BTK and B-cell chronic lymphocytic leukemia: Treatment of primary CLL cells with idelalisib (GS-1101), ibrutinib, and fostamatinib (R406) which inhibit the PI3 kinase delta-specific isoform (PI3Kd), Bruton's tyrosine kinase (Btk) and spleen tyrosine kinase (Syk) respectively, results in inhibition of BCR signaling pathways, decreased cell proliferation, and disruption of chemokine mediated CLL cell migration [5],[6],[7],[8].