As described in detail below and summarized in Table 1; Table 2, REL gains/amplifications predominantly occur in classical Hodgkin lymphoma (cHL) and in B cell non-Hodgkin lymphomas (B-NHL), particularly in diffuse large B cell lymphoma (DLBCL) and in primary mediastinal B cell lymphoma (PMBCL) as well as in transformed follicular lymphoma (tFL). The gene discussed is REL; the disease is diffuse large B-cell lymphoma.