In a study of a single patient with three different kinds of neurofibromas at the same time, a neurofibroma, a low-grade MPNST, and a high-grade MPNST, homozygous loss of the CDKN2A/p16 gene is detected in the malignant component, especially during the progression or occurrence of high-grade MPNST (42). This evidence concerns the gene CDKN2A and plexiform neurofibroma.