MYCN and neuroblastoma: Low-risk neuroblastomas include stage L2 in children younger than 18 months of age with no 11q aberration; L2 in children older than 18 months of age with ganglioneuroblastoma, nodular, or differentiated neuroblastoma with no 11q aberration; and stage M in children younger than 18 months without MYCN amplification and hyperdiploidy.