Results from one study implied a critical role for S1P signaling in MCL pathogenesis, as inhibition of S1P signaling via treatment with FTY-720 (an immunosuppressant that binds to four known S1P receptors (S1P1, 3-5) and inhibits downstream signaling) resulted in the time- and dose-dependent cytotoxicity of MCL tumor cells [40]. This evidence concerns the gene S1PR1 and mantle cell lymphoma.