On the CLL cell surface, upregulation of NOTCH3 was associated with downregulation of CD23, suggesting that downregulation of the NOTCH2/FCER2 (CD23) axis, either spontaneously due to the lack of appropriate activation stimuli in vitro [18], or by gliotoxin treatment [32], is a prerequisite for NOTCH3 expression in CLL cells. Here, FCER2 is linked to B-cell chronic lymphocytic leukemia.