Tucidinostat Plus Etoposide in the Treatment of Neuroblastoma in Childhood.

Inclusion Criteria: 1. Age 3\~18 years old; 2. Patients must have a life expectancy of at least 6 weeks and a Lansky (≤16 years) or Karnofsky (\>16 years) score of at least 50; 3. Histologically confirmed neuroblastoma and/or demonstration of tumor cells in the bone marrow with increased urinary catecholamines; 4. Patients must have a history of high-risk neuroblastoma, at least one measurable lesions according to the RECIST 1.1; 5. Patients who have progressed, recurrent or refractory disease after first-line treatment; 6. The residual disease biopsy must be done, if patiens who have persistent disease obtain incomplete response after first line treatment; 7. Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to study registration； 8. Patients have not received enzyme-induced anticonvulsant therapy; 9. Patients have not received valproic acid within 30 days before admission; 10. ANC ≥ 1.5×10\^9/L, PLT ≥75×10\^9/L;TBIL≤1.5ULN, ALT and AST≤3×ULN（ALT and AST≤5×ULN if liver metastasis）;BUN and Cr≤1.5×ULN 9）LVEF ≥ 50% and QTc≤470 ms. 11. Patients' guardians must be willing and able to understand and comply with the protocol for the duration of the study. Exclusion Criteria: 1. Patients with severe cardiovascular disease; 2. Patients who have previously received organ transplants; 3. Inability to swallow pills; 4. Female patients during pregnancy and lactation, fertile women with positive baseline pregnancy tests or women of childbearing age who are unwilling to take effective contraceptive measures throughout the trial; 5. Active HIV, hepatitis B or hepatitis C; 6. Researchers believe that patients are unsuitable for any other situation in this study.