MYCN and neuroblastoma: Furthermore, based on 11 baseline covariates: including age at high-risk diagnosis, sex, race, stage at HRNB diagnosis according to the 1993 International Neuroblastoma Staging System: pre-ASCT response, transplant type, time from ASCT to initiation of immunotherapy, duration of immunotherapy, overall response at the end of immunotherapy, time from diagnosis to the end of immunotherapy, and MYCN amplification status-propensity score matching was used to equilibrate DFMO and non-DFMO patients.