The enhanced sensitivity of EWS to NAMPT inhibition may be, in part, related to the known homologous repair deficiency that is a feature of EWS35, as DNA repair deficiencies have been linked to NAMPTi sensitivity in other solid tumor types23 and may increase dependence on the NAD-dependent PARPs59,60. This evidence concerns the gene EWSR1 and hyperinsulinemic hypoglycemia, familial, 4.