Additionally, BTK activity is suspected to play a central role in a number of other B-cell malignancies, including CLL, MCL, ALL, and multiple myeloma (Feldhahn et al., 2005; Hideshima et al., 2007; Mockridge et al., 2007; Cinar et al., 2013). Here, BTK is linked to B-cell chronic lymphocytic leukemia.