As a part of the sphingolipid metabolism, SPHK1 is the rate limiting enzyme of the rheostat and maintains the dynamic balance of the sphingolipid rheostat to reach relative homeostasis under normal physiological conditions [37], whereas elevated SPHK1 expression has been found in many types of cancer and leads to increased cell proliferation, migration capability, invasiveness, angiogenesis and inflammation with different oncogenic mechanisms [38]. Here, SPHK1 is linked to cancer.