title: Expression of cyclin-dependent kinase 6 (cdk6) and frequent loss of CD44 in nasal-nasopharyngeal NK/T-cell lymphomas: comparison with CD56-negative peripheral T-cell lymphomas.
abstract: Lymphomas involving the nasal and nasopharyngeal region mainly include CD56-positive natural killer (NK)/T-cell lymphomas, CD56-negative peripheral T-cell lymphomas (PTL), and B-cell lymphomas. Among these, the CD56-positive lymphoma, presumably of an NK/T-cell nature, is frequently seen in Asian, Mexican, and South American patients. NK cells are proposed to be closer developmentally to T cells than to other lymphoid cells, because bipotential common progenitor cells of NK/T-cell lineage have been isolated. In this study, we collected 47 cases of nasal lymphoma and investigated the phenotypic difference between NK/T-cell lymphoma and PTL by examining the pattern of the developmentally differentially expressed molecules cdk6 (cyclin-dependent kinase 6), CD44, CD117, and by examining the rearrangement of the T-cell receptor gene (TcR-GR). cdk6, an essential regulator of the cell cycle in G1 progression, was over-expressed in a subset of cortical thymocytes, but absent in mature thymocytes. In contrast, CD44, a glycosylated adhesion molecule, was absent in cortical thymocytes, but present in mature thymocytes and peripheral activated T cells. We found both over-expression of nuclear cdk6 (n-cdk6) and frequent absence of CD44 in nasal CD56-positive NK/T-cell lymphomas, in contrast to most nasal CD56-negative PTL, which were CD44-immunoreactive with weak or no expression of n-cdk6. Almost all tested cases of NK/T-cell lymphoma displayed a germ-line configuration of TcR, without evidence of gene rearrangement. Thus, there seems to be a useful distinction between the classical NK/T type of nasal lymphoma (CD56+/n-cdk6+/CD44-/TcR-GR-) and PTL (CD56-/n-cdk6-/CD44+/TcR-GR+) involving the nasal region. The presence of Epstein-Barr virus does not seem to be a good marker for distinguishing between NK/T lymphoma and PTL involving the nasal region.
authors.affiliation: Department of Pathology, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei.
authors.forename: H C
authors.initials: HC
authors.lastname: Lien
authors.forename: C W
authors.initials: CW
authors.lastname: Lin
authors.forename: P H
authors.initials: PH
authors.lastname: Huang
authors.forename: M L
authors.initials: ML
authors.lastname: Chang
authors.forename: S M
authors.initials: SM
authors.lastname: Hsu
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis*; D019002:CD56 Antigen / Q000032:analysis*; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases; D005260:Female; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis*; D007694:Killer Cells, Natural / Q000276:immunology / Q000473:pathology*; D016399:Lymphoma, T-Cell / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D016411:Lymphoma, T-Cell, Peripheral / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D009669:Nose Neoplasms / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases / Q000032:analysis* / Q000235:genetics; D012189:Retrospective Studies
chemical_list: D015703:Antigens, CD; D019002:CD56 Antigen; D018960:Hyaluronan Receptors; D017346:Protein Serine-Threonine Kinases; C495911:CDK6 protein, human; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases