We confirmed the microarray data by qRT-PCR (Fig. 1C), which revealed that MYCN overexpression in non-MYCN-amplified neuroblastoma SK-N-AS and SHEP1 cells significantly increased mRNA expression of genes encoding enzymes responsible for de novo synthesis of purine (PPAT, PFAS, PAICS, and ATIC, see also Fig. S1C) and pyrimidine (CAD, DHODH, and UMPS) nucleotides. This evidence concerns the gene PPAT and neuroblastoma.