MYCN and metastatic neoplasm: The groups included patients with metastatic (INSS stage 4) disease and age > 18 months, patients with age < 18 months, metastatic disease (INSS stage 4) and not amplified MYCN, and patients with localized (INSS stage 1, 2) or metastatic (INSS stage 4s) tumors with not amplified MYCN, and patients with age > 18 months, stage 3 and not amplified MYCN that are classified as high, intermediate, and low risk according to INRG schema [1,2,30].