IL6 and histiocytic sarcoma: S100A4 also induces the expression of proinflammatory cytokines, such as IL-1β, IL-6 and TNF-α, acute phase reactants and some other S100 protein family members (e.g., 100A8 and S100A9) which are known to be involved in the pathogenesis of HS [1,11,16,25,26].