Despite the similar NAPRT-negative cancer cell-targeting effects of two different NAMPT inhibitors, FK866 and KPT-9274, A4276 was noted for its wider therapeutic window, considering the discrepancy between the responses of NAPRT-positive and negative cancer cell lines (Figure 1C-D and, Figure S1B-C), along with its innocuousness in NAPRT-positive normal cell lines (Figure 3E and Figure S4). This evidence concerns the gene NAMPT and cancer.