RASA2 and neurofibromatosis type 1: Malignant transformation can occur either sporadically or in patients with the tumor-predisposing genetic syndrome Neurofibromatosis type 1 (NF1), caused by loss of function mutations in the tumor suppressor NF1 gene encoding the Ras-GTPase activating protein (Ras-GAP) neurofibromin [1].