MMP9 and synovial sarcoma: Protein levels of MPO (p = 0.014), IL‐8 (p = 0.001), MMP9 (p = 0.035) were significantly higher in SS lesional skin vs. HCs. CD3, CD163, TNF‐α, IL‐17, MMP2, VEGF showed a trend towards upregulation, although these differences were not statistically significant