Importantly, blocking the BCR pathway with the BTK inhibitor ibrutinib or with the PI3K inhibitor LY294002 did not alter CE or the basal Ca2+ level (data not shown) which is in agreement with Muggen report who failed to associate the basal Ca2+ level in CLL B cells with the FR2/3 amino-acid sequence. Here, BCR is linked to B-cell chronic lymphocytic leukemia.