Abstract: Background：The longterm survival of children with neuroblastoma (NB) associated with MYCN amplification is not promising, and few studies have been previously reported in China. Objective：To summarize the related factors of clinical characteristics, therapeutic effect and prognosis in NB children with MYCN amplification and to further improve the recognization of this group in NB. Design：Case series report. Methods：The clinical information of NB with MYCN amplification, diagnosed and treated from Feb 2007 to Jan 2020, were analyzed retrospectively, and the tumor location, size, metastasis, treatment, and risk factors affecting the prognosis were analyzed. Main outcome measures：Factors affecting the 3year survival of NB with MYCN amplification. Results：A total of 133 NB patients with MYCNAmp were included in this study, accounting for 12.02% of total NB patients in the same period in our center. The median age of onset was 35.7±9.8 months. There were 129 cases (97%) located in abdomen region and 4 cases (3%) in posterior mediastinal region. There were 81 cases (60.9%) with bone marrow metastasis, 80 cases (60.2%) with bone metastasis and 24 cases (18.1%) with central nerves system metastasis. Serum LDH ≥1 500 U·L-1was shown in 99 cases (74.4%). NES ≥100 ng·mL-1was found in 126 cases (94.7%). The largest tumor diameter (>10 cm) was in 89 cases (66.9%). The 3year OS and EFS were 19.7% and 19.0%. There were 78 cases of progressive recurrence, 8, 20, 46 and 4 cases of progressive recurrence happened at induction, consolidation, maintenance and withdrawal, respectively. Primary tumor, bone marrow, central nervous system and bone were the most common sites of progressive recurrence. The median time of first progression was 11.3 months. Bone marrow and bone metastasis, deletion of 1p36 were risk factors. Conclusion：A single center with large sample of MYCNAmp NB showed that the primary tumor was predominantly located in the retroperitoneal adrenal region, with a high rate of early distant metastasis, and more than 50% of the children developed tumor progression during maintenance therapy with 3year OS of 19.7%. These children urgently need targeted therapy and other new treatment to further improve the efficacy and the prognosis.

Key words: Neuroblastoma, MYCN amplification, Clinical characteristic, Prognosis