Novel developments in the pathogenesis and diagnosis of extranodal marginal zone lymphoma

Extranodal marginal zone lymphoma (EMZL), mostly represented by mucosa-associated lymphoid tissue (MALT) type, also referred to as MALT lymphoma, is a clinically heterogeneous entity within the group of low-grade B cell lymphomas that arises in a wide range of different extranodal sites, including the stomach, lung, ocular adnexa, and skin. It represents the third most common non-Hodgkin lymphoma in the Western world, and the median age of occurrence is around 60 years. One characteristic aspect in a subset of EMZL detectable in about 25% of the cases is the presence of specific chromosomal translocations involving the genes MALT1 and BCL10, which lead to activation of the NF-κB signaling pathway. Another unique aspect is that several infectious agents, such as Helicobacter pylori in the case of gastric EMZL, and autoimmune disorders, like Sjögren syndrome, have been implicated in the pathogenesis of this cancer. Recent findings as summarized in this review have further improved our understanding of the complex pathobiology of this disease and have been essential to better define novel treatment strategies. In addition, many of these specific features are currently being implemented for the diagnosis of EMZL.

Recurrent mutations in genes involved in nuclear factor-κB signalling in nodal marginal zone lymphoma-diagnostic and therapeutic implications

AIMS

To investigate the spectrum of mutations in 20 genes involved in B-cell receptor and/or Toll-like receptor signalling resulting in activation of nuclear factor-κB (NF-κB) in 20 nodal marginal zone lymphomas (NMZLs), 20 follicular lymphomas (FLs), and 11 cases of B-cell lymphoma, unclassifiable (BCL-u).

METHODS AND RESULTS

Nodal marginal zone lymphomas were diagnosed according to strict criteria, including the expression of at least one putative marginal zone marker (MNDA and/or IRTA1). Cases that showed features of NMZL but did not fulfil all criteria were included as BCL-u. All FLs were required to have a BCL2 rearrangement. Mutations were found in: nine NMZLs, with recurrent mutations in TNFAIP3 and CD79B; 12 FLs, with recurrent mutations in TNFRSF14, TNFAIP3, and CARD11; and five cases of BCL-u, with recurrent mutations in TNFRSF14. TNFRSF14 mutations were present in FL and BCL-u, but not in any of the NMZLs. In the BCL-u group, TNFRSF14 mutations clustered with a FL immunophenotype.

CONCLUSIONS

These results suggest that TNFRSF14 mutations point towards a diagnosis of FL, and can be used in the sometimes difficult distinction between NMZL and FL, but to apply this in diagnostics would require confirmation in an independent cohort. In addition, the presence or absence of specific mutations in pathways converging on NF-κB could be important for decisions regarding targeted treatment.

Tetraspanin CD37 protects against the development of B cell lymphoma

Worldwide, B cell non-Hodgkin lymphoma is the most common hematological malignancy and represents a substantial clinical problem. The molecular events that lead to B cell lymphoma are only partially defined. Here, we have provided evidence that deficiency of tetraspanin superfamily member CD37, which is important for B cell function, induces the development of B cell lymphoma. Mice lacking CD37 developed germinal center-derived B cell lymphoma in lymph nodes and spleens with a higher incidence than Bcl2 transgenic mice. We discovered that CD37 interacts with suppressor of cytokine signaling 3 (SOCS3); therefore, absence of CD37 drives tumor development through constitutive activation of the IL-6 signaling pathway. Moreover, animals deficient for both Cd37 and Il6 were fully protected against lymphoma development, confirming the involvement of the IL-6 pathway in driving tumorigenesis. Loss of CD37 on neoplastic cells in patients with diffuse large B cell lymphoma (DLBCL) directly correlated with activation of the IL-6 signaling pathway and with worse progression-free and overall survival. Together, this study identifies CD37 as a tumor suppressor that directly protects against B cell lymphomagenesis and provides a strong rationale for blocking the IL-6 pathway in patients with CD37- B cell malignancies as a possible therapeutic intervention.

A 20-year population-based study on the epidemiology, clinical features, treatment, and outcome of nodular lymphocyte predominant Hodgkin lymphoma

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a subtype of Hodgkin lymphoma characterized by a unique clinical and histological presentation. Because of the rare nature of this disease, few large-scale studies are available. We conducted a cohort study in which patients were identified in the Netherlands Cancer Registry in the Southeast of the Netherlands between 1990 and 2010. Of these patients, we collected all clinical characteristics and re-reviewed pathologic material to confirm NLPHL diagnosis. Seventy-three histologically confirmed cases of NLPHL were analyzed with a median follow-up of 65 months (range 4–257 months). Median age at diagnosis was 43 years (range 1–87); 84.9 % of the patients were male; B symptoms were present in 5.5 %; and stage I/II disease was most common (75.4 %). Patients were primarily treated with radiotherapy (50.7 %), chemotherapy (26 %), combined modality (radiotherapy and chemotherapy) (11 %), or surgical excision with careful watch-and-wait (12.3 %). Relapses occurred in seven patients (9.6 %) after a median of 26 months (21–74 months). Six patients (8.2 %) developed histologic transformation to large cell lymphoma. Five patients (6.8 %) died during follow-up due to progression of NLPHL (n = 1), histologic transformation (n = 2) and intercurrent deaths (n = 2). The estimated 10-year overall survival was 94.0 % and the 10-year progression-free survival 75.8 %. Our study confirms the distinct characteristics of NLPHL with a relatively good long-term prognosis. It may be possible to reduce treatment intensity in early stage NLPHL without affecting long-term outcome.

Microarray-based genomic profiling and in situ hybridization on fibrotic bone marrow biopsies for the identification of numerical chromosomal abnormalities in myelodysplastic syndrome

Background

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematological malignancies. In MDS patients with a fibrotic bone marrow the aspiration of cells often fails (dry-tap), which hampers standard karyotyping. Obtaining genetic data from these fibrotic marrows is therefore challenging, and up till now in situ hybridization applied to bone marrow biopsies is the only option. The microarray-based genomic profiling technology has already proven its value for bone marrow aspirates and peripheral blood samples, but has never been applied to the technically challenging bone marrow biopsies. We describe an approach for microarray-based genomic profiling on bone marrow biopsies and demonstrate its ability to obtain clinically relevant cytogenetic aberrations. In addition the data were compared with those obtained by in situ hybridization and karyotyping.

Results

We have evaluated the success rate of microarray-based genomic profiling by studying twenty-one bone marrow biopsies (7 fibrotic MDS, 12 non-fibrotic MDS and 2 reactive), by microarray-based genomic profiling and in situ hybridization (12 of 21 cases). The data obtained with these techniques were compared with conventional karyotyping data on corresponding bone marrow aspirates. Of the 15 copy number aberrations that were detected by in situ hybridization, 13 were concordant with microarray-based genomic profiling and karyotyping, whereas two hybridizations were misinterpreted. In 20 of 21 patients, the data obtained by microarray-based genomic profiling and karyotyping were identical or differences could be explained by the presence of marker chromosomes, complex karyotypes, clonal heterogeneity or disease progression.

Conclusions

We demonstrate that genome wide microarray-based genomic profiling performed on bone marrow biopsies has a similar success rate compared to in situ hybridization, and prevents misinterpretation of chromosomal losses as observed by FISH. In addition, equal to even higher resolutions were obtained with genomic profiling compared to conventional karyotyping. Our findings indicate that microarray-based profiling, even on bone marrow biopsies, is a valid approach for the identification of genetic abnormalities. This is a valuable substitution in cases of fibrotic MDS lacking cytogenetic results.

Abundance of IgG4+ plasma cells in isolated reactive lymphadenopathy is no indication of IgG4-related disease

OBJECTIVES

IgG4-related disease is a recently recognized condition that can be associated with lymphadenopathy, with several histologic patterns and increased absolute number and ratio of immunoglobulin G4 (IgG4)-positive plasma cells. However, these findings are considered to be not exclusively specific for IgG4-related disease.

METHODS

The occurrence of the histologic patterns reported in patients with isolated lymphadenopathy was studied and correlated with the clinical presentation to determine their predictive value for IgG4-related lymphadenopathy.

RESULTS

We found cases meeting all histologic criteria for IgG4-related lymphadenopathy, without clinical signs of IgG4-related disease. The only pattern that was not seen in this series was an inflammatory pseudotumor-like picture.

CONCLUSION

Without a clinical suspicion of IgG4-related disease, these morphologic patterns and high numbers of IgG4-positive plasma cells should be interpreted with care to avoid an erroneous diagnosis of IgG4-related disease.

A dominant-negative GFI1B mutation in the gray platelet syndrome

The gray platelet syndrome is a hereditary, usually autosomal recessive bleeding disorder caused by a deficiency of alpha granules in platelets. We detected a nonsense mutation in the gene encoding the transcription factor GFI1B (growth factor independent 1B) that causes autosomal dominant gray platelet syndrome. Both gray platelets and megakaryocytes had abnormal marker expression. In addition, the megakaryocytes had dysplastic features, and they were abnormally distributed in the bone marrow. The GFI1B mutant protein inhibited nonmutant GFI1B transcriptional activity in a dominant-negative manner. Our studies show that GFI1B, in addition to being causally related to the gray platelet syndrome, is key to megakaryocyte and platelet development.

Evaluation of a panel of expert pathologists: review of the diagnosis and histological classification of Hodgkin and non-Hodgkin lymphomas in a population-based cancer registry

Abstract Correct histological classification of malignant lymphomas is important but has always been a difficult challenge. Since 2001 the World Health Organization (WHO) classification has been used, which should make it easier to define distinct disease entities. The purpose of this study was to evaluate the usefulness of a panel of expert hematopathologists in reviewing the diagnosis of malignant lymphomas and to examine whether the discordance between primary and panel diagnoses has declined throughout the years. All patients with a primary malignant lymphoma diagnosed between 2000-2001 and 2005-2006 were identified through the population based cancer registry. All diagnoses were reviewed by a panel of three expert pathologists. In 2000-2001, 344 patients were included, and in 2005-2006, 370 patients. The overall discordance rate decreased from 14% in 2000-2001 to 9% in 2005-2006 (p = 0.06). We were able to identify lymphoma subgroups with the highest discordance rates and lowest discordance rates (mantle cell lymphoma and classical Hodgkin lymphoma), which remained unchanged throughout the years. Based on these results we would propose to review all cases of malignant lymphoma with the exception of mantle cell lymphoma and classical Hodgkin lymphoma, when the initial pathologist has no doubt about the diagnosis.

Homing characteristics of donor T cells after experimental allogeneic bone marrow transplantation and posttransplantation therapy for multiple myeloma

Relapse and graft-versus-host disease remain major problems associated with allogeneic bone marrow (BM) transplantation (allo-BMT) and posttransplantation therapy in patients with multiple myeloma (MM) and other hematologic malignancies. A possible strategy for selectively enhancing the graft-versus-myeloma response and possibly reducing graft-versus-host disease is to increase the migration of alloreactive T cells toward the MM-containing BM. In the present study, we characterized the BM-homing behavior of donor-derived effector T cells in a novel allo-BMT model for the treatment of MM. We observed that posttransplantation immunotherapy consisting of donor lymphocyte infusion (DLI) and vaccination with minor histocompatibility antigen-loaded dendritic cells (DCs) was associated with prolonged survival compared with allo-BMT with no further treatment. Moreover, CD8(+) effector T cells expressing inflammatory homing receptors, including high levels of CD44, LFA-1, and inflammatory chemokine receptors, were recruited to MM-bearing BM. This was paralleled by strongly increased expression of IFN-γ and IFN-γ-inducible chemokines, including CXCL9, CXCL10, and CXCL16, especially in mice treated with DLI plus minor histocompatibility antigen-loaded DC vaccination. Remarkably, expression of the homeostatic chemokine CXCL12 was reduced. Furthermore, IFN-γ and TNF-α induced BM endothelial cells to express high levels of the inflammatory chemokines and reduced or unaltered levels of CXCL12. Finally, presentation of CXCL9 by multiple BM endothelial cell-expressed heparan sulfate proteoglycans triggered transendothelial migration of effector T cells. Taken together, our data demonstrate that both post-transplantation DLI plus miHA-loaded DC vaccination and MM growth result in an increased expression of inflammatory homing receptors on donor T cells, decreased levels of the homeostatic BM-homing chemokine CXCL12, and strong induction of inflammatory chemokines in the BM. Thus, along with increasing the population of alloreactive T cells, post-transplantation immunotherapy also might contribute to a more effective graft-versus-tumor response by switching homeostatic T cell migration to inflammation-driven migration.

Reproducibility of histologic classification in nonfibrotic myeloproliferative neoplasia

Early phases of polycythemia vera, essential thrombocythemia, and primary myelofibrosis (PMF) can be difficult to distinguish by morphologic studies alone because they share many morphologic characteristics. Histologic criteria according to the 2008 World Health Organization (WHO) classification are part of the myeloproliferative neoplasia (MPN) diagnosis. Our aim was to assess the reproducibility of morphologic characteristics and determine their relative importance for histologic diagnoses on selected trephine biopsy sections. For the study, 56 prefibrotic MPN trephine specimens were blindly reviewed by 4 hematopathologists using a scoring list of 16 histologic characteristics mentioned in the WHO classification. Consensus was defined as agreement by 3 of 4 hematopathologists. High degrees of consensus were reached for individual major morphologic features used in the WHO classification, especially for the nuclear features of megakaryocytes (83%). Some of the features correlated positively or negatively with the histologic diagnosis of PMF. Consensus for the histologic classification of MPN was reached in 39 (70%) of 56 cases without knowledge of clinical data. This finding indicates a difference in the relative importance assigned to individual histologic characteristics by different hematopathologists.

Biomarkers as disease definition: mantle cell lymphoma as an example

The introduction in pathology practice of a new biomarker that is contributing to define a disease requires a series of investigations. Now that new biomarkers are being discovered continuously it is important to learn from successful examples of markers that are presently widely used. In this historical account the steps are described that have led to the use of immunohistochemical staining of tissue samples with an antibody against cyclinD1 to diagnose mantle cell lymphoma. Furthermore, a short outlook is given on the introduction of proteomics as a tool in the diagnosis of lymphoma and the potential route to be taken for introducing this technology into clinical practice.

Young age and a positive family history of colorectal cancer are complementary selection criteria for the identification of Lynch syndrome

Families at high risk for Lynch syndrome can effectively be recognised by microsatellite instability (MSI) testing. The aim of the present study is to compare the effectiveness of a MSI test for the identification of Lynch syndrome in patients selected by a pathologist mainly based on young age at diagnosis (MSI-testing-indicated-by-a-Pathologist; MIPA), with that of patients selected by a clinical geneticist mainly based on family history (MSI-testing-indicated-by-Family-History; MIFH). Patients with a Lynch syndrome associated tumour were selected using MIPA (n=362) or MIFH (n=887). Germline DNA mutation testing was performed in 171 out of 215 patients (80%) with a MSI positive tumour. MSI was tested positive in 20% of the MIPA-group group compared to 16% in the MIFH-group (P=0.291). In 91 of 171 patients with MSI positive tumours tested for germline mutations were identified as Lynch syndrome patients: 42% in the MIPA-group and 56% in the MIFH-group (P=0.066). Colorectal cancer (CRC) or endometrial cancer (EC) presenting at an age below 50 years would have led to the diagnosis of Lynch syndrome in 89% of these families (CRC below 50 years: 88% and EC below 50 years: 12%). Families detected by MIPA were characterised more often by extracolonic Lynch syndrome associated malignancies, especially EC (P<0.001). Our results indicate that recognition of Lynch syndrome by CRC or EC below 50 years is as effective as a positive family history. Families from patients selected by individual criteria more often harbour extracolonic Lynch syndrome associated malignancies.

Protein profiling in pathology: analysis and evaluation of 239 frozen tissue biopsies for diagnosis of B-cell lymphomas

PURPOSE

We determined the potential value of protein profiling of tissue samples by assessing how precise this approach enables discrimination of B-cell lymphoma from reactive lymph nodes, and how well the profiles can be used for lymphoma classification.

EXPERIMENTAL DESIGN

Protein lysates from lymph nodes (n=239) from patients with the diagnosis of reactive hyperplasia (n=44), follicular lymphoma (n=63), diffuse large B-cell lymphoma (n=43), mantle cell lymphoma (n=47), and chronic lymphocytic leukemia/small lymphocytic B-cell lymphoma (n=42) were analysed by SELDI-TOF MS. Data analysis was performed by (i) classification and regression tree-based analysis and (ii) binary and polytomous logistic regression analysis.

RESULTS

After internal validation by the leave-one-out principle, both the classification and regression tree and logistic regression classification correctly identified the majority of the malignant (87 and 96%, respectively) and benign cases (73 and 75%, respectively). Classification was less successful since approximately one-third of the cases of each group were misclassified according to the histological classification. However, an additional mantle cell lymphoma case that was misclassified as chronic lymphocytic leukemia/small lymphocytic B-cell lymphoma initially was identified based on the protein profile.

CONCLUSIONS AND CLINICAL RELEVANCE

SELDI-TOF MS protein profiling allows for reliable identification of the majority of malignant lymphoma cases; however, further validation and testing robustness in a diagnostic setting is needed.

Changed concepts and definitions of myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) in the updated 2008 WHO classification

The purpose of this overview is to discuss the changes in the 2008 WHO classification of myeloid neoplasms, with exclusion of acute myeloid leukaemia. Specific mutations or rearrangements leading to constitutive activation of growth factor receptors or cytoplasmic tyrosine kinases are now recognised as recurrent genetic events characterising the group of myeloproliferative neoplasms (MPN). A newly introduced subgroup consists of patients with persistent eosinophilia and myeloid or lymphoid proliferations harbouring specific genetic changes involving platelet-derived growth factor receptors alpha and beta (PDGFRA and PDGFRB) or fibroblast growth factor receptor 1 (FGFR1). The clinical relevance of recognising myeloid neoplasms with aberrant tyrosine kinase activity is based in novel treatment options with tyrosine kinase inhibitors. The myelodysplastic syndromes (MDS) without increased blasts are further divided into subtypes of refractory cytopaenias with unilineage dysplasia. A new provisional entity is refractory cytopaenia of childhood. Down syndrome- and therapy-related myeloid neoplasms, including MDS, were moved to the section of acute myeloid leukaemia and related precursor neoplasms.

Heritable somatic methylation and inactivation of MSH2 in families with Lynch syndrome due to deletion of the 3' exons of TACSTD1

Lynch syndrome patients are susceptible to colorectal and endometrial cancers owing to inactivating germline mutations in mismatch repair genes, including MSH2 (ref. 1). Here we describe patients from Dutch and Chinese families with MSH2-deficient tumors carrying heterozygous germline deletions of the last exons of TACSTD1, a gene directly upstream of MSH2 encoding Ep-CAM. Due to these deletions, transcription of TACSTD1 extends into MSH2. The MSH2 promoter in cis with the deletion is methylated in Ep-CAM positive but not in Ep-CAM negative normal tissues, thus revealing a correlation between activity of the mutated TACSTD1 allele and epigenetic inactivation of the corresponding MSH2 allele. Gene silencing by transcriptional read-through of a neighboring gene in either sense, as demonstrated here, or antisense direction, could represent a general mutational mechanism. Depending on the expression pattern of the neighboring gene that lacks its normal polyadenylation signal, this may cause either generalized or mosaic patterns of epigenetic inactivation.