Sphingolipids have long been known to play important roles in cellular metabolism and membrane biology, but the notion of sphingolipids as cellular signaling molecules has gained recognition only the last two decades. Bioactive sphingolipids, including ceramide, sphingosine and sphingosine 1-phosphate (S1P) are now appreciated as major regulators of multiple cellular processes, including cell proliferation, differentiation, survival, migration and immune responses. Our Lab is studying the role of S1P metabolism in chemo- and radioresistance, in bone metastasis, in hypoxia signaling and in chemoprevention using essentially prostate and renal cancers as models.