Various factors are used to stratify patient risk such as: 1) age at diagnosis; 2) stage defining the extent of the disease by the International Neuroblastoma Staging System (INSS) (stage 1, 2A, 2B, 3, 4, or 4S); 3) tumor histology using the International Neuroblastoma Pathology Classification criteria; 4) MYCN status; and 5) DNA index or tumor cell ploidy 4, 5. This evidence concerns the gene MYCN and neuroblastoma.