Neuroblastoma is the most common extracranial tumor in children, and is the most common tumor in infants and young children. Nearly half of all neuroblastomas occur in infants and children less than 2 years of age. Neuroblastoma accounts for approximately 6-10% of childhood tumors and 15% of childhood tumor mortality. For children under 4 years of age, the mortality rate is 10 per million population; for children 4-9 years of age, the mortality rate is 4 per million population. Neuroblastoma is a neuroendocrine tumor that can originate from any part of the nerve spine of the sympathetic nervous system. Its most common site of occurrence is the adrenal gland, but it can also occur in the nerve tissue of the neck, chest, abdomen, and pelvis. There are a few human tumors that are known to spontaneously regress from undifferentiated malignant tumors to completely benign ones. Neuroblastoma is one of them. The International Neuroblastoma Staging System (INSS) was established in 1986 and revised in 1988. The staging system is based on the primary organ of the tumor as well as metastasis. Stage 1: confined to the primary organ with no metastases; Stage 2A: sub-total resected unilateral tumor; clear absence of metastases in the ipsilateral as well as contralateral lymph nodes; Stage 2B: sub-total or total resected unilateral tumor; clear metastases in the ipsilateral lymph nodes and clear absence of metastases in the contralateral lymph nodes; Stage 3: tumor with trans-midline invasion with or without local lymph node metastases; or unilateral tumor with contralateral lymph node metastases. or a tumor growing across the midline with bilateral lymph node metastasis; Stage 4: tumor spreads to distant lymph nodes, bone marrow, liver, or other organs (other than those defined by Stage 4S). Stage 4S: children younger than 1 year of age; tumor confined to the primary organ; tumor spread confined to the liver, skin, or bone marrow (tumor cells less than 10% of the bone marrow nucleated cells). In 2005, several major global pediatric oncology research collaboratives began a retrospective comparison study of 8,800 neuroblastoma cases admitted between 1990 and 2002 in Europe, Japan, the United States, Canada, and Australia. Based on the results of this retrospective study, neuroblastoma was restaged according to the level of risk (INRGSS). This retrospective study found that children with neuroblastoma aged 12-18 months had a good prognosis; accordingly, the new classification system reclassified children aged 12-18 months without N-myc mutations from the previous high-risk group, to an intermediate risk group. The new risk classification system is as follows: Stage L1: limited lesions without imaging-determined risk factors; Stage L2: limited lesions with imaging-determined risk factors; Stage M: metastases; Stage MS: specific metastases (same as Stage 4S above); the new risk stratification system will be based on the new INRGSS staging system, age at presentation, tumor grade, N-myc amplification status, and N-myc amplification status. The new risk stratification system will classify neuroblastoma patients into: very low risk, low risk, intermediate risk and high risk groups based on the new INRGSS staging system, age of onset, tumor grade, N-myc amplification status, chromosome 11q unbalanced mutation and multinuclear factors.