved from a series of independent experiments demonstrating that: 1) IGF-1 promotes migration of immature neuroblastic and neuroblastoma cells [20-22]; 2) IGF-I can stimulate AAH expression [17,23]; and 3) cyclin dependent kinase-5 (Cdk-5) is an important regulator of neuronal migration in the developing central nervous system (CNS) [24-28].