The tumours arise from neural crest-derived cells, either sporadically or in association with the hereditary syndrome neurofibromatosis type 1 (NF1), which is caused by a germline mutation in the tumour suppressor gene NF1. The incidence of MPNST is high among patients with NF1,2 and approximately half of the cancers occur in this hereditary setting.1 This evidence concerns the gene NF1 and neoplasm.