The importance for NAD+ metabolism for therapy resistance is highlighted by the key roles of NAD+ metabolism for SAM-dependent methylation reactions and glioblastoma stem cell maintenance 194 as well as the dependence of self-renewal and radiation resistance of glioblastoma stem-like cells on nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting step in NAD+ synthesis 195. The gene discussed is NAMPT; the disease is glioblastoma.