BCR and B-cell chronic lymphocytic leukemia: In addition to tonic, ligand-mediated BCR signaling, chronic BCR activation can occur in the absence of antigen engagement [3], leading to aberrant, constitutive BCR activation in several B cell non-Hodgkin lymphoma (B-NHL) subtypes, including diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), follicular lymphoma (FL), and chronic lymphocytic leukemia (CLL) [4–7].