The biological functions of genes in the 17-gene classifier analysed by IPA were primarily involved in cell death (ACTN4, CNN2, EDNRB, KIT, NAMPT, PRAME, TRIB2 and VDAC1), cellular development (EDNRB, KIT, PRAME, TRIB2, TTC3, CNN2, ACTN4, VDAC1 and NAMPT), hair and skin development (EDNRB and KIT), cancer (EDNRB, KIT, TTC3, NAMPT, PRAME and RPS15) and neurological disease (EDNRB, KIT, NAMPT, RPL21 and TTC3). The gene discussed is NAMPT; the disease is nervous system disorder.