IFITM1 and malignant peripheral nerve sheath tumor: Endogenous IFITM1 levels were markedly lower in the two MPNST Schwann cell lines (sNF02.2 and sNF96.2) than those in the normal human Schwann cells (HSCs) (Figure 2A,B), demonstrating that IFITM1 was downregulated in both NF1-associated MPNST tissues and cells.