HLA-DR protein status predicts survival in patients with diffuse large B-cell lymphoma treated on the MACOP-B chemotherapy regimen

Loss of major histocompatibility class II (MHC class II) molecules on diffuse large B-cell lymphoma (DLBCL) has been associated with poor survival; however, none of these reports analysed a uniformly treated patient cohort. This study was designed to validate one MHC class II antigen, HLA-DR, as a prognostic marker in patients uniformly treated with the MACOP-B regimen. Immunostaining results were correlated with the international prognostic index (IPI) score and overall survival (OS). Of the 97 cases, 82 had interpretable staining. Of these, 52 expressed HLA-DR (median OS, 16.2 years) while 30 were negative (median OS, 4.2 years, P = 0.037). The IPI was also predictive of OS in the study group (P = 0.023). A Cox multivariate model established both IPI (P = 0.031) and HLA-DR (P = 0.04) as independent predictors of OS. This is the first demonstration of the prognostic relevance of HLA-DR in a uniformly treated DLBCL patient group.

Critical role of monocytes to support normal B cell and diffuse large B cell lymphoma survival and proliferation

Large B cell lymphomas can comprise numerous CD14+ cells in the tumor stroma, which raises the question of whether monocytes can support B cell survival and proliferation. We show that the coculture of monocytes with B cells from peripheral blood or from diffuse large B cell lymphoma enabled prolonged B cell survival. Under these conditions, diffuse large lymphoma B cells proliferated, and addition of B cell-activating factor of the TNF family (BAFF) and IL-2 enhanced cell division. Monocytes and dendritic cells (DC) had similar antiapoptotic activity on healthy B cells but displayed differences with respect to B cell proliferation. Monocytes and cord blood-derived CD14+ cells promoted B cell proliferation in the presence of an anti-CD40 stimulus, whereas DC supported B cell proliferation when activated through the BCR. DC and CD14+ cells were able to induce plasmocyte differentiation. When B cells were activated via the BCR or CD40, they released the leukocyte attractant CCL5, and this chemokine is one of the main chemokines expressed in diffuse large B cell lymphoma. The data support the notion that large B cell lymphoma recruit monocytes via CCL5 to support B cell survival and proliferation.

Nuclear CD40 interacts with c-Rel and enhances proliferation in aggressive B-cell lymphoma

CD40 is an integral plasma membrane-associated member of the TNF receptor family that has recently been shown to also reside in the nucleus of both normal B cells and large B-cell lymphoma (LBCL) cells. However, the physiological function of CD40 in the B-cell nucleus has not been examined. In this study, we demonstrate that nuclear CD40 interacts with the NF-kappaB protein c-Rel, but not p65, in LBCL cells. Nuclear CD40 forms complexes with c-Rel on the promoters of NF-kappaB target genes, CD154, BLyS/BAFF, and Bfl-1/A1, in various LBCL cell lines. Wild-type CD40, but not NLS-mutated CD40, further enhances c-Rel-mediated Blys promoter activation as well as proliferation in LBCL cells. Studies in normal B cells and LBCL patient cells further support a nuclear transcriptional function for CD40 and c-Rel. Cooperation between nuclear CD40 and c-Rel appears to be important in regulating cell growth and survival genes involved in lymphoma cell proliferation and survival mechanisms. Modulating the nuclear function of CD40 and c-Rel could reveal new mechanisms in LBCL pathophysiology and provide potential new targets for lymphoma therapy.

BCL6 programs lymphoma cells for survival and differentiation through distinct biochemical mechanisms

The BCL6 transcriptional repressor is the most commonly involved oncogene in diffuse large B-cell lymphomas (DLBCLs). Constitutive expression of BCL6 mediates lymphomagenesis through aberrant proliferation, survival, and differentiation blockade. Binding of BCL6 to the SMRT/N-CoR corepressors mediates the BCL6 survival effect in DLBCL. Although the basis for differentiation blockade is unknown in DLBCL, recent data suggest that BCL6 binding to the MTA3 corepressor might be involved. We report that BCL6 and MTA3 are coexpressed in normal germinal center B cells and DLBCL. Depletion of MTA3 in DLBCL cells induced a differentiation-related BCL6 target gene (PRDM1), but not target genes involved in survival. Accordingly, MTA3 and PRDM1 expression are mutually exclusive in germinal center B cells. We performed chromatin immunoprecipitation (ChIP)-on-chip mapping of the PRDM1 locus, identifying a novel BCL6 binding site on intron 3 of the PRDM1 gene, and show that BCL6 recruits MTA3 to this site. In DLBCL cells, MTA3 depletion induced plasmacytic differentiation but did not decrease viability of DLBCL cells. However, MTA3 depletion synergized with a specific BCL6 inhibitor that blocks SMRT/N-CoR binding to decrease DLBCL viability. Taken together, these results show that BCL6 regulates distinct transcriptional programs through the SMRT/N-CoR and MTA3 corepressors, respectively, and provides a basis for combinatorial therapeutic targeting of BCL6.

Prognostic impact of immunohistochemically defined germinal center phenotype in diffuse large B-cell lymphoma patients treated with immunochemotherapy

Germinal center (GC) and non-GC phenotypes are predictors of outcome in diffuse large B-cell lymphoma (DLBCL) and can be used to stratify chemotherapy-treated patients into low- and high-risk groups. To determine how combination of rituximab with chemotherapy influences GC-associated clinical outcome, GC and non-GC phenotypes were identified immunohistochemically from samples of 90 de novo DLBCL patients treated with rituximab in combination with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)–like regimen (immunochemotherapy). One hundred and four patients previously treated with chemotherapy served as a control group. Consistent with previous studies, chemotherapy-treated patients with immunohistochemically defined GC phenotype displayed a significantly better overall (OS) and failure-free survival (FFS) than the non-GC group (OS, 70% vs 47%, P = .012; FFS, 59% vs 30%, P = .001). In contrast, immunohistochemically defined GC phenotype did not predict outcome in immunochemotherapy-treated patients (OS, 77% vs 76%, P = ns; FFS, 68% vs 63%, P = ns). In comparison, International Prognostic Index (IPI) could separate the high-risk patients from low- and intermediate-risk groups (OS, 84% vs 63%, P = .030; FFS, 79% vs 52%, P = .028). We conclude that rituximab in combination with chemotherapy seems to eliminate the prognostic value of immunohistochemically defined GC- and non-GC phenotypes in DLBCL.

Prognostic significance of NPM-ALK fusion transcript overexpression in ALK-positive anaplastic large-cell lymphoma

In anaplastic large-cell lymphomas positive for anaplastic lymphoma kinase (ALK) protein, the ALK gene is most commonly fused to the NPM gene, and less commonly to TPM3, TFG, ATIC, and other rare genes. Although this lymphoma is generally associated with a favorable clinical outcome, 25% of the patients die of the disease within 5 years. In this study, we developed three assays, all of which can be used with archival formalin-fixed, paraffin-embedded tissues: (1) a sensitive reverse transcription-polymerase chain reaction (RT-PCR) assay for various X-ALK fusion genes, (2) a 5' rapid amplification of cDNA ends (RACE) assay to identify unknown fusion partners, and (3) a real-time RT-PCR assay to quantify the amount of the NPM-ALK fusion transcript. In 26 cases of ALK(+) anaplastic large-cell lymphoma, the RT-PCR assay showed that the ALK was fused to NPM in 21 cases, to TPM3 in three, and to TFG in one. The 5' RACE assay detected ATIC-ALK fusion in the remaining case. The real-time quantitative RT-PCR assay showed that the NPM-ALK transcript was over expressed in four of 20 quantifiable cases. Patients with NPM-ALK overexpression showed a significantly unfavorable overall survival compared with those with a low expression of this transcript. The RT-PCR and 5' RACE assays developed here may be useful for identification of known and unknown gene partners fused to the ALK gene. Overexpression of the NPM-ALK fusion transcript may be associated with a poor prognosis of the patients with ALK(+) anaplastic large-cell lymphomas.

NPM/ALK binds and phosphorylates the RNA/DNA-binding protein PSF in anaplastic large-cell lymphoma

The oncogenic fusion tyrosine kinase nucleophosmin/anaplastic lymphoma kinase (NPM/ALK) induces cellular transformation in anaplastic large-cell lymphomas (ALCLs) carrying the t(2;5) chromosomal translocation. Protein-protein interactions involving NPM/ALK are important for the activation of downstream signaling pathways. This study was aimed at identifying novel NPM/ALK-binding proteins that might contribute to its oncogenic transformation. Using a proteomic approach, several RNA/DNA-binding proteins were found to coimmunoprecipitate with NPM/ALK, including the multifunctional polypyrimidine tract binding proteinassociated splicing factor (PSF). The interaction between NPM/ALK and PSF was dependent on an active ALK kinase domain and PSF was found to be tyrosine-phosphorylated in NPM/ALK-expressing cell lines and in primary ALK(+) ALCL samples. Furthermore, PSF was shown to be a direct substrate of purified ALK kinase domain in vitro, and PSF Tyr293 was identified as the site of phosphorylation. Y293F PSF was not phosphorylated by NPM/ALK and was not delocalized in NPM/ALK(+) cells. The expression of ALK fusion proteins induced delocalization of PSF from the nucleus to the cytoplasm and forced overexpression of PSF-inhibited proliferation and induced apoptosis in cells expressing NPM/ALK. PSF phosphorylation also increased its binding to RNA and decreased the PSF-mediated suppression of GAGE6 expression. These results identify PSF as a novel NPM/ALK-binding protein and substrate, and suggest that PSF function may be perturbed in NPM/ALK-transformed cells.

Comparison of ataxia-telangiectasia mutated protein expression in diffuse large B-cell lymphomas of primary central nervous system and non-central nervous system origin

CONTEXT

The ataxia-telangiectasia mutated (ATM) gene encodes a nuclear 370-kd phosphoprotein known to be associated with chromosomal regions containing double-strand breaks. The mutations in the ATM gene may be involved in the development of some subtypes of sporadic lymphomas and leukemias. In primary central nervous system diffuse large B-cell lymphomas (PCNS DLBCLs), the pathogenetic role of ATM mutation has not been investigated.

OBJECTIVE

To investigate ATM protein expression in PCNS DLBCLs, in comparison with that in non-central nervous system (non-CNS) DLBCLs and to study the relationship of ATM protein loss with several clinicopathologic parameters.

DESIGN

This study included 42 cases of PCNS DLBCL and 33 cases of non-CNS DLBCL from immunocompetent patients. The ATM protein loss was analyzed by immunohistochemical staining. For the subclassification of DLBCL and analysis of the relationship between ATM and other prognostic markers, we performed immunohistochemical evaluation to detect the following markers: Bcl-6, CD10, multiple myeloma-1, CD138, Bcl-2, Ki-67, and p53.

RESULTS

The loss of ATM expression was statistically more frequent in PCNS DLBCLs (21/42 cases [50.0%]) than in non-CNS DLBCLs (0/33 cases [0.0%]; P < .001). The loss of ATM expression was not a prognostic marker in PCNS DLBCLs (P = .64). The loss of ATM expression had a strong correlation with the germinal center B-cell-like subtype (P = .01), a low Ki-67 labeling index (P = .03), and low Bcl-2 expression (P = .01) among several clinicopathologic parameters.

CONCLUSIONS

Our results suggest that the ATM protein is more strongly correlated with PCNS DLBCL lymphomagenesis than with non-CNS DLBCLs, especially in germinal center B-cell-like subtypes demonstrating low Ki-67 labeling indexes and low Bcl-2 expression.

Correlation between promoter hypermethylation of GSTP1 and response to chemotherapy in diffuse large B cell lymphoma

Glutathione-S-transferase P1 (GSTP1) and O6-methylguanine DNA methyltransferase (MGMT) are involved in drug-resistant to chemotherapeutic agents such as doxorubicin. In this study, prognostic significance of promoter hypermethylation and mRNA and protein expression of GSTP1 and MGMT together with promoter hypermethylation of death-associated protein kinase (DAPK) in diffuse large B cell lymphoma (DLBCL) was analyzed. Fifty-three patients with DLBCL, 24 men and 29 women, with age ranging from 23 to 91 (median 65), were analyzed. Genomic DNA and total RNA extracted from frozen samples of DLBCL were analyzed by methylation-specific polymerase chain reaction and quantitative reverse transcription polymerase chain reaction (RT-PCR) to determine promoter hypermethylation and mRNA expression of GSTP1, MGMT, and DAPK. Immunohistochemical analysis was performed to determine GSTP1 and MGMT expression at the protein level. Promoter hypermethylation of GSTP1, MGMT, and DAPK was detected in 12 (22.6%), 21 (39.6%), and 36 (67.9%) of 53 patients, respectively. Quantitative RT-PCR and immunohistochemistry did not show a correlation between methylation status and mRNA and protein expression of GSTP1 and MGMT. Patients with GSTP1 promoter hypermethylation showed a better 5-year overall survival rate than those without (100 vs 62.2%; p < 0.05). However, GSTP1 promoter hypermethylation was not an independent prognosticator in multivariate analysis. Methylation status of GSTP1 could be an indicator of drug response and a prognosticator for DLBCL.

Studies of a germinal centre B-cell expressed gene, GCET2, suggest its role as a membrane associated adapter protein

GCET2 (Germinal centre B-cell expressed transcript 2; also named HGAL) is a newly cloned gene that has been shown to be a useful marker for germinal centre (GC) B cells and GC B-cell derived malignancies, including follicular lymphomas and germinal centre B cell-like diffuse large B-cell lymphomas (GCB-DLBCLs), and is a useful prognosticator for DLBCLs. We report here the biochemical and biological properties of GCET2, which may help to determine its role in the GC reaction. GCET2 is constitutively localised in the plasma membrane but is excluded from lipid rafts. GCET2 does not have a transmembrane domain, and its membrane localisation is mediated by myristoylation and palmitoylation. GCET2 has five conserved putative tyrosine phosphorylation sites, and it can be phosphorylated following pervanadate treatment in B cells. By serially mutating the five tyrosines, the third and fourth tyrosines were found to be essential for GCET2 phosphorylation. GCET2 was phosphorylated when co-transfected into COS7 cells with protein tyrosine kinases (PTKs) LYN, LCK or SYK, and therefore it could be a substrate of these kinases in B cells. The third tyrosine site ((107)YENV) of GCET2 is a consensus GRB2 binding site, and GCET2 was found to associate with GRB2 through the third tyrosine following phosphorylation. Our data suggests that GCET2 may be an adaptor protein in GC B cells that transduces signals from GC B-cell membrane to the cytosol via its association with GRB2.

[Expression and correlation of Skp2 and p27(kip1) in 92 cases of non-Hodgkin's lymphoma]

OBJECTIVE

To investigate the expression and correlation of Skp2 and p27kipl in non-Hodgkin's lymphoma.

METHODS

The expression of Skp2, p27(kip1) and Ki-67 (the proliferation index)were detected in sections of 92 cases of non-Hodgkin's lymphoma (NHL) and 14 cases of reactive lymph nodes by immunohistochemistry and histopathology. The expression of Skp2 and p27(kip1) in 4 NHL cell lines were detected by Western blot.

RESULTS

The expression of Skp2 in NHL cases were significantly higher than that in reactive lymph nodes (except the germinal centers), positively correlated with proliferation activity, and an increasing tumor aggressiveness was associated with the increased expression of Skp2. The expression of p27(kip1) protein in NHL cases were significantly lower than that in reactive lymph nodes (except the germinal centers), negatively correlated with proliferation activity, and an increasing tumor aggressiveness was associated with decreased expression of p27(kip1). The statistical analysis indicated that there was no obvious correlation between Skp2 and p27(kip1) expression in NHL tissues.

CONCLUSION

The higher expression of Skp2 and lower expression of p27(kip1) in NHL tissues may play a role in the tumorigenesis and development of NHL.

[Distinction between lymphoma-like lesions and lymphoma of uterine cervix: a clinicopathologic study of 26 cases]

OBJECTIVE

To study the clinicopathologic features and differential diagnosis of lymphoma-like lesions and lymphoma of uterine cervix.

METHODS

Clinical data and hematoxylin and eosin-stained slides of 10 cases of lymphoma-like lesion and 16 cases of lymphoma of uterine cervix were reviewed. Immunohistochemical study for B- and T-cell markers and light chains (kappa, lambda) were performed on paraffin sections. The rearrangement status of immunoglobulin heavy chain (IgH) gene was analyzed with semi-nested polymerase chain reaction in 4 cases lymphoma-like lesion and 4 cases of lymphoma of uterine cervix.

RESULTS

The age of patients with lymphoma-like lesion ranged from 24 to 54 years (medium = 43 years). The lesion generally presented with cervical erosion or polyp. Microscopically, it is characterized by focal or diffuse superficial infiltration of immunoblast-like large B cells intermingled with a polymorphic population of inflammatory cells, including plasma cells, eosinophils and neutrophils. Maturation of the transformed large B cells was also noticed. On the other hand, the age of the patients with lymphoma of uterine cervix varied from 28 to 78 years (medium = 58 years). Cervical mass or diffuse enlargement of cervix were the commonest clinical findings. The cases included 12 examples of diffuse large B-cell lymphoma and 4 examples of follicular lymphoma. The former was characterized by a diffuse monomorphic population of large atypical lymphoid cells, while neoplastic follicles were identified in the latter. Neither polymorphic inflammatory infiltrates nor maturation phenomenon was found. The immunostaining for kappa and lambda light chains was inconclusive. Molecular study showed clonal rearrangement of IgH gene in all cases of cervical lymphoma, as well as 2 cases of lymphoma-like lesion.

CONCLUSIONS

The distinction between lymphoma-like lesion and lymphoma of uterine cervix depends primarily on the clinical and histopathologic features. Assay for rearrangement of IgH gene may be helpful in differential diagnosis, though monoclonality can be detected in some benign lesions as well.

[Effects of AKT protein kinase activation on biologic behavior of diffuse large B cell lymphoma cells]

OBJECTIVE

To observe the status of AKT and phospho-AKT (pAKT) in three diffuse large B cell lymphoma (DLBCL) cell lines, and to investigate the effects of AKT activation on biologic behavior of DLBCL cells.

METHODS

Three DLBCL cell lines, ly1, ly8 and ly10 were maintained in 10% FBS or serum free culture medium. The expression of AKT and status of pAKT were detected by Western blotting. LY294002, an inhibitor of PI3K, was used to suppress the level of pAKT. Flow cytometry combined with PI staining, AnnexinV-FITC assay and Brdu incorporation assay were used to analyze the parameters of the cell cycle, apoptosis and proliferation respectively.

RESULTS

There was constitutive activation of AKT in three DLBCL cell lines and the levels of pAKT were altered in the different environments. In 10% FBS culture medium, pAKT was higher than that in serum free culture medium in ly8 and ly10, however, pAKT in ly1 maintained in serum free culture medium was mildly higher than that in 10% FBS culture medium. When the cell lines ly1, ly8, ly10 were maintained in 10% FBS culture medium, the inhibitor LY294002 suppressed the level of pAKT efficiently in three DLBCL cell lines. The percentage of cells at S phase and the proliferation index were significantly decreased (P < 0.05) without an increase of apoptosis (P > 0.05).

CONCLUSIONS

Activation of AKT may play an important role in the development of DLBCL. It is closely related to the control of cell cycle and proliferation, but is not associated with apoptosis. LY294002 can inhibit cell growth by decreasing the levels of pAKT in DLBCL cell lines.

Intravascular large B-cell lymphoma of the uterus presenting as fever of unknown origin (FUO) and revealed by FDG-PET

Non-Hodgkin's lymphoma (NHL) is a common cause of Fever of Unknown Origin (FUO) but the presentation as a gynaecologic malignancy is exceedingly rare. To our knowledge, this represents the first report of an intravascular large B-cell lymphoma of the uterus presenting with fever of unknown origin. After a standard clinical work-up for FUO, the endometrial curettage directed by the finding of a localized fluoro-deoxyglucose Positron Emission Tomography (FDG-PET) hot spot in the pelvic area, yielded material revealing an intr avascular B-cell lymphoma. A total abdominal hysterectomy confirmed the presence of an intravascular large B-cell lymphoma in the lumina of small blood vessels of the uterus.

Cyclin-dependent kinase inhibitor seliciclib shows in vitro activity in diffuse large B-cell lymphomas

Despite recent improvements in treatment, a significant fraction of patients with diffuse large B-cell lymphoma (DLBCL) still fail therapy. Therefore, new therapeutic modalities are needed to advance the cure rate. Seliciclib (CYC202, R-roscovitine) is a purine analog developed as an inhibitor of CDK2/cyclin E CDK7/cyclin H and CDK9/cyclin T. Seliciclib has been shown to be active in B-cell neoplasms, such as mantle cell lymphoma, chronic lymphocytic leukemia and in multiple myeloma in vitro. The aim of this study was to assess the in vitro activity of seliciclib in DLBCL. The anti-proliferative activity of seliciclib was tested in nine human DLBCL cell lines and six DLBCL primary cell cultures. The effects of seliciclib on the cell cycle and on apoptosis, as well as on transcription-related proteins were assessed. The cell viability of all DLBCL cell lines and primary cells was reduced by seliciclib treatment. The IC50 for the cell lines ranged from 13 - 36 microm. The effect of seliciclib was independent of the genetic aberrations characterizing the cell lines. After seliciclib exposure cells accumulated in G2/M or in G1 phase, with most of the cells showing signs of apoptosis. Despite the clear cytotoxic effect and induction of apoptosis, this study could not identify a unique mechanism of action. The in vitro data suggest that seliciclib is an active agent in DLBCL. Its efficacy is apparently independent of the underlying chromosomal translocations characteristic of DLBCL. The drug might represent a new therapeutic agent in this lymphoma sub-type.

[Comparative study of heterogeneity of extranodal and nodal diffuse large B cell lymphoma]

OBJECTIVE

Primary nodal and extranodal diffuse large B-cell lymphoma (DLBCL) were investigated for the heterogeneity of histopathology and immunophenotype, and their relation to clinical stage, comparatively. Whether E2F1 can be used as a germinal center B cell (GCB) DLBCL marker was also discussed.

METHODS

Classification of histopathology and immunophenotype of 98 cases were studied by immunohistochemistry in tissue microarray.

RESULTS

Histopathologic morphology presented as: centroblastic (CB,88.8%, 87/98), immunoblastic (IB,5.1%, 5/98), anaplastic (ALCL,3.1%, 3/98), and T cell rich B cell lymphoma (TCRBCL,3.1%, 3/98). Of which, 31 cases were GCB DLBCL, 10 (20.8%, 10/48) nodal, and 21 extranodal (42%, 21/50, P=0.024). The rates of Stages I/II in nodal and extranodal area were 48.5% and 70%, respectively (P=0.015). The rate of Stage I/ II in GCB DLBCL (74.2%) were higher than in non-GCB DLBCL (50.7%, P=0.029). The CD10 positive rates were 36.8% and 17.1% in Stages I/II and III/IV, respectively, and had significant differences (P=0.033). The CD10 positive rates were 18.8% and 38% in nodal and extranodal area, respectively (P=0.035). The positive rates of E2F1 were 38.8% and 16.5% in GCB and non-GCB DLBCL, respectively, and had significant differences (P=0.016). The positive rate of E2F1 had positive relation with the expression of CD10 and Bcl-6 (P<0.05).

CONCLUSION

CB is the most type in 98 cases of DLBCL. The rate of GCB DLBCL was significant higher in extranodal than in nodal areas CD 10 can be used as a prognostic marker. The prognosis of GCB DLBCL is better than that of non-GCB DLBCL. The positive expression of E2F1 can be used as a marker of GCB DLBCL.

Clinicopathologic correlations of stage IE/IIE primary thyroid diffuse large B-cell lymphoma

BACKGROUND

We studied the clinicopathological characteristics and prognoses of localized stage thyroid diffuse large B-cell lymphoma (DLBCL).

PATIENTS AND METHODS

This study included 32 patients with stage I/IIE thyroid DLBCL. Their median age was 66 years, the male/female ratio was 10/22.

RESULTS

As to the cellular immunophenotype, CD20 was positive in 31/32, CD5 in 0/32, CD10 in 4/32, CD23 in 1/32, BCL2 in 14/30, and BCL6 in 24/32. Twelve cases showed abnormal karyotypes: two cases with t(8;14)(q24;q32), four cases with 3q27, two cases with 17p11, and four cases with other abnormal karyotypes. As for treatment, eight cases were treated with chemotherapy alone and 24 cases were treated with chemotherapy followed by radiotherapy. Complete response was achieved in 94%. The 5-year progression-free survival was 84% and the 5-year overall survival was 90% with a median follow-up period of 62 months. The germinal center B-cell (GCB) type had a significantly better prognosis than the non-GCB type.

CONCLUSION

Localized stage thyroid DLBCL is a disease with a relatively good prognosis. It is, however, a heterogeneous disease with regard to histological type and pathological state. Localized stage thyroid DLBCL has a good prognosis and it is that there are more GCB-type DLBCL lymphomas.

CD30 Activates Both the Canonical and Alternative NF-κB Pathways in Anaplastic Large Cell Lymphoma Cells

CD30 is a member of the tumor necrosis factor receptor superfamily whose expression is up-regulated on anaplastic large cell lymphoma (ALCL) and Hodgkin lymphoma (HL) cells. Many different outcomes of CD30 stimulation have been reported, including cell cycle arrest, apoptosis, and activation of the prosurvival transcription factor, NF-kappaB, although this last activity is much less well defined in ALCL cells. In order to better understand the signaling properties of CD30 in cancer, we established a system for the stimulation of CD30 with its physiological ligand. Using this system, CD30 was stimulated on ALCL and HL cells, and the subsequent CD30 signaling properties were characterized. We show that a fraction of ALCL cells rapidly underwent apoptosis following CD30 stimulation, whereas HL cells were unaffected. The surviving ALCL cells exhibited robust activation of both the canonical and alternative NF-kappaB pathways as measured by nuclear translocation of RelA, p50, RelB, and p52, and this culminated in the transactivation of classical NF-kappaB-responsive genes. With prolonged CD30 stimulation, ALCL cells underwent cell cycle arrest that correlated with expression of the cell cycle inhibitor p21(waf1). Furthermore, p21(waf1) expression and cell cycle arrest were found to depend predominantly on the canonical NF-kappaB pathway, since it was reversed by RNA interference-mediated suppression of RelA. In contrast, suppression of the p100/p52 NF-kappaB subunit had little effect on p21(waf1). These data reveal that in ALCL cells, in contrast to other cell types, CD30 stimulation elicits p21(waf1)-mediated arrest through the canonical but not the alternative NF-kappaB pathway.

Microvessel density and expression of vascular endothelial growth factor and its receptors in diffuse large B-cell lymphoma subtypes

Angiogenesis is known to play a major role in neoplasia, including hematolymphoid neoplasia. We assessed the relationships among angiogenesis and expression of vascular endothelial growth factor and its receptors in the context of clinically and biologically relevant subtypes of diffuse large B-cell lymphoma using immunohistochemical evaluation of tissue microarrays. We found that diffuse large B-cell lymphoma specimens showing higher local vascular endothelial growth factor expression showed correspondingly higher microvessel density, implying that lymphoma cells induce local tumor angiogenesis. In addition, local vascular endothelial growth factor expression was higher in those specimens showing higher expression of the receptors of the growth factor, suggesting an autocrine growth-promoting feedback loop. The germinal center-like and nongerminal center-like subtypes of diffuse large B-cell lymphoma were biologically and prognostically distinct. Interestingly, only in the more clinically aggressive nongerminal center-like subtype were microvessel densities significantly higher in specimens showing higher vascular endothelial growth factor expression; the same was true for the finding of higher vascular endothelial growth factor receptor-1 expression in conjunction with higher vascular endothelial growth factor expression. These differences may have important implications for the responsiveness of the two diffuse large B-cell lymphoma subtypes to anti-vascular endothelial growth factor and anti-angiogenic therapies.

The impact of Epstein-Barr virus status on clinical outcome in diffuse large B-cell lymphoma

To define prognostic impact of Epstein-Barr virus (EBV) infection in diffuse large B-cell lymphoma (DLBCL), we investigated EBV status in patients with DLBCL. In all, 380 slides from paraffin-embedded tissue were available for analysis by EBV-encoded RNA-1 (EBER) in situ hybridization, and 34 cases (9.0%) were identified as EBER-positive. EBER positivity was significantly associated with age greater than 60 years (P = .005), more advanced stage (P < .001), more than one extranodal involvement (P = .009), higher International Prognostic Index (IPI) risk group (P = .015), presence of B symptom (P = .004), and poorer outcome to initial treatment (P = .006). The EBER(+) patients with DLBCL demonstrated substantially poorer overall survival (EBER(+) vs EBER(-) 35.8 months [95% confidence interval (CI), 0-114.1 months] vs not reached, P = .026) and progression-free survival (EBER(+) vs EBER(-) 12.8 months [95% CI, 0-31.8 months] vs 35.8 months [95% CI, 0-114.1 months], respectively (P = .018). In nongerminal center B-cell-like subtype, EBER in situ hybridization positivity retained its statistical significance at the multivariate level (P = .045). Nongerminal center B-cell-like patients with DLBCL with EBER positivity showed substantially poorer overall survival with 2.9-fold (95% CI, 1.1-8.1) risk for death. Taken together, DLBCL patients with EBER in situ hybridization+ pursued more rapidly deteriorating clinical course with poorer treatment response, survival, and progression-free survival.

Expression of the RNA-binding protein VICKZ in normal hematopoietic tissues and neoplasms

BACKGROUND AND OBJECTIVES

VICKZ family members are RNA-binding regulatory proteins expressed during embryogenesis but not usually found in normal adult tissue. The presence of VICKZ in normal germinal centers (GC) prompted us to characterize the expression pattern of this protein in lymphoid and hematopoietic tissues.

DESIGN AND METHODS

We generated a pan-VICKZ antibody that recognized all three isoforms of VICKZ protein and screened 889 patients' samples by immunohistologic methods. We also analyzed the expression of VICKZ in normal hematopoiesis tissue by staining samples of tonsils, lymph nodes

RESULTS

VICKZ protein expression was documented for the first time in normal human GC and in follicular (126/165), mediastinal large B-cell (9/10), Burkitt (2/2), diffuse large B-cell (DLBCL, 155/200), lymphocyte-predominant Hodgkin's (12/13), classical Hodgkin's (101/108), and anaplastic large cell (6/8) lymphomas and in lymphoid and myeloid leukemias. Since DLBCL may derive from GC or non-GC B cells we performed hierarchical cluster analysis for VICKZ, HGAL, BCL6, CD10, MUM1/IRF4 and BCL2 which showed that VICKZ is expressed in both subtypes. In addition, VICKZ mRNA isoforms were differentially expressed in lymphoma subtypes and over 40% of DLBCL expressed hVICKZ2, an isoform not usually present in normal GC B cells.

INTERPRETATION AND CONCLUSIONS

We show that in normal lymphoid tissues VICKZ is expressed in GC lymphocytes but in lymphoid neoplasms its expression is not limited to GC-derived lymphoma subtypes. However, VICKZ exhibits differential expression in lymphoma subtypes and thus may be a marker of potential value in the diagnosis and study of hematopoietic neoplasia. The aberrant expression of its isoforms in DLBCL raises the possibility that these isoforms may be associated with different functions and suggests that further study of their role in normal and neoplastic lymphoid cells is warranted.

Expression of transmembrane adaptor protein PAG/Cbp in diffuse large B-cell lymphoma: immunohistochemical study of 73 cases

PAG/Cbp is a transmembrane adaptor protein involved in proximal immune signaling. It is expressed in reactive germinal centers (GC) of secondary lymphatic follicles and related malignant lymphomas. We studied PAG/Cbp expression in GC-like and non-GC-like diffuse large B-cell lymphoma (DLBCL) subtypes. Seventy-three cases of DLBCL identified among 155 malignant lymphomas were classified as GC-like DLBCL (CD10+ or CD10-, bcl-6+, and MUM1-) and non-GC-like DLBCL (CD10-, MUM1+ or CD10-, bcl-6+, MUM1+). PAG/Cbp was detected by monoclonal antibody MEM-255 following routine immunohistochemical procedures. Thirty-five of 40 GC-like DLBCLs (88%) and 20 of 33 non-GC-like DLBCL cases (61%) expressed PAG/Cbp. Four of 12 bcl-6-negative non-GC-like DLBCL cases (33%) were PAG/Cbp positive, and only 4 of 20 bcl-6-positive non-GC-like DLBCL cases (25%) were PAG/CBP negative. All 37 FL and all 5 Burkitt's lymphomas (BL) expressed PAG/Cbp, whereas all 6 mantle cell lymphomas (MCL) and 4 of 5 chronic lymphocytic leukemias (CLL/SLL) were PAG/Cbp negative. PAG/Cbp is a reliable GC marker. Its expression correlates with GC-like DLBC phenotype in a significant majority of cases. It is typically absent in MCL and SLL/CLL.