BTK and diffuse large B-cell lymphoma: Ibrutinib, a selective BTK inhibitor, has been approved for mantle cell lymphoma, chronic lymphocytic leukemia, Waldenström's macroglobulinemia, and marginal zone lymphoma (Gayko et al. 2015) and has demonstrated in vitro and in vivo efficacy in DLBCL, underscoring the role of BCR signaling in DLBCL (Wilson et al. 2015; Ezell et al. 2014; Mathews Griner et al. 2014).