In particular, the first isoform-specific PI3K inhibitor, idelalisib, a selective δ-isoform inhibitor, has been approved in the USA and Europe for the treatment of chronic lymphocytic leukemia, follicular B-cell non-Hodgkin lymphoma, and small lymphocytic lymphoma; idelalisib will provide valuable information and references on PI3Kα inhibitors as drug candidates27. This evidence concerns the gene PIK3CA and B-cell chronic lymphocytic leukemia.