SS is most strongly associated with T-helper cell 1 (GM-CSF, TNF, IFN-γ and IL-2), Th2 (IL-4 and IL-6) and macrophage (IL-1β, IL-6, IL-8, IL-12, TNF and VEGF) cytokines, as well as with IL-1Ra. This evidence concerns the gene IL2 and synovial sarcoma.