Momoko Nishikori

De novo CD5+ diffuse large B-cell lymphoma: results of a detailed clinicopathological review in 120 patients

Diffuse large B-cell lymphoma (DLBCL) constitutes the largest category of aggressive lymphomas, and is considered to have heterogeneous biological properties. De novo CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is a distinct entity. This study reveals the morphological spectrum of CD5+ DLBCL, shows that the incidence of central nervous system recurrence in this form of lymphoma in high, and confirms that CD5+ DLBCL frequently expresses BCL2 protein. Background De novo CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is clinicopathologically and genetically distinct from CD5-negative (CD5−) DLBCL and mantle cell lymphoma. The aim of this retrospective study was to clarify the histopathological spectrum and obtain new information on the therapeutic implications of CD5+ DLBCL. Design and Method From 1984 to 2002, 120 patients with CD5+ DLBCL were selected from 13 collaborating institutes. We analyzed the relationship between their morphological features and long-term survival. The current series includes 101 patients described in our previous study. Results Four morphological variants were identified: common (monomorphic) (n=91), giant cell-rich (n=13), polymorphic (n=14), and immunoblastic (n=2). Intravascular or sinusoidal infiltration was seen in 38% of the cases. BCL2 protein expression in CD5+ DLBCL was more frequent than in CD5− DLBCL (p=0.0003). Immunohistochemical analysis in 44 consecutive cases of CD5+ DLBCL revealed that 82% of these cases (36/44) were non-germinal center B-cell type DLBCL. The 5-year overall survival rate of the patients with CD5+ DLBCL was 38% after a median observation time of 81 months. Patients with the common variant showed a better prognosis than those with the other three variants (p=0.011), and this was confirmed on multivariate analysis. Overall, 16 patients (13%) developed central nervous system recurrence. Conclusions Our study revealed the morphological spectrum of CD5+ DLBCL, found that the incidence of central nervous system recurrence in this form of lymphoma in high, confirmed that CD5+ DLBCL frequently expresses BCL2 protein and showed that it is mainly included in the non-germinal center B-cell type of DLBCL.

B7‐H1 expression is regulated by MEK/ERK signaling pathway in anaplastic large cell lymphoma and Hodgkin lymphoma

B7‐H1 is a member of the B7 family that inhibits the function of T‐cells through its receptor programmed death‐1 (PD‐1). We examined B7‐H1 expression in anaplastic large cell lymphoma (ALCL) and Hodgkin lymphoma (HL) and found that it was constitutively expressed in both clinical samples and cell lines. In anaplastic lymphoma kinase–positive (ALK+) ALCL cells, B7‐H1 expression was suppressed by the blocking of extracellular signal‐regulated kinase (ERK) signaling and upregulated by the augmentation of ERK activity by phorbol 13‐myristate 12‐acetate stimulation, suggesting that B7‐H1 expression is regulated by ERK signaling pathway in ALCL. ERK is one of the downstream mediators of nucleophosmin (NPM)/ALK signaling in ALK+ALCL, and pharmacological inhibition of ALK was shown to dephosphorylate ERK and down‐regulate B7‐H1. The involvement of NPM/ALK in B7‐H1 expression was also demonstrated by introducing the construct into human non‐ALCL lymphoid cell lines, which resulted in B7‐H1 expression. In the case of HL, B7‐H1 expression was shown to be dependent on the ERK and p38 mitogen‐activated protein kinase (MAPK) signaling pathways. These results suggest that B7‐H1 expression is controlled by common ERK signaling pathways in ALCL and HL cells. Our findings provide a potentially effective immunotherapeutic strategy for these B7‐H1‐expressing tumors. (Cancer Sci 2009)

CD5-positive diffuse large B-cell lymphoma: a retrospective study in 337 patients treated by chemotherapy with or without rituximab

BACKGROUND CD5-positive (CD5+) diffuse large B-cell lymphoma (DLBCL) shows poor prognosis and frequent central nervous system (CNS) relapses under anthracycline-containing chemotherapy. The aim of this study was to determine the prognosis and CNS relapse incidence of CD5+ DLBCL in the rituximab era. PATIENTS AND METHODS We analyzed 337 patients with CD5+ DLBCL who received chemotherapy with (R-chemotherapy group; n = 184) or without (chemotherapy group; n = 153) rituximab. RESULTS No significant difference was found in clinical background comparisons between the two groups. In the R-chemotherapy group, 60% of the patients were older than 65 years at diagnosis. Both the complete response rate and overall survival (OS) were significantly better in the R-chemotherapy group (P = 0.0003 and P = 0.002, respectively). Multivariate analysis confirmed that chemotherapy without rituximab was associated with unfavorable OS. However, the probability of CNS relapse did not differ between the two groups (P = 0.89). The CNS relapse was strongly associated with short OS (P < 0.0001). In the R-chemotherapy group, 83% of patients who experienced CNS relapse had parenchymal disease. CONCLUSIONS Our results indicate that rituximab improves the OS of patients with CD5+ DLBCL but does not decrease the CNS relapse rate. More effective treatments with CNS prophylaxis are needed for CD5+ DLBCL patients.

A Clinical, Pathological, and Genetic Characterization of Methotrexate-associated Lymphoproliferative Disorders

Objective. Methotrexate-associated lymphoproliferative disorders (MTX-LPD) often regress spontaneously during MTX withdrawal, but the prognostic factors remain unclear. The aim of our study was to clarify the clinical, histological, and genetic factors that predict outcomes in patients with MTX-LPD. Methods. Patients with MTX-LPD diagnosed between 2000 and 2012 were analyzed retrospectively regarding their clinical course, site of biopsy, histological typing, Epstein-Barr virus (EBV) in situ hybridization and immunostaining, and HLA type. Results. Twenty-one patients, including 20 with rheumatoid arthritis (RA) and 1 with polymyositis, were analyzed. The mean dose of MTX was 6.1 mg/week and the mean duration of treatment was 71.1 months. Clinically, 5 patients were diagnosed with EBV-positive mucocutaneous ulcer (EBVMCU) and had polymorphic histological findings. The proportion of those patients successfully treated solely by withdrawal of MTX was significantly greater than that of those without EBVMCU (75% vs 7.7%, p = 0.015). The HLA-B15:11 haplotype was more frequent in patients with EBV+ RA with MTX-LPD than in healthy Japanese controls (p = 0.0079, Bonferroni’s method). EBV latency classification and HLA typing were not associated with the prognosis of MTX-LPD in our cohort. Conclusion. Our data demonstrate that patients in the EBVMCU, a specific clinical subgroup of MTX-LPD, had a better clinical outcome when MTX was withdrawn than did other patients with MTX-LPD.

Requirement of Non-canonical Activity of Uracil DNA Glycosylase for Class Switch Recombination

Activation-induced cytidine deaminase (AID) and uracil DNA glycosylase (UNG) are required for class switch recombination (CSR). AID is involved in the DNA cleavage step of CSR, but the precise role of UNG is not yet understood. Mutations and deletions are footprints of abortive DNA cleavage in the immunoglobulin switch region in splenic B cells stimulated to undergo CSR. However, a UNG deficiency did not reduce the number of such footprints, indicating UNG is dispensable for the DNA cleavage step. Mutagenesis experiments revealed that the role of UNG in CSR depends on its WXXF motif. This motif is also essential for the interaction of UNG with the HIV viral peptide Vpr, which recruits UNG to the HIV particle. Furthermore, exogenous Vpr had a dominant-negative effect on CSR. These results suggest that UNG is recruited to the CSR machinery through its WXXF motif by a Vpr-like host factor and plays a novel non-canonical role in a CSR step that follows DNA cleavage.

The gene for interleukin-21 receptor is the partner of BCL6 in t(3;16)(q27;p11), which is recurrently observed in diffuse large B-cell lymphoma.

BCL6 translocation affecting the chromosomal band 3q27 can involve a number of non-immunoglobulin (non-IG) gene loci as partners. We report here that the gene for interleukin-21 receptor (IL-21R) is the partner of BCL6 in t(3;16)(q27;p11) translocation. The two breakpoints on 16p11 of a lymphoma cell line YM and case no. 1012 with diffuse large B-cell lymphoma, both of which carried t(3;16), were localized within the ∼27-kb intron 1 of IL-21R. As a result of t(3;16), the promoter region of IL-21R was substituted for the regulatory sequences of BCL6 in the same transcriptional orientation. Reverse transcriptase-mediated polymerase chain reaction revealed chimeric mRNA consisting of two non-coding exons 1a/1b of IL-21R and coding exons of BCL6 in both lymphoma cells. Fluorescence in situ chromosomal hybridization of YM metaphase cells revealed fusion signals that contained both the BCL6 and IL-21R sequences on the der(3)t(3;16) chromosome. IL-21R was actively transcribed in YM cells, while BCL6 that was under the control of the IL-21R promoter was only moderately expressed at the mRNA and protein level. We constructed expression plasmid of BCL6 that followed the promoter sequences of IL-21R. COS-7 cells transiently transfected with the plasmid expressed high level Bcl-6 protein and displayed nuclear staining with a characteristic punctate pattern by immunofluorescence, indicating that expression of BCL6 can be enhanced by t(3;16). This study added to the list of non-IG partners of BCL6 translocations a new class of gene, i.e. cytokine receptor gene, the expression of which is closely associated with lymphoid cells.

Stimulation of CD30 in anaplastic large cell lymphoma leads to production of nuclear factor-κB p52, which is associated with hyperphosphorylated Bcl-3

Anaplastic large cell lymphoma (ALCL) and Hodgkin lymphoma (HL) express CD30 at high levels, but stimulation of this molecule has been reported to induce contradictory effects. To elucidate the molecular mechanism of CD30‐mediated apoptosis of ALCL, we compared the gene expression profiles of t(2;5)(p23;q35)‐positive ALCL with those of HL altered by CD30 agonistic stimulation. The results showed that BCL3, the high‐level expression of which in ALCL was previously reported, was further upregulated in response to CD30 stimulation, along with several pro‐apoptotic genes. Bcl‐3 protein was present as an intermediate phospho‐form in the resting‐state ALCL, becoming hyperphosphorylated (Bcl‐3P) upon stimulation. We next found that the stimulation promoted de novo synthesis of the nuclear factor (NF)‐κB2/p100 precursor as well as processing to p52, and a series of immunoprecipitation and western blotting analyses consistently showed association of Bcl‐3P with p52 in CD30‐stimulated ALCL. An electrophoretic mobility shift assay revealed the induction of κB binding activity of the p52 homodimer, and nuclear colocalization of Bcl‐3 and p52 was demonstrated in anaplastic lymphoma kinase‐positive ALCL tumor tissues by immunohistochemistry. As Bcl‐3 can act as an antirepressor or transactivator or both, we propose that the (p52)2/Bcl‐3P ternary complex, which is specifically induced in CD30‐stimulated ALCL, can modulate expression of apoptosis‐related genes regulated by NF‐κB, thereby accounting for CD30‐mediated apoptosis of ALCL. (Cancer Sci 2005; 96: 487–497)

Plasmin inhibitor reduces T-cell lymphoid tumor growth by suppressing matrix metalloproteinase-9-dependent CD11b + /F4/80 + myeloid cell recruitment

Activation of the fibrinolytic system during lymphoma progression is a well-documented clinical phenomenon. But the mechanism by which the fibrinolytic system can modulate lymphoma progression has been elusive. The main fibrinolytic enzyme, plasminogen (Plg)/plasmin (Plm), can activate matrix metalloproteinases (MMPs), such as MMP-9, which has been linked to various malignancies. Here we provide the evidence that blockade of Plg reduces T-cell lymphoma growth by inhibiting MMP-9-dependent recruitment of CD11b+F4/80+ myeloid cells locally within the lymphoma tissue. Genetic Plg deficiency and drug-mediated Plm blockade delayed T-cell lymphoma growth and diminished MMP-9-dependent CD11b+F4/80+ myeloid cell infiltration into lymphoma tissues. A neutralizing antibody against CD11b inhibited T-cell lymphoma growth in vivo, which indicates that CD11b+ myeloid cells have a role in T-cell lymphoma growth. Plg deficiency in T-cell lymphoma-bearing mice resulted in reduced plasma levels of the growth factors vascular endothelial growth-A and Kit ligand, both of which are known to enhance myeloid cell proliferation. Collectively, the data presented in this study demonstrate a previously undescribed role of Plm in lymphoproliferative disorders and provide strong evidence that specific blockade of Plg represents a promising approach for the regulation of T-cell lymphoma growth.

Coexistent Rearrangements of c- MYC , BCL2 , and BCL6 Genes in a Diffuse Large B-Cell Lymphoma

We present a patient with stage III de novo diffuse large B-cell lymphoma. The lymphoma cells showed mature B-cell immunophenotype but lacked surface immunoglobulin (Ig) expression. Long-distance and long-distance inverse polymerase chain reaction assays to detect the oncogene/Ig gene rearrangement revealed that the cells carried 3 independent fusion genes, namely, c-MYC/Ig heavy chain gene (IgH), BCL2/IgH, and Ig λ light chain gene/BCL6.Thus, the lymphoma cells concurrently carried t(8;14)(q24;q32), t(14;18)(q32;q21), and t(3;22)(q27;q11), which developed in association with class switching, V/D/J recombination, and somatic hypermutation, respectively. The lymphoma responded to chemoradiotherapy, and the patient has been well for 2 years, suggesting that multiple oncogene rearrangements may not necessarily be associated with poor clinical outcome.

Heterogeneous breakpoints on the immunoglobulin genes are involved in fusion with the 5' region of BCL2 in B-cell tumors

The 5′flanking region of the BCL2 gene (5′‐BCL2) is a breakpoint cluster of rearrangements with immunoglobulin genes (IGs). In contrast to t(14;18)(q32;q21) affecting the 3’region of BCL2, 5′‐BCL2 can fuse to not only the heavy chain gene (IGH), but also two light chain gene (IGL) loci. We report here cloning and sequencing of a total of eleven 5′‐BCL2/IGs junctional areas of B‐cell tumors, which were amplified by long‐distance polymerase chain reaction‐based assays. The breakpoints on 5′‐BCL2 were distributed from 378 to 2312 bp upstream of the translational initiation site and, reflecting the alteration of regulatory sequences of BCL2, 5′‐BCL2/IGs‐positive cells showed markedly higher levels of BCL2 expression than those of t(14;18)‐positive cells. In contrast, the breakpoints on the IGs were variable. Two 5′‐BCL2/IGH and two 5′‐BCL2/IGLK junctions occurred 5’of the joining (J) segments, suggesting operation of an erroneous variable (V)/diversity (D)/J and V/J rearrangement mechanism. However, two other 5′‐BCL2/IGH junctions affected switch regions, and the K‐deleting element, which is located 24 kb downstream of the constant region of IGLK, followed the 5′‐BCL2 in another case. One 5′‐BCL2/IGLK and two 5′‐BCL2/IGLλ junctions involved intronic regions where the normal recombination process does not occur. In the remaining one case, the 5′‐BCL2 fused 3’of a Vλ, gene that was upstream of another Vλ/Jλ complex carrying a non‐producing configuration, indicating that the receptor editing mechanism was likely involved in this rearrangement. Our study revealed heterogeneous anatomy of the 5′‐BCL2/IGs fusion gene leading to transcriptional activation of BCL2, and suggested that the mechanisms underlying the formation of this particular oncogene/IGs recombination are not identical to those of t(14;18).