Similarly, when we compared the effects of idelalisib with those of either fostamatinib or ibrutinib (all at 1 μM), we found that treatment of CLL cells with either of the latter two compounds had no effect on spontaneous S1PR1 expression (Supplemental Fig. 2G, 2H, respectively). The gene discussed is S1PR1; the disease is B-cell chronic lymphocytic leukemia.