APEX1 and malignant peripheral nerve sheath tumor: Ref-1 is a multifunctional protein in redox regulation of various transcription factors, including HIF1-α, NFκB and STAT3.16 It is also known to act as an apurinic/apyrimidinic endonuclease repairing DNA damage as well as reported functions in RNA processing, and interactions with nucleophosmin 1 (NPM1).16 We characterised Ref-1 and pSTAT3 protein levels in MPNST patient samples from the IN Pediatric BioBank, in established MPNST cell lines, and in a new patient-derived tumour xenoline (RHT-92).