Genetic aberrations in Notch1 and Notch2 arise in B-cell neoplastic diseases such as Hodgkin lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), and mantle cell lymphoma (MCL). The gene discussed is NOTCH1; the disease is diffuse large B-cell lymphoma.