IL1R1 and synovial sarcoma: Protein levels of IL‐1β (p = 0.004), IL‐1R1 (p = 0.04), TNF‐α (p = 0.02), IL‐17 (p = 0.011), IL‐17R (p = 0.025), L‐selectin (p = 0.029), IL‐8 (p = 0.018), CXCL1,2,3 (p = 0.006), CXCL16 (p = 0.036), MMP2 (p = 0.02), TIMP‐1 (p = 0.007), Siglec 5 (p = 0.001), Siglec 9 (p = 0.001), Fas (p = 0.047), FasL (p = 0.008), and CD40L (p = 0.021) were significantly higher in lesional SS skin samples compared to HCs.