Specific Lymphoma Subtypes Research Articles

Methylation reversal in high-grade B lymphoma cell lines and novel epigenetic changes conserved between immunocompetent and HIV-positive hosts

8585 Background: Methylation-dependent transcriptional silencing is an important mechanism of tumour suppressor gene inactivation in neoplasia, including lymphoma. Methods: Pharmacological “unmasking” of transcriptionally silenced genes in B lymphoma cell lines was achieved using 5' deazacytidine ± Trichostatin A and subsequent analysis of mRNA levels on micro-array. Candidate genes thus identified, were further analysed by qPCR, methylation-specific PCR (MSP) and bisulphite sequencing in B lymphoma cell lines and by MSP in clinical samples from sporadic (immunocompetent) (18 cases) and HIV-infected patients (14 cases). Samples in both patient groups were diffuse large B cell lymphoma (DLBCL) and Burkitt's lymphoma (BL). Additionally, we analysed 8 cases of marginal zone lymphoma (MZL) from the immunocompetent group. Results: We report the identification of 13 novel genes, not previously described in the literature, which are subject to methylation-dependent transcriptional silencing in high-grade lymphoma and whose expression can be reactivated by demethylating agents. The novel genes encode proteins involved in diverse functional classes and include pro-apoptotic members of the p53 pathway (Scotin), transcriptional regulators (Baz2B) and regulators of telomerase (Smrf2). The frequency of methylation in individual genes varied from approximately 10% to 75% in specific lymphoma subtypes, but was in general similar in high grade lymphomas in immunocompetent and HIV-infected hosts. Conclusions: Using pharmacological reversal of methylation, we have identified a number of genes, not previously implicated in human neoplasia, which are subject to transcriptional silencing in high-grade B lymphomas. The similar frequencies of methylation, observed in immunocompetent and HIV positive patients implies that the genes are fundamental in suppression of lymphomagenesis. Detection of methylated DNA of one or more of these genes may have utility as biomarkers of clinical outcome in each patient group. No significant financial relationships to disclose.

B Cells with BCL2/IGH Translocation Compose a Distinctive Cell Population That May Serve as a Reservoir of Lymphoma of Germinal Center B-Cell Type.

BCL2/IGH translocation is a hallmark of follicular lymphoma and diffuse large B-cell lymphoma of germinal center B-cell type. Although being a strong determinant of these histological subtypes, this translocation is considered to be insufficient by itself and further gene alterations are necessary for cellular transformation. In Eμ-BCL2 transgenic (Tg) mice, B-lineage cells are increased by several-fold compared to wild-type (WT) mice, but only 5–15 % of them develop disease in the first year of life. To clarify how the BCL2 translocation contributes to the development of specific lymphoma subtypes, we created two types of chimeric mouse models to characterize the biological features of BCL2-overexpressing B cells in normal individuals. First, we introduced CD19 promoter-driven BCL2 and its mutant genes to a minor population of murine bone marrow cells by using a lentiviral vector system and transplanted into irradiated mice. BCL2-overexpressing B cells showed increased follicular and reduced marginal zone populations. The same phenotypic shift was observed in B cells introducing BCL2-Y28F mutant that retained anti-apoptotic function, but a defective mutant BCL2-G142A and a mock vector did not affect B-cell phenotype. Additionally, BCL2-introduced B cells showed decreased cell size compared to those introduced BCL2-G142A and mock vectors. To assess the functional alteration of BCL2-overexpressing B cells, TNP-Ficoll binding experiment was performed. The result showed diminished T-cell independent response in parallel with decreased marginal zone B cells. The low transformation frequency of B cells in Eμ-BCL2 Tg mice has been partly explained by their propensity to reside in the G0 phase of the cell cycle (reviewed in Oncogene, 18:5268,1999). We hypothesized that the microenvironment of B cells in Eμ-BCL2 Tg mice might be altered by abnormal B cells themselves. To evaluate the influence of the different microenvironments on BCL2-overexpressing B cells, we next made Eμ-BCL2/CAG-GFP double Tg mice and transferred their bone marrow mononuclear cells into WT or Eμ-BCL2 Tg mice. Blastic cell population of BCL2+GFP+ B cells was larger in those transferred to WT mice compared to those transferred to Eμ-BCL2 Tg mice, regardless of the same phenotypic preference toward follicular B cells. BrdU uptake experiments demonstrated continuous cell cycle progression of the BCL2+GFP+ B cells in WT mice but repressed cell cycle of those in Eμ-BCL2 Tg mice. In immunohistochemical analysis, splenic follicles were disorganized with reduced follicular dendritic cells and inadequate T cell accumulation in Eμ-BCL2 Tg mice. Functional impairment of splenic follicles in Eμ-BCL2 Tg mice might be caused by decreased marginal zone B cell subset, as the antigen capture and delivery by marginal zone B cells was reported to play an important role in the development of follicular dendritic cells. To understand the fate of BCL2-overexpressing B cells after stimulation, we finally assessed their terminal differentiation capacity in vitro. Plasma cell differentiation was suppressed in B cells derived from Eμ-BCL2 Tg mice under either LPS or anti-IgM antibody stimulation. BCL2 is reported to impede the activity of transcription factor NF-AT (Proc Natl Acad Sci 93:9545, 1996; Nature 386:728, 1997), and we found that calcineurin inhibitor FK506 suppressed plasma cell differentiation of WT B cells. Gene regulation patterns of the Eμ-BCL2+ B cells were similar to B cells stimulated in the presence of FK506 as well, suggesting that repressed terminal differentiation in Eμ-BCL2+ B cells was partly caused by the suppressed activity of NF-AT. In summary, BCL2-deregulated B cells preferentially differentiate into follicular B cells, and as a result of decreased terminal differentiation in addition to their anti-apoptotic property, they may be obliged to survive and recirculate as memory B cells, and accumulate genetic abnormalities while they repeatedly pass through the germinal center. As the germinal center is the particular site where they can counterbalance the cell cycle-retarding effect of BCL2, it may be a specific place for generating lymphoma triggered by BCL2/IGH translocation. Our results emphasize the importance of the microenvironment of pre-malignant cells during transformation process, and suggest that a simple transgenic mouse model may not be always appropriate for the study of oncogenesis.

The utility of t(14;18) in understanding risk factors for non-Hodgkin lymphoma.

Characteristic chromosomal abnormalities are associated with specific histological subtypes of non-Hodgkin lymphoma (NHL). The chromosomal translocation t(14;18)(q32;q21) is one of the most common chromosomal abnormalities in NHL, occurring in 70%-90% of cases of follicular lymphoma, 20%-30% of diffuse large B-cell lymphoma, and 5%-10% of other less common subtypes. The t(14;18)-positive NHL may represent a homogenous group and, consequently, increase etiologic specificity in epidemiological studies. Although the t(14;18) has important clinical ramifications, its etiologic significance remains to be determined. Two population-based, case-control studies addressed this issue by evaluating potential risk factors for t(14;18)-positive and t(14;18)-negative subgroups of NHL. Both studies found that the association between pesticide exposures and risk of NHL was largely limited to t(14;18)-positive NHL cases. However, the findings regarding cigarette smoking, family history of hematopoietic cancer, and hair dye use were not entirely consistent. These results indicate that defining subgroups of NHL according to t(14;18) status may be useful for etiologic research, particularly for exposures that are genotoxic or may contribute to the development of NHL through pathways involving the t(14;18). Studies to further evaluate these associations and delineate the effects of various exposures in other genetically defined subgroups of NHL are warranted.

Information Preserving Component Analysis: Data Projections for Flow Cytometry Analysis

Flow cytometry is often used to characterize the malignant cells in leukemia and lymphoma patients, traced to the level of the individual cell. Typically, flow-cytometric data analysis is performed through a series of 2-D projections onto the axes of the data set. Through the years, clinicians have determined combinations of different fluorescent markers which generate relatively known expression patterns for specific subtypes of leukemia and lymphoma - cancers of the hematopoietic system. By only viewing a series of 2-D projections, the high-dimensional nature of the data is rarely exploited. In this paper we present a means of determining a low-dimensional projection which maintains the high-dimensional relationships (i.e., information distance) between differing oncological data sets. By using machine learning techniques, we allow clinicians to visualize data in a low dimension defined by a linear combination of all of the available markers, rather than just two at a time. This provides an aid in diagnosing similar forms of cancer, as well as a means for variable selection in exploratory flow-cytometric research. We refer to our method as information preserving component analysis (IPCA).

The Brain Transcription Factor OTX1 Is Activated in Specific Non-Hodgkin Lymphoma Subtypes and Normally Expressed in a Germinal Center-Restricted Small Subpopulation of CD138+ Plasmacell-Like Cells.

OTX1 and OTX2 are transcription factors containing a bicoid-like homeodomain and play crucial roles in brain development and in few other body districts as in the case of OTX1, which is required in hematopoiesis for development of the erythroid compartment. Previous studies indicated that in human OTX2 is functionally involved in the generation of anaplastic medulloblastomas; OTX1 expression strongly correlates with nodular/desmoplastic medulloblastomas; and none of them is expressed in other brain tumors. Here we have investigated whether OTX1 and/or OTX2 may potentially be involved in tumors of nonneural origin by focusing on human B-cell non-Hodgkin's lymphomas (NHLs). We analyzed 184 cases (fig 1)encompassing different NHL subtypes according to the World Health Organization classification and discovered that, while OTX2 expression was never detected, OTX1 was selectively activated in virtually all cases of Diffuse Large B Cell Lymphoma, Burkitt Lymphoma and a relevant fraction of Follicular Cell Lymphomas. In DLBCL lymph nodes and tissue infiltrations, OTX1 protein was detected in the nucleus of PAX5+-CD20+ cancer cells. Conversely, in nonmalignant lymph nodes and tonsils, OTX1 was expressed in a numerically very small and non-proliferating cell population restricted to the germinal center. These OTX1+ cells were CD138+-IgG+, about 50% of them also co-expressed both CD10 and CD20 and none of them exhibited PAX5 or BCL6 expression, thus suggesting that OTX1 expression identifies a subset of GC-restricted plasmacell-like cells (fig 2). Interestingly, in contrast with lymphomas, in these cells the OTX1 protein was prevalently localized to the cytoplasm. Collectively, our data suggest that activation of OTX1 expression and its nuclear localization represent together a newly described molecular event occurring in specific NHL subtypes of GC and early post-GC origin (FCL, DLBCL, BL), and lead us to hypothesize that it may be potentially involved (directly or indirectly) in the initiation and/or maintenance of these tumors. [Display omitted] [Display omitted]

Environmental and Behavioral Factors and the Risk of Non-Hodgkin Lymphoma

Investigators around the world have reported that incidence and mortality rates for non-Hodgkin lymphoma (NHL) increased steadily and substantially over the last five decades of the 20th century. Identifying what changes in the environment or in behavior fueled this epidemic still presents a major

Global DNA methylation profiling reveals silencing of a secreted form of Epha7 in mouse and human germinal center B-cell lymphomas

Most human lymphomas originate from transformed germinal center (GC) B lymphocytes. While activating mutations and translocations of MYC, BCL2 and BCL6 promote specific GC lymphoma subtypes, other genetic and epigenetic modifications that contribute to malignant progression in the GC remain poorly defined. Recently, aberrant expression of the TCL1 proto-oncogene was identified in major GC lymphoma subtypes. TCL1 transgenic mice offer unique models of both aggressive GC and marginal zone B-cell lymphomas, further supporting a role for TCL1 in B-cell transformation. Here, restriction landmark genomic scanning was employed to discover tumor-associated epigenetic alterations in malignant GC and marginal zone B-cells in TCL1 transgenic mice. Multiple genes were identified that underwent DNA hypermethylation and decreased expression in TCL1 transgenic tumors. Further, we identified a secreted isoform of EPHA7, a member of the Eph family of receptor tyrosine kinases that are able to influence tumor invasiveness, metastasis and neovascularization. EPHA7 was hypermethylated and repressed in both mouse and human GC B-cell non-Hodgkin lymphomas, with the potential to influence tumor progression and spread. These data provide the first set of hypermethylated genes with the potential to complement TCL1-mediated GC B-cell transformation and spread.

Malignant Lymphomas in Autoimmunity and Inflammation: A Review of Risks, Risk Factors, and Lymphoma Characteristics

Certain autoimmune and chronic inflammatory conditions, such as Sjögren's syndrome and rheumatoid arthritis (RA), have consistently been associated with an increased risk of malignant lymphomas, but it is unclear whether elevated lymphoma risk is a phenomenon that accompanies inflammatory conditions in general. Likewise, it is debated whether the increased risk identified in association with some disorders pertains equally to all individuals or whether it varies among groups of patients with different phenotypic or treatment-related characteristics. It is similarly unclear to what extent the increased lymphoma occurrence is mediated through specific lymphoma subtypes. This update reviews the many findings on risks, risk levels, and lymphoma characteristics that have been presented recently in relation to a broad range of chronic inflammatory, including autoimmune, conditions. Recent results clearly indicate an association between severity of chronic inflammation and lymphoma risk in RA and Sjögren's syndrome. Thus, the average risk of lymphoma in RA may be composed of a markedly increased risk in those with most severe disease and little or no increase in those with mild or moderate disease. The roles of immunosuppressive therapy and EBV infection seem to be limited. Furthermore, RA, Sjögren's syndrome, systemic lupus erythematosus, and possibly celiac disease may share an association with risk of diffuse large B-cell lymphoma, in addition to well-established links of Sjögren's syndrome with risk of mucosa-associated lymphoid tissue lymphoma and of celiac disease with risk of small intestinal lymphoma. However, there is also obvious heterogeneity in risk and risk mediators among different inflammatory diseases.

Hepatitis C and Risk of Lymphoma: Results of the European Multicenter Case-Control Study EPILYMPH

Increasing evidence points toward a role of hepatitis C virus (HCV) infection in the etiology of malignant lymphomas. However, previous epidemiologic studies were limited in size to establish an association between HCV infection and specific lymphoma subtypes. We performed a large, multicenter, case-control study to address this question. The study comprised 5 European countries and included newly diagnosed cases of any lymphoid malignancy recruited between 1998 and 2004. Controls were matched to cases by 5-year age group, sex, and study center. In-person interviews were conducted to collect data on demographic, medical, and family history as well as environmental exposures. Serum samples of 1807 cases and 1788 controls (excluding human immunodeficiency virus-positive and organ-transplantation subjects) were screened for HCV infection using an enzyme immunoassay. Positive as well as randomly selected negative samples were subjected to HCV RNA detection and HCV genotyping. HCV infection was detected in 53 (2.9%) lymphoma cases and in 41 (2.3%) control subjects (odds ratio [OR], 1.42; 95% confidence interval [CI]: 0.93-2.15). Restricted to individuals who tested positive for HCV-RNA (indicating persistent infection and active viral replication), the OR was 1.82 (95% CI: 1.13-2.91). In subtype-specific analyses, HCV prevalence was associated with diffuse large B-cell lymphoma (OR, 2.19; 95% CI: 1.23-3.91) but not with chronic lymphocytic leukemia or follicular, Hodgkin's, or T-cell lymphoma. The sample size was not sufficient to derive any conclusions for rare lymphoma entities such as splenic marginal zone lymphoma. These results support a model that chronic HCV replication contributes to lymphomagenesis and establish a specific role of HCV infection in the pathogenesis of diffuse large B-cell lymphoma.

Gene arrays in lymphoma: Where will they fit in?

Molecular diagnostics for lymphoid malignancies has undergone substantial technical evolution during the past two decades, moving from labor-intensive investigations of individual abnormalities to high-throughput genome-wide analyses. Accordingly, its role has expanded to new fields such as monitoring of minimal residual disease and, more recently, outcome prediction in specific lymphoma subtypes. One novel technology that has had a major impact on the molecular diagnosis of lymphoid malignancies is gene expression profiling by DNA microarrays. It has provided robust and distinct molecular signatures for the most common types of lymphomas and has identified novel subsets that would not be identified by conventional methods. It also has led to the construction of molecularly defined prognostic models in these lymphoma subtypes and to a better understanding of the molecular mechanisms of lymphomagenesis. This development will undoubtedly transform diagnostic medicine in the near future and lead us into an era when tumor diagnosis will incorporate the information of critical molecular abnormalities that will have significant impact on disease outcome in each individual tumor sample. Future treatments are likely to be founded on effective, individualized, and mechanism-based therapies with the least toxicity.

Serous effusions in malignant lymphomas: A review

Serous effusions are a common complication of lymphomas. Although the frequency of pleural effusion is 20-30% in non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD), the involvement of peritoneal and pericardial cavities is uncommon. Among lymphoma subtypes, T-cell neoplasms, especially the lymphoblastic lymphomas, more frequently involve the serous fluids. The thoracic duct obstruction and impaired lymphatic drainage appear to be the primary mechanism for pathogenesis of pleural effusion in HD and direct pleural infiltration is the predominant cause in NHL. There is wide variation in rate of positive cytologic findings of NHL in pleural effusion (22.2-94.1%). Cytologic features of specific lymphoma subtypes such as lymphoblastic lymphoma, follicular center cell lymphoma, including Burkitt-type lymphoma, marginal zone lymphoma, MALT lymphoma, and anaplastic large-cell lymphoma, etc., have been described in the literature. The differential diagnostic problems of lymphomas in serous effusions include reactive lymphocytoses, early involvement by lymphomatous process, small round-cell tumors (SRCT), and presence of look-alike of Reed-Sternberg cells. To overcome these difficulties, various ancillary studies, including immunocytochemistry (ICC), morphometry, flow cytometry (FCM), and cytogenetics/molecular genetics (PCR, in-situ hybridization, and Southern blotting), have been performed on effusion specimens. ICC not only distinguishes lymphomas from reactive lymphocytoses and SRCTs, it significantly modifies the morphologic diagnosis to achieve a better classification of lymphomas. Combined morphology and immunophenotyping by FCM, has a sensitivity as well as specificity of 100%. Morphometry also distinguishes reactive lymphocytoses from malignant lymphoma with a high degree of sensitivity (>85%) and specificity (>95%). Limitations of individual ancillary techniques can be overcome by using multiple parameters. Although lymphomas rarely present as serous effusions without the involvement of other thoracic and extrathoracic sites, a small group of lymphomas called primary effusion lymphomas (PEL) exhibit exclusive or dominant involvement of serous cavities, without a detectable solid tumor mass. This body cavity based lymphoma (BCBL) is a distinct clinicopathologic entity and is found predominantly in AIDS patients with preexisting Kaposi sarcoma. In the absence of obstructive or infiltrative tumor mass, its pathogenesis has been attributed to stimulation by vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF), leading to vascular leakage. Cytomorphologically, PEL is usually a large-cell lymphoma, which appears to bridge features of large-cell immunoblastic and anaplastic large-cell lymphoma (ALCL). Most of these cases comprise a unique subgroup of B-cell lymphoma, with features of both high-grade anaplastic and B-immunoblastic lymphoma, but T-cell and/or natural killer cell immunophenotypes are described. Its association with various viral DNAs has been studied in detail by molecular techniques. Pleural effusion due to lymphomas, either primary or otherwise, is considered as one of the factors adversely influencing overall survival. The presence of pleural effusion at the time of presentation is not only associated with extremely poor outcome of lymphomas, it is also a predictor of disease relapse after chemotherapy and decreased survival. When the patients of lymphomatous pleural effusions with and without mediastinal mass present in respiratory distress, thoracocentesis is the initial diagnostic and therapeutic choice in these patients. In such situations, cytology along with ancillary studies not only gives a quick diagnosis of lymphoma, but also offers prognostically significant information such as classification of lymphomas, its grade and immunophenotype, and presence/absence of viral DNAs and tumor lysis syndrome.

Hepatitis C Virus Infection and B-Cell Non-Hodgkin's Lymphoma.

Backgroud: An increasing number of bacterial and viral infections have been linked with specific subtypes of lymphoma. Preliminary evidence suggests that hepatitis C virus (HCV) might play a pathogenetic role in autoimmune-related, non-malignant B-cell lymphoproliferation, as well as a subset of B-cell non-Hodgkin, s lymphomas (B-NHL), often with extranodal localization. Design and methods: The study was conducted in the Department of Hematology and consisted 149 (86 male, 63 female) untreated patients with a new diagnosis of B-NHL for 5-years period (2000–2004). HCV infection was investigated by testing for HCV antibodies in serum samples. The controls were 587 patients (without intravenous drug users) in other departments of the same hospital. Results: HCV infection was documented in 13 cases (8,4%) with NHL. The infected patients were not clinically relevant cryoglobulinemic activity, increased rate of autoimmune disorders and extranodal localizations prevalence. There was statistically significant difference between the NHL and control group (p<0,01) and no statistically significant difference between man/women carriers (p>0,05) into the NHL group. Overall, the clinical outcome of HCV-positive NHL does not seem to be different from that of NHL patients without HCV infection. However, the evidence of a significant liver injury may predict a worse prognosis in these cases. Conclusions: Our date suggest that HCV infection may be associated with B-NHL. With regard to the mechanism(s) by which HCV might favor B-cell expansion and malignant transformation, most date support an indirect pathogenetic role of the virus as an exogenous trigger. A direct oncogenetic role of HCV by direct cell infection and deregulation has only been hypothesized on the basis of the lymphotropism of the virus.

Histological Subtypes of Canine Lymphoma are Characterized by Unique Gene Expression Profiles

Introduction: In people, specific histological subtypes of lymphoma have different biological behaviors. Similar differences are recognized for some subtypes of canine lymphoma. Recently, microarray expression analysis has been used to identify unique gene expression profiles that characterize specific subtypes of human lymphoma. In this study, we use high‐density oligonucleotide microarrays to classify canine lymphomas based upon their gene expression profiles.Methods: Total RNA was isolated from 27 lymphoma and 3 normal lymph node canine biopsy samples. Microarray analysis was performed as described (http://www.dnaarrays.org). cRNA was hybridized to GeneChip® Canine Genome Arrays (Affymetrix), that contain over 21,700 probe sets, measuring transcripts across the entire canine genome. Gene expression levels were estimated from GeneChip® PM probe intensities by means of an enhanced version of the Li‐Wong PM‐only algorithm. Exceptional micro‐clusters of gene expression profiles were identified by means of a custom “agglomerative partitioning” algorithm which recursively partitions sets of gene expression profiles into a hierarchy (KTree) of “typical”(largest) and “exceptional”(smaller) subsets.Results: We identified microclusters of gene expression profiles that distinguish normal lymph node, B‐cell lymphoma, T‐cell lymphoma, and diffuse large B‐cell lymphoma phenotypes. We confirmed that, when standard hierarchical cluster analysis is applied to the identified gene expression profiles, tumors consistently cluster in concordance with their histological diagnosis.Conclusions: Histologically defined subtypes of canine lymphoma are characterized by distinct gene expression profiles. Gene expression profiling has great potential for the identification and verification of histological subtypes of lymphoma and for increasing understanding of the molecular pathology of canine lymphoma.

Autologous Peripheral Blood Stem Cell Transplant for Relapsed or Refractory T-Cell Non-Hodgkin's Lymphoma Results in Inferior Long Term Survival when Compared to Relapsed or Refractory B-Cell Non-Hodgkin's Lymphomas.

Autologous transplant has emerged as the standard of care for the treatment of relapsed B-cell non-Hodgkin's lymphomas (NHL). However, for the treatment of T-cell NHL, the role is not as clear. We report our experience with 24 patients with T-cell NHL who underwent autologous transplantation at time of first relapse. Lymphoma types were varied (peripheral T-cell = 8, lymphoblastic = 6, anaplastic large cell = 5, not otherwise specified = 5). All patients received CHOP as primary therapy, except one patient who received ProMACE/CytaBOM, one who received Stanford V, and two who received HyperCVAD. Patients had either relapsed disease (14 patients) or primary refractory disease (9 patients). One patient underwent autologous transplant as consolidation therapy. Mobilization regimens varied, consisting of dexamethasone, ifosphamide, etoposide, and cisplatin (DICE, 12 patients), dose intensive cyclophosphamide, etoposide, cisplatin (DICEP, 5 patients), cyclophosphamide/etoposide (3 patients), cyclophosphamide (2 patients), or other regimens (2 patients). Adequate collection of stem cells was seen in all but one case, which required bone marrow collection. The conditioning regimen used was BVAC (BCNU 600 mg/m2, etoposide 1600 mg/m2, cytarabine 24 g/m2, and cyclophosphamide 90 mg/kg) in 23 patients. One patient received melphalan conditioning. For the entire group, the overall survival at 3 years was 50%. This compares favorably with 336 relapsed B-cell NHL patients who underwent autologous transplant with the identical conditioning regimen (BVAC) in the same period of time (OS = 52%). At 5 years, the overall survival of the B-cell lymphoma group was stable at 49%. However, the overall survival for the T-cell NHL group declined to 30%. The primary cause of death post transplant was disease relapse. When divided among specific lymphoma subtypes, 3 of 8 patients with peripheral T-cell lymphoma, 4 of 5 patients with anaplastic large cell lymphoma, 3 of 6 patients with lymphoblastic lymphoma and 3 of 5 patients with other T-cell lymphoma subtypes remain alive. Although there are too few patients to draw any definite conclusions, it appears that autologous stem cell transplant for relapsed or refractory T-cell NHL results in similar 3-year overall survivals when compared to B-cell NHL using the same conditioning regimen. However, T-cell NHL appear to be associated with a higher late relapse rate which is reflected in the lower overall survivals at 5 years. Although there may be a benefit to autologous transplant in relapsed anaplastic large cell lymphomas, relapsed/refractory T-cell NHL had inferior long term overall survival compared to their B-cell counterpart transplanted with the same regimen. Novel approaches should be considered in the treatment of relapsed or refractory T-cell NHL.

Cutaneous T-cell lymphoma and atopy: is there an association?

Case reports have suggested a relationship between atopic diatheses and Sézary syndrome, pre-Sézary syndrome or mycosis fungoides. However, Sézary and pre-Sézary syndromes are rare entities, and this association has never been analysed in greater detail for specific subtypes of cutaneous T-cell lymphoma (CTCL). To evaluate the prevalence of atopy in subjects with Sézary syndrome, pre-Sézary syndrome or mycosis fungoides, and to compare the rates with the reported prevalence of atopy in the general population. We retrospectively reviewed the records of 157 patients with the diagnosis of Sézary or pre-Sézary syndrome seen between 1965 and 2000, and 102 patients with the diagnosis of mycosis fungoides evaluated from 1994 to 2000 at Mayo Clinic. Of 157 subjects with Sézary or pre-Sézary syndrome and 102 subjects with mycosis fungoides, 18 and 12, respectively, were identified as having a history of atopic dermatitis, asthma or allergic rhinitis. The prevalence rates of atopy in Sézary or pre-Sézary syndrome and mycosis fungoides were 11.5% (95% confidence interval 6.9-17.5%) and 11.8% (6.2-19.7%), respectively. No significant difference exists in the prevalence of atopy in Sézary or pre-Sézary syndrome compared with that in mycosis fungoides (chi2-test, P = 1.00). Furthermore, the rates of atopy in Sézary or pre-Sézary syndrome and mycosis fungoides are not significantly different from the prevalence of atopy in the general population (17-40%). On the basis of these observations, no evidence currently implicates a causal association of CTCL with atopy.

Lymphoma subtypes in patients with rheumatoid arthritis: increased proportion of diffuse large B cell lymphoma.

Patients with rheumatoid arthritis (RA) have an increased risk of developing malignant lymphoma. It is not clear whether the increase is confined to certain subtypes of lymphomas. Immunosuppressive therapy and Epstein-Barr virus (EBV) have been linked to the development of these lymphomas. To gain information about the baseline pattern of lymphoma subtypes in RA before the current widespread use of immunosuppressive drugs, we examined the distribution of lymphoma subtypes and the presence of EBV in a cohort of RA patients with a low frequency and duration of treatment with immunosuppressive drugs. By linking data from the Swedish Hospital Discharge Register and the Swedish Cancer Register, 42 cases of lymphoma were identified among 11683 patients with RA in the Uppsala Health Care Region between 1964 and 1984. The medical records and paraffin-embedded lymphoma tissues were collected, and the lymphomas were reclassified using the World Health Organization classification. In situ hybridization was used to detect EBV. Tissues from 35 patients were reviewed. Non-Hodgkin's lymphoma (NHL) was found in 33 patients and Hodgkin's lymphoma in 2 patients. There was an increased frequency of diffuse large B cell lymphoma (DLBCL) (22 of 33 NHL patients, 67%) compared with that in the general population (30-40%). EBV was detected in 5 of 30 examined lymphomas from patients (17%). Twenty of the 22 DLBCL patients had RA with medium or high inflammatory activity, and 6 had been treated with a disease-modifying antirheumatic drug for >or=1 year. The findings of this study suggest an increased incidence of one specific lymphoma subtype, DLBCL, in RA patients, as well as a possible association with RA disease activity.

Expression pattern of T-cell–associated chemokine receptors and their chemokines correlates with specific subtypes of T-cell non-Hodgkin lymphoma

AbstractChemokine receptors mediate the migration of lymphocytes through the binding of soluble ligands, and their expression is differentially regulated in lymphocyte subsets. The pattern of chemokine receptor expression in T-cell non-Hodgkin lymphoma has not been previously studied. Using a panel of mouse monoclonal antibodies, we studied the immunohistochemical expression of the Th1-associated chemokine receptor CXCR3 in 141 patients with T-cell lymphoma, and we studied the receptors CCR4 and CCR5 and some of their ligands in a subset of these tumors. Expression of CXCR3 was typical of the smaller T cells in angioimmunoblastic lymphoma (15 of 18 patients), angiocentric lymphoma (3 of 3 patients), histiocyte-rich tumors (4 of 5 patients), and unspecified T-cell lymphomas (17 of 39 patients). CXCR3 expression was seen in only 1 of 15 patients with anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma. In contrast, all ALK-positive tumors showed diffuse reactivity for the Th2-associated receptor CCR4 (5 of 5 patients). CCR4 expression was also a consistent feature of the large-cell transformation of mycosis fungoides. CCR5 expression showed no consistent association with any T-cell tumor type. The chemokines Mig (CXCR3 ligand), TARC (CCR4 ligand), and MCP-2 (CCR5 ligand) were detected in intratumoral blood vessels and histiocytes. Mig was also coexpressed by a subset of CXCR3-positive tumor cells in 6 of 20 lymphomas. MCP-2 was highly expressed in stromal cells in 3 patients with nodal involvement by cutaneous T-cell lymphoma. As with normal T-cell subsets, we demonstrated that there is frequent differential expression of chemokine receptors in T-cell tumors, which may explain, in part, the distinctive patterns of spread in different tumor subtypes.

Expression pattern of T-cell–associated chemokine receptors and their chemokines correlates with specific subtypes of T-cell non-Hodgkin lymphoma

Chemokine receptors mediate the migration of lymphocytes through the binding of soluble ligands, and their expression is differentially regulated in lymphocyte subsets. The pattern of chemokine receptor expression in T-cell non-Hodgkin lymphoma has not been previously studied. Using a panel of mouse monoclonal antibodies, we studied the immunohistochemical expression of the Th1-associated chemokine receptor CXCR3 in 141 patients with T-cell lymphoma, and we studied the receptors CCR4 and CCR5 and some of their ligands in a subset of these tumors. Expression of CXCR3 was typical of the smaller T cells in angioimmunoblastic lymphoma (15 of 18 patients), angiocentric lymphoma (3 of 3 patients), histiocyte-rich tumors (4 of 5 patients), and unspecified T-cell lymphomas (17 of 39 patients). CXCR3 expression was seen in only 1 of 15 patients with anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma. In contrast, all ALK-positive tumors showed diffuse reactivity for the Th2-associated receptor CCR4 (5 of 5 patients). CCR4 expression was also a consistent feature of the large-cell transformation of mycosis fungoides. CCR5 expression showed no consistent association with any T-cell tumor type. The chemokines Mig (CXCR3 ligand), TARC (CCR4 ligand), and MCP-2 (CCR5 ligand) were detected in intratumoral blood vessels and histiocytes. Mig was also coexpressed by a subset of CXCR3-positive tumor cells in 6 of 20 lymphomas. MCP-2 was highly expressed in stromal cells in 3 patients with nodal involvement by cutaneous T-cell lymphoma. As with normal T-cell subsets, we demonstrated that there is frequent differential expression of chemokine receptors in T-cell tumors, which may explain, in part, the distinctive patterns of spread in different tumor subtypes.

Historical review of lymphomas.

Historical review of lymphomas.

Molecular Epidemiology of EBNA-1 Substrains of Epstein-Barr Virus in Posttransplant Lymphoproliferative Disorders Which Have Infrequent p53 Mutations

Posttransplant lymphoproliferative disorders (PTLDs), which are highly associated with Epstein-Barr virus infection, have a low frequency of molecular genetic abnormalities. Recently it has been suggested certain EBV substrains may be associated with specific lymphoma subtypes. The goals of our study were two fold: 1) to determine the prevalence of EBNA-1 substrains and prognostic utility in PTLD and 2) to determine the incidence of p53 gene mutations and p53 protein overexpression in 32 EBV-positive PTLD cases. Tumor DNA was sequenced to identify EBNA-1 substrains at codon 487 and p53 gene mutations in exons 5-8. The PTLD samples contained the following EBNA-1 substrains: P-thr in 17/32 (53%), P-ala in 11/32 (34%), and V-leu in 4/32 (13%). More heterogeneity within major subtypes was seen in the PTLD cases than in the referral group. A second group of 25 referral (non-PTLD) samples including infectious mononucleosis (6) and sequential EBV positive virology samples (19) contained P-thr in 17/25 (68%); P-ala in 2/25 (8%); and V-leu in 6/25 (24%). In the 29 B-cell PTLD the time to presentation was an average of 13.3 months in the P-ala group, 16.6 months in the P-thr group, and 40.6 months in the V-leu group: (p>0.05). There was no difference in survival in patients (median overall - 60 months) between the three different substrains of EBNA-1 (Log rank test, p=0.39). One of 31 (4.1%) cases (a diffuse large cell B-cell) had a p53 mutation. Seven of 31 (23%) cases (all B-cell), including the p53 mutated case, had over-expression of p53 protein. We conclude EBNA-1 substrains vary in PTLD and suggest the pattern reflects the geographical incidence of substrains in the region. We also conclude p53 mutations are not a significant molecular genetic abnormality in PTLD.