The potent p110δ-specific inhibitor CAL-101 exhibits 40- to 300-fold selectivity for that particular isoform, as compared to other PI3K enzymes and is undergoing Phase I clinical evaluation in relapsed or refractory haematological malignancies (CLL, acute myeloid leukaemia, multiple myeloma and non-Hodgkin’s lymphoma) [127]. This evidence concerns the gene PIK3CD and B-cell chronic lymphocytic leukemia.