The latter is predominantly associated with mutation of BTK and PLCG2. 6,7CARD11 mutation is identified in 10%-15% of DLBCL at presentation11 but is rarely identified (< 1%) in CLL.12 This suggests that the BCR signal in CLL and DLBCL may be qualitatively different and therefore that genetic mechanisms of resistance to BCR inhibition may also differ. Here, BTK is linked to B-cell chronic lymphocytic leukemia.