Elevated levels of C-X-C motif chemokine 10 (OR = 3.049, 95% CI = 1.428–6.513, p=0.004), Interleukin-4 (OR = 2.184, 95% CI = 1.218–3.915, p=0.009), Interleukin-7 (OR = 2.156, 95% CI = 1.191–3.901, p=0.011), T-cell surface glycoprotein CD5 (OR = 1.808, 95% CI = 1.083–3.020, p=0.024), Axin-1 (OR = 2.556, 95% CI = 1.072–6.096, p=0.034), and Fibroblast growth factor 5 (OR = 1.358, 95% CI = 1.021–1.807, p=0.035) were significantly associated with an increased incidence of SS, as detailed in Supporting Information Table S7. This evidence concerns the gene FGF5 and synovial sarcoma.