Furthermore, Nampt not only promotes cancer cell proliferation but it can also exit cells to promote an immune suppressive microenvironment via various mechanisms [46,47,48,49], whereas inhibition of NAD metabolism was reported to improve the cytotoxicity of CD8+ effector T cells by regulating extracellular adenosine levels in the tumor microenvironment of gastric cancer [50]. Here, NAMPT is linked to cancer.