Neural stem cells have been identified in the central nervous system (CNS) of several different species, including humans. Their physiological function consists in the replacement of physiologically lost neurons within restricted CNS areas such as the olfactory bulbs and the hippocampus. These cells are thought to be etiologically involved in the pathogenesis of several genetic diseases involving the CNS. At the same time, they are considered the cell substrate, which, upon mutation, can transform and give rise to cerebral tumors. The research activity of our group is currently focused on the study of the basic biology of neural stem cells, in relation with the pathogenesis of tuberous sclerosis complex, a genetic disease severely affecting the CNS, and the development of highly malignant brain tumors such as glioblastoma multiforme and medulloblastoma. To this end, neural stem cells of different origin are compared, both from a functional and molecular standpoint, to cancer stem cells and/or to neural stem cells bearing specific mutations, by exploiting in vitro and in vivo models joined with state-of-the-art molecular technologies.