The role of N-Myc gene amplification in neuroblastoma childhood tumour – single-centre experience

Aim of the study
Neuroblastoma (NBL) is one of the most common extracranial tumours occurring in children with N-Myc gene amplification, acknowledged as a marker of poor prognosis. We assessed the frequency of N-Myc amplification and its impact on NBL markers and on the treatment outcome.

Material and methods
Among 160 children with NBL treated from 1991 to 2015 in one centre 140 patients had known N-Myc gene status, and they were enrolled in the study. The analysed group was divided into two subgroups: with and without N-Myc amplification (25 and 115 children, respectively). Association of N-Myc amplification with stage of the disease, levels of biochemical parameters, overall survival (OS) and failure-free survival (FFS) were analysed.

Results
The frequency of N-Myc amplification was 17.9%. Most children with N-Myc amplification (64%) were classified to stage 4 NBL. The levels of biochemical markers of NBL: ferritin, dopamine, NSE, and LDH were significantly higher in the group with N-Myc amplification, whereas the levels of VMA and HVA were lower. OS and FFS were significantly lower in children with N-Myc amplification in comparison to children from the control group (OS 53% vs. 76%, p = 0.03; FFS 50% vs. 72%, p = 0.03). The impact of N-Myc amplification on the treatment outcome was significant in patients with stage 4 NBL and children under one year of age.

Conclusions
N-Myc amplification is a crucial prognostic factor in neuroblastoma, which is associated with almost all features related with poor prognosis and a higher probability of unfavourable outcome.