IL6(Interleukin-6) is a multifunctional protein, that plays critical roles in host defense, immune response and hematopoiesis. IL6 is constitutively expressed by epidermal Langerhans cells and its expression is induced in stimulated keratinocytes. IL6 induces proliferation or differentiation in many cell types including B cells, thymocytes and T cells. IL6, in concert with TGF-β, is important for developing Th17 responses. IL6 binds to IL6Rα and through this association induces gp130 homodimerization. Research studies have shown that IL6, through increasing expression of proangiogenic VEGF, may also contribute to metastatic breast cancer.