They are primarily classified into four groups, as very low-, low-, intermediate-, and high-risk, based on their disease stage (according to the International Neuroblastoma Risk Group Staging System (INRGSS)), their age at the time of diagnosis, their histological type (maturing ganglioneuroma versus ganglioneuroblastoma, intermixed versus ganglioneuroblastoma, or nodular versus neuroblastoma), their grade, their MYCN gene status, their 11q chromosomal status, and their tumor cell ploidy [28,30]. Here, MYCN is linked to neuroblastoma.