Immunohistochemical detection of CD10 with monoclonal antibody 56C6 on paraffin sections

We tested a total of 174 paraffin-embedded hematolymphoid neoplasias to determine whether CD10 can be specifically and sensitivity detected on paraffin sections using monoclonal antibody 56C6 after epitope retrieval. For 32 cases, results of CD10 detection by immunohistochemistry were compared with flow cytometric data. In only 1 case of follicle center lymphoma, divergent staining results were found with the detection of CD10 by flow cytometry but not by immunohistochemistry. Altogether, 22 of 28 follicle center lymphomas, 2 of 6 hairy cell leukemias, 14 of 34 diffuse large B-cell lymphomas, 3 of 3 Burkitt lymphomas, 4 of 5 precursor B-lineage acute lymphoblastic leukemias, and 2 of 4 T-lymphoblastic lymphomas were CD10+. Decalcification of bone marrow biopsy specimens did not diminish the staining intensity. All other cases, including 10 acute myeloid leukemias and a range of low-grade B-cell lymphomas, were CD10-. CD10 is reliably detectable with antibody 56C6 on paraffin sections using epitope retrieval. The antibody is especially useful for the subclassification of acute leukemias and low-grade B-cell lymphomas.