In cancer cells, NAD is mainly synthesized from nicotinamide via NAD salvage.[38] NAMPT is the rate‐limiting enzyme in the NAD salvage and is therefore a popular therapeutic target.[39] Expectedly, NAMPT inhibition results in a metabolic pattern, which is characterized by strong depletion of NAD and NADP but also of their cleavage products ADP‐ribose (ADPR) and ADP‐ribose 2′‐phosphate (ADPPR) (Figure 2). Here, NAMPT is linked to cancer.