MYCN and neuroblastoma: Patients with NB are divided into different risk-assessment groups, and The International Neuroblastoma Risk Group (INRG) applies a classification system based on key NB criteria, such as age, stage, tumor histology, MYCN amplification (MNA), 11q deletion and ploidy to define very low-, low-, intermediate-, and high-risk (HR) groups according to 5-year event-free survival (EFS) [4].