CD40 and synovial sarcoma: Additional pro-inflammatory markers elevated in SS include: CD40/CD40 ligand, CD56, G-CSF, myeloperoxidase, IL-5, IL-8 IL-12, IL-13, L-selectin, MMP-2, MMP-9, Sialic acid-binding immunoglobulin-type lectin (Siglec) 5, Siglec 9, Transforming growing factor β (TGF-β), TIMP-1, TNF α, and VEGF (127, 524, 558–560, 562, 568, 569).