Nevertheless, an increased risk ofMPNSTs may also exist for patients with mosaic type-2 NF1 microdeletions and plexiform neurofibromas, since most MPNSTsdevelop from pre-existing plexiform neurofibromas (Tucker et al. 2005) and the concomitant loss of NF1 and SUZ12 inplexiform neurofibroma cells harbouring the type-2 NF1 microdeletion increases the likelihood of malignanttransformation. This evidence concerns the gene NF1 and neurofibroma.