MBTPS1 and inflammatory bowel disease: The function of sphingosine not only existed in its relation with other sterols in chemistry but it also causes huge biological influences through SphKs/S1P/S1PR1 axis, including physiological/pathological processes, e.g., hemopoietic system, lymphocytes internalization, allergic response, ischemia reperfusion injury, inflammatory bowel disease, and heterogeneity of carcinoma.