2.1. Patients
The plasma and tumor tissue samples of NB patients and corresponding clinical data were collected from Children’s Hospital Affiliated to Zhengzhou University. Inclusion criteria are as follows: (1) histologically confirmed NB diagnosis; (2) assessment of MNA status by FISH method; (3) availability of tumor and plasma samples; (4) written informed consent from patients or their parents at the time of sample collection. The research proposal was approved by the ethics review committee of Children’s Hospital Affiliated to Zhengzhou University.