In patients with NF1, CDKN2A is an early loss to promote atypical neurofibroma [41], while additional loss of tumor suppressors (e.g. TP53) and/or amplification of RTKs (e.g. MET or EGFR) is required for malignant transformation to MPNST [8]. This evidence concerns the gene CDKN2A and malignant peripheral nerve sheath tumor.