IL6 and cancer: The effects of S1P on the interaction between cancer and the microenvironment include the following: (1) S1P produced by cancer cells acts on cancer cells themselves to promote proliferation, migration, and viability; (2) S1P produced by cancer cells acts on the microenvironment to induce vascular and lymphangiogenesis, immune responses, chronic inflammation, and stromal reactions; and (3) cytokines, such as IL-6 and TNF-α, produced by cancer cells act on stromal cells in the microenvironment, and the stromal cells produce S1P and affect the cancer cells [32,179,180].