IBTK and B-cell chronic lymphocytic leukemia: The BTKi regulated DNA deamination genes mainly contain the APOBEC3 family genes (APOBEC3C, APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H) [21], and their expression levels showed a consistent reduction in CLL B cells from ibrutinib-treated patients (Fig. 1D).