Pre-clinical models using human neuroblastoma samples and cell lines also show that MYCN amplification results in an increased expression of polyamine synthetic enzymes (ornithine decarboxylase antizyme inhibitor (OAZIN), spermidine synthase (SRM), spermine synthase (SMS), and adenosylmethionine decarboxylase 1 (AMD1)), and a decreased expression of catabolic enzymes (ornithine decarboxylase antizymes (OAZs), spermidine/spermine N1-acetyltransferase (SAT), and spermine oxidase SMOX) [9,20,21]. Here, SRM is linked to neuroblastoma.