TWIST1 and malignant peripheral nerve sheath tumor: EMT-associated transcription factors such as SNAIL (SNAI1), SLUG (SNAI2), Twist Family BHLH Transcription Factor (TWIST)-1, Zinc Finger E-Box Binding Homeobox (ZEB) have been shown to be upregulated in malignant peripheral nerve sheath tumor (MPNST) deficient for neurofibromin [20, 21].