The main results found: (1) Frequencies that are different from those expected in 19 SNPs; (2) 8 SNPs related with severe or life-threatening chemotherapy-associated toxicities; (3) SNPs influencing RIT in patients with high-risk NB and (4) SNPs in MTHFR, VDR and SOD2 genes identified as prognostic factors of OS or EFS, independently of MYCN amplification, underlying differential survival prediction possibilities independent of MYCN status. The gene discussed is MTHFR; the disease is neuroblastoma.