STAT3 and cancer: IL-6 may interact with pro-inflammation or immune cells to induce endocrine effects in an autocrine/paracrine manner, which exhibits intrinsic pro-tumorigenic actions such as cell proliferation, survival, migration, invasion, metastasis and extrinsic pro-tumorigenic actions such as modulate stromal cells to shape the microenvironment and cancer inflammation by activating STAT3 [39].