We also analyzed the mouse and human T-ALL and thymus control RNA-Seq data for the expression of NAMPT/Nampt and nicotinic acid phosphoribosyltransferase (NAPRT/Naprt), a rate-limiting enzyme similar to NAMPT which converts nicotinic acid to nicotinic acid mononucleotide, the first step in the alternative Preiss-Handler NAD synthesis pathway [6,8] (S1 Fig). Here, NAMPT is linked to acute lymphoblastic leukemia.