Constitutive activation of BCR is a common hallmark of B cell malignancies, including chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), follicular lymphoma (FL), and diffuse large B cell lymphoma (DLBCL), observation that has led the design of a novel panel of inhibitors targeting kinases responsible for BCR signal transduction. The gene discussed is BCR; the disease is B-cell chronic lymphocytic leukemia.