NRAS and neuroblastoma: Different studies have also reported somatic RAS-MAPK pathway gene alterations (mutation, amplification, or deletion) leading to the activation of this pathway in large cohorts of sporadic NB patients, with a frequency of around 4–10% [21, 24, 25]; the most frequently mutated genes were PTPN11 (2.9%), NRAS (0.8%), and NF1 [14, 24].