De novo CD5 ؉ diffuse large B-cell lymphoma (CD5 ؉ DLBCL) is known to have phenotypically and genotypically different characteristics than CD5 ؊ DLBCL and mantle cell lymphoma (MCL). To further characterize CD5 ؉ DLBCL, 109 patients with CD5 ؉ DLBCL were reviewed, and the results were compared with those of 384 CD5 ؊ DLBCL and 128 cyclin D1 ؉ MCL patients. Patients with CD5 ؉ DLBCL showed a higher age distribution (median, 66 years; P ‫؍‬ .0083) and a female predominance (male-female ratio, 49:60, P ‫؍‬ .011) compared with those with CD5 ؊ DLBCL. CD5 ؉ DLBCL was more closely associated with many aggressive clinical features or parameters than CD5 ؊ DLBCL: 69% older than 60 years (P ‫؍‬ .039), 34% with performance status greater than 1 (P ‫؍‬ .0016), 69% with serum lactate dehydrogenase level higher than normal (P < .0001), 62% with stage III/IV disease at diagnosis (P ‫؍‬ .0023), 35% with more than one extranodal site (P ‫؍‬ .023), and 40% with B symptoms (P ‫؍‬ .0031). The overall International Prognostic Index score was thus significantly higher for the patients with CD5 ؉ DLBCL than for those with CD5 ؊ DLBCL (P ‫؍‬ .00005). The most frequent site of extranodal involvement was bone marrow (28%), a higher frequency than that for CD5 ؊ DLBCL (P < .0001) but lower than that for cyclin D1 ؉ MCL (P ‫؍‬ .0015). Histopathologically, CD5 ؉ DLBCL showed centroblastic morphology except for 3 patients with immunoblastic disease, and interfollicular growth pattern (7%) and intravascular or intrasinusoidal infiltration (19%) were observed. Immunophenotypically, CD5 ؉ DLBCL was characterized by a CD5 ؉ CD10 ؊ CD19 ؉ CD20 ؉ CD21 ؊ CD23 ؊ cyclin D1 ؊ phenotype and a predominance of surface IgM. Of particular interest is that CD5 ؉ DLBCL was characterized by a survival curve significantly inferior to that for patients with CD5 ؊ DLBCL (P ‫؍‬ .0026). These findings suggest that CD5 ؉ DLBCL may constitute a unique subgroup of DLBCL.

The gene(s) responsible for natural killer (NK)-cell lymphoma/leukemia have not been identified. In the present study, we found that in NK-cell lymphoma lines (n ‫؍‬ 10) and specimens of primary lymphoma (n ‫؍‬ 10), levels of miR-21 and miR-155 expression were inversely related and were significantly greater than those found in normal natural killer (CD3 ؊ CD56 ؉ ) cells (n ‫؍‬ 8). To determine the functions of these microRNAs in lymphomagenesis, we examined the effects of antisense oligonucleotides (ASOs) tar- IntroductionNatural killer (NK)-cell lymphomas/leukemias are characterized groups of highly aggressive lymphoid malignancies, which are composed of "extranodal NK/T-cell lymphoma, nasal type" and "aggressive NK-cell leukemia." 1 Notably, these 2 subtypes show many similarities in their morphologic features, immunophenotypes, and genotypes and are invariably associated with EpsteinBarr virus (EBV), which suggests they may share the same genetic alterations. To assign a classification, the World Health Organization classification uses cytogenetic and molecular features to characterize lymphoma subtypes. 1 For example, it is known that various genomic translocations and genetic alterations, including BCL2, CCDN1, and c-MYC, occur in B-cell lymphomas. These disease-specific genetic translocations characterize lymphoma subtypes, such as follicular lymphoma characterized by BCL2 rearrangement, mantle-cell lymphoma characterized by CCDN1 rearrangement, and Burkitt lymphoma characterized by c-MYC rearrangement. However, although the World Health Organization classification recognizes NK-cell lymphomas/leukemias as distinct clinicopathologic entities, disease-specific translocations and the gene(s) affected in the 2 subtypes have not yet been identified. It was previously reported that a 6q deletion occurs in approximately 10% to 20% of NK-cell lymphomas/leukemias 2-7 ; however, this loss may not be disease specific because it has been observed in a variety of cancers, including solid tumors and hematologic malignancies. It is currently unclear whether the loss is a primary or progression-associated event.It was recently discovered that some microRNAs (miRNAs) are oncogenic in B-cell lymphomas. For example, aberrant overexpression of 2 miRNAs, miR-17-92 and miR-155, is closely associated with B-cell lymphomagenesis. 8 With respect to miR-17-92, we recently demonstrated that the polycistron can down-regulate CDKN1A/p21 in B-cell lymphomagenesis and promote cell-cycle regulation. 8 Furthermore, it is unlikely that aberrant expression of miRNAs is restricted to B-cell lymphomas, and it may occur in other lymphoma subtypes, including T/NK-cell lymphomas. In the present study, therefore, we used Northern and quantitative polymerase chain reaction (PCR) analyses to screen for and quantitatively assess miRNA expression in NK-cell lymphomas/leukemias and found that miR-21 and miR-155 were overexpressed in NK-cell lymphoma/leukemia. Moreover, the effects of antisense oligonucleotides (ASOs) revealed that miR-21 and miR-15...

BackgroundDe novo CD5-positive diffuse large B-cell lymphoma (CD5 + DLBCL) is clinicopathologically and genetically distinct from CD5-negative (CD5

Anaplastic large cell lymphoma (ALCL) is a subtype of non-Hodgkin's lymphoma characterized by the CD30+ large neoplastic cells and sometimes carries a t(2;5)(p23;q35). Recently, we found a novel hyperphosphorylated 80-kD protein tyrosine kinase, p80, in ALCLs with t(2;5). Subsequent cDNA cloning showed p80 to be a fusion protein of two genes, the novel tyrosine kinase gene and the nucleophosmin gene, in accordance with the sequence of the NPM/ALK gene (Morris et al, Science 263:1281, 1994). Meanwhile, the clinicopathologic features of p80-carrying ALCLs have remained unclear. Paraffin sections of 105 cases of ALCL were immunostained using anti-p80 antibody, and 30 of them were shown to express p80. Clinicopathologic comparison between p80-positive and -negative ALCLs showed that p80-positive cases occurred in a far younger patient age group (16.2 +/- 12.9 years; p80- negative cases, 51.0 +/- 22.3 years; P < .0001) and the patients showed a far better 5-year survival rate (79.8%; p80-negative group, 32.9%; P < .01). These data showed that p80-positive ALCL is a distinct entity both clinically and pathogenetically and should be differentiated from p80-negative ALCL.

Nine cases of peripheral T-cell lymphoma were identified in this study showing a distinctive growth pattern with partial distortion of the lymph node structure and prominent infiltration predominantly of marginal zones by medium-sized cells with clear cytoplasm and significant nuclear atypia. In the paracortical T-zone, there was a marked proliferation of high endothelial venules. Plasmocytosis and capsular fibrosis were other distinctive features. On immunohistochemistry, the lymphomas proved to be of T-helper cell origin (CD3+, CD4+, CD5+/-, CD8-, TIA1-) and proliferation was most prominent in the marginal zone of the regressive B-cell follicles. These cases have a characteristic morphology that may be sufficient to differentiate them as a variant from other peripheral T-cell lymphomas of the "not otherwise specified" group and to include them in the list of currently recognized lymphomas. Because of the distinct perifollicular growth pattern and incomplete effacement of the lymph node architecture, the differential diagnosis consists mainly of marginal zone B-cell lymphoma and reactive lesions.