TNF and synovial sarcoma: When healthy control SGSCs from passages 1–4 were incubated with a cocktail of proinflammatory cytokines at concentrations matching those found in the serum of patients with primary SS (IFNα 500 pg/ml, TNF 40 pg/ml, and IL‐6 30 pg/ml) 26, we observed initially a significant increase in organoid formation efficiency, followed by a decrease to significantly below the levels in control cells (Figures 3A and B).