title: Immunoreactivity of CD99 in non-Hodgkin's lymphoma: unexpected frequent expression in ALK-positive anaplastic large cell lymphoma.
abstract: To verify the spectrum of CD99-expressing lymphoid malignancy, an immunohistochemical study for CD99 was carried out in 182 cases of non-Hodgkin's lymphoma, including 21 lymphoblastic lymphomas, 11 small lymphocytic lymphomas, 9 mantle cell lymphomas, 12 follicular lymphomas, 37 diffuse large B cell lymphomas, 18 Burkitt's lymphomas, 28 NK/T-cell lymphomas, 8 angioimmunoblastic T-cell lymphomas, 23 peripheral T-cell lymphomas, unspecified, and 15 systemic anaplastic large cell lymphomas. CD99 was positive in all T-lymphoblastic lymphomas and in 60% of B-lymphoblastic lymphomas. Majority of T and NK cell lymphomas were negative for CD99, except anaplastic large cell lymphomas (ALCLs). Eight of 15 cases (54%) of ALCLs reacted with anti CD99 antibody. Seven of 10 (70%) ALK positive ALCLs expressed CD99, whereas only 1 of 5 (20%) ALK negative ALCLs were positive. Of the mature B-cell lymphomas, 5.4% (2/37) of diffuse large B cell lymphomas and 11.1% (2/18) of Burkitt's lymphomas expressed CD99. In conclusion, CD99 is infrequently expressed in mature B and T cell lymphomas, except ALK-positive ALCL. High expression of CD99 in ALK-positive ALCL is unexpected finding and its biologic and clinical significances have yet to be clarified.
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Chang Ohk
authors.initials: CO
authors.lastname: Sung
authors.forename: Young H
authors.initials: YH
authors.lastname: Ko
authors.forename: Sanghui
authors.initials: S
authors.lastname: Park
authors.forename: Kihyun
authors.initials: K
authors.lastname: Kim
authors.forename: Wonseog
authors.initials: W
authors.lastname: Kim
mesh_terms: D000071443:12E7 Antigen; D000077548:Anaplastic Lymphoma Kinase; D015703:Antigens, CD / Q000378:metabolism*; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D016403:Lymphoma, Large B-Cell, Diffuse / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D008228:Lymphoma, Non-Hodgkin / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D011505:Protein-Tyrosine Kinases / Q000276:immunology / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases