In addition to deregulated expression of N-MYC due to gene amplification or dysregulation at mRNA and protein levels, a recurrent somatic mutation, proline 44 to leucine (P44L) (Figure 1A), is identified in various tumors (141), including, glioma (142), neoplastic cysts of the pancreas (143), medulloblastoma (144), neuroblastoma (145), Wilms tumor (67), skin basal cell carcinoma (146), T-lineage acute lymphoblastic leukemia (147), NUT midline carcinoma (148), Ovarian mesonephric-like adenocarcinoma (149). This evidence concerns the gene MYCN and medulloblastoma.