Zeta’s mouse monoclonal antibody recognizes BCL-6, a protein of 95kDa. BCL-6 is important for differential diagnosis of small B-cell lymphoma. Follicular lymphoma shows BCL-6 (and CD10) positivity whereas other small B-cell lymphomas are usually BCL-2 negative. Additionally, BCL-6 is an important prognostic marker in diffuse large B-cell lymphomas (DLBCL), where CD10, BCL-6 and MUM1/IRF4 are used to identify germinal center and activated B-cell phenotypes. Finally, BCL-6 can be valuable in distinguishing classical Hodgkin lymphoma from nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). The Reed-Sternberg cells of classical Hodgkin lymphoma are BCL-6 negative whereas the large (“L&H”) cells of NLPHL are BCL-6 positive. In contrast, anti-BCL-6 rarely stains mantle-cell lymphoma and MALT lymphoma.