Also within mature B-cell neoplasms there is genetic evidence implicating the Notch pathway in disease pathogenesis, with Notch1 receptor mutations representing an adverse prognostic marker in chronic lymphocytic leukemia (CLL) [10], and constitutive Notch2 activation being reported in 8% of diffuse large B cell lymphomas (DLBCL) [11]. The gene discussed is NOTCH2; the disease is B-cell chronic lymphocytic leukemia.