This would explain why CLL cells pre-treated with Duvelisib (a dual PI3K-δ/γ inhibitor) [69] or Ibrutinib (a Bruton’s tyrosine kinase inhibitor) [2,44] express lower amounts of CD23 and NOTCH3 and are less sensitive to apoptosis. This evidence concerns the gene FCER2 and B-cell chronic lymphocytic leukemia.