BCR and diffuse large B-cell lymphoma: Despite the general consensus that BCR signaling is predominantly a requirement for ABC DLBCL as opposed to GCB DLBCL, GCB cell lines have been shown to rely upon spleen tyrosine kinase (SYK) [40] and cell lines including SU-DHL-16 have previously exhibited significant reductions in cell viability upon ibrutinib treatment [41].