HSPB1 and malignant peripheral nerve sheath tumor: It is possible that the presence of these cells in the malignant TME is correlated with the evidence of increased angiogenesis that we identified in the plasma proteomics of MPNST patients, where ANGPT2, CD40, CHI3L1, HSPB1, PGF, and VEGFA were found to be biomarkers of malignancy.