High BCL6 expression predicts better prognosis, independent of BCL6 translocation status, translocation partner, or BCL6-deregulating mutations, in gastric lymphoma

Ras interacting protein 1 facilitated proliferation and invasion of diffuse large B-cell lymphoma cells

A GTPase binding protein, Ras interacting protein 1 (RASIP1), has been reported with a tumor-promoting role in lung cancer cells, and its role in lymphoma remains unknown. The analysis of medical databank shows that RASIP1 is upregulated in diffuse large B-cell lymphoma (DLBCL) specimens. In this article, we demonstrated that RASIP1 is highly expressed in DLBCL cell lines, compared with primary B cells. The gain- and loss-of-function experiments were performed to investigate the effects of RASIP1 on DLBCL cells. CCK-8, flow cytometry, western blot, and transwell assays demonstrated that silence of RASIP1 inhibited proliferation, cell cycle transition, and invasion and induced significant apoptosis in DLBCL cells, and ectopic expression of RASIP1 played opposite roles. Xenograft results revealed that RASIP1 facilitated the growth of DLBCL cells in vivo. These findings suggest that RASIP1 may be required for malignancy of DLBCL cells. In addition, we also found that the expression of RASIP1 was negatively regulated by forkhead box O3 (FOXO3), which has been reported to suppress the proliferation of DLBCL cells. Our results indicate that FOXO3 is bound to the promoter sequence of RASIP1 and inhibits its transcription. The suppressive effects of FOXO3 on proliferation and invasion of DLBCL cells were neutralized by RASIP1. In conclusion, we demonstrate that FOXO3 negatively regulated RASIP1 facilitates growth and invasion of DLBCL cells, provides novel diagnostic markers and therapeutic targets for DLBCL in clinic.

Overexpression of BCL2, BCL6, VEGFR1 and TWIST1 in Circulating Tumor Cells Derived from Patients with DLBCL Decreases Event-Free Survival

Purpose

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous malignant lymphoid neoplasm and is the most common subtype of non-Hodgkin lymphoma in adults. More than half of patients with DLBCL can achieve remission with standard R-CHOP regimes; however, approximately 30-40% of patients are still failing this standard therapy, which remains as an important cause of progression and mortality of this disease. It is necessary to have diagnostic and monitoring tools that allow us to improve the accuracy of prognosis in these patients. Circulating tumor cells (CTCs) identification through molecular biomarkers is one of the novel strategies that have been used in other types of cancer, and we aim to use this tool to analyze the potential role in DLBCL.

Patients and Methods

We analyzed 138 blood samples of patients with DLBCL, of which CTCs were isolated by density gradient for subsequent detection and quantitation of molecular biomarkers using RT-qPCR with TaqMan probes. Survival analysis was performed using Kaplan-Meier curves.

Results

We found overexpression of ABCB1, αSMA, BCL2, BCL6 and VEGFR1 genes, as well as the presence of CK19, EpCAM, KI67, MAGE-A4, SNAIL and TWIST1 genes. CK19 and EpCAM expression were associated with a minor OS (85.7% vs 98.1%, p = 0.002). The overexpression of BCL2, BCL6, VEGFR1 and TWIST1 was related to a minor EFS (p = 0.001).

Conclusion

This study showed that in liquid biopsies analyzed, the presence of CTCs can be confirmed through molecular biomarkers, and it has an impact on OS and EFs, making this detection useful in the follow-up and prognosis of patients with DLBCL.

The Effect of the Tumor Microenvironment on Lymphoid Neoplasms Derived from B Cells

Lymphomas are characteristic tumors surrounded by an inflammatory microenvironment. The cells of the microenvironment are essential for the growth and survival of neoplastic cells and are recruited through the effect of cytokines/chemokines. Lymphomas include heterogeneous groups of neoplasms infiltrating various lymphoid structures which may arise from B lymphocytes, T lymphocytes, and natural killer (NK) cells at various stages of their differentiation state. In this review article, we analyze the literature data concerning the involvement of the tumor microenvironment (TME) in the progression of lymphomas and the recent advances in the analysis of microenvironment components in the most common forms: some mature B cell lymphoma neoplasms and classic Hodgkin lymphomas. The complex crosstalk between the TME and tumor cells led to the discovery of many mechanisms usable as molecular-targeted therapy through the control of diverse elements of the TME, varying from inhibitors of angiogenic cytokines and their receptors to the regulation of cells' activities and the novel immune checkpoint inhibitors.

Human rDNA and Cancer

In human cells, each rDNA unit consists of the ~13 kb long ribosomal part and ~30 kb long intergenic spacer (IGS). The ribosomal part, transcribed by RNA polymerase I (pol I), includes genes coding for 18S, 5.8S, and 28S RNAs of the ribosomal particles, as well as their four transcribed spacers. Being highly repetitive, intensively transcribed, and abundantly methylated, rDNA is a very fragile site of the genome, with high risk of instability leading to cancer. Multiple small mutations, considerable expansion or contraction of the rDNA locus, and abnormally enhanced pol I transcription are usual symptoms of transformation. Recently it was found that both IGS and the ribosomal part of the locus contain many functional/potentially functional regions producing non-coding RNAs, which participate in the pol I activity regulation, stress reactions, and development of the malignant phenotype. Thus, there are solid reasons to believe that rDNA locus plays crucial role in carcinogenesis. In this review we discuss the data concerning the human rDNA and its closely associated factors as both targets and drivers of the pathways essential for carcinogenesis. We also examine whether variability in the structure of the locus may be blamed for the malignant transformation. Additionally, we consider the prospects of therapy focused on the activity of rDNA.

Development and validation of prognostic scoring in primary intestinal diffuse large B-cell lymphoma: a single-institution study of 184 patients

Background

The incidence of primary intestinal diffuse large B-cell lymphoma (PI-DLBCL) is much lower than primary gastric DLBCL, and large-scale analyses on the clinical characteristics, molecular features, therapeutic strategies, and risk stratification have been seldomly performed in PI-DLBCL.

Methods

To assess prognostic model development, 107 PI-DLBCL patients diagnosed before 2014 were studied for prognosis factors including different primary involved sites and treatment strategies. For internal validation, a non-random split sample set with 77 PI-DLBCL patients after 2014 was included for validation of the prognosis factors.

Results

Patients with an ileocecal lesion presented with better survival time than those with non-ileocecal sites, with surgical resection significantly influencing the prognosis. Non-ileocecal patients who underwent surgery with lymphadenectomy had superior overall survival (OS) and progression-free survival (PFS) compared to those receiving surgery without lymphadenectomy or those not receiving (without) surgery. For ileocecal patients, surgery with or without lymphadenectomy resulted in better OS and PFS than those without surgery. For biomarker analysis, only BCL-2 >50% or Ki67 >80% on tumor cells indicated poor clinical outcome. In multivariate analysis, age, Eastern Cooperative Oncology Group (ECOG) score, and site of origin were independent prognostic factors for inferior OS in PI-DLBCL. A prognosis model was set up based on age, ECOG score, and site of origin, and validated well.

Conclusions

The prognosis in patients with PI-DLBCL with ileocecal involvement showed was better than those with non-ileocecal involvement. Surgical strategy can impact the clinical outcome of PI-DLBCL patients.

International Prognostic Index-Based Immune Prognostic Model for Diffuse Large B-Cell Lymphoma

Background

The International Prognostic Index (IPI) is widely used to discriminate the prognosis of patients with diffuse large B-cell lymphoma (DLBCL). However, there is a significant need to identify novel valuable biomarkers in the context of targeted therapy, such as immune checkpoint blockade (ICB).

Methods

Gene expression data and clinical DLBCL information were obtained from The Cancer Genome Atlas and Gene Expression Omnibus datasets. A total of 371 immune-related genes in DLBCL patients associated with different IPI risk groups were identified by weighted gene co-expression network analysis, and eight genes were selected to construct an IPI-based immune prognostic model (IPI-IPM). Subsequently, we analyzed the somatic mutation and transcription profiles of the IPI-IPM subgroups as well as the potential clinical response to immune checkpoint blockade (ICB) in IPI-IPM subgroups.

Results

The IPI-IPM was constructed based on the expression of CMBL, TLCD3B, SYNDIG1, ESM1, EPHA3, HUNK, PTX3, and IL12A, where high-risk patients had worse overall survival than low-risk patients, consistent with the results in the independent validation cohorts. The comprehensive results showed that high IPI-IPM risk scores were correlated with immune-related signaling pathways, high KMT2D and CD79B mutation rates, and upregulation of inhibitory immune checkpoints, including PD-L1, BTLA, and SIGLEC7, indicating a greater potential response to ICB therapy.

Conclusion

The IPI-IPM has independent prognostic significance for DLBCL patients, which provides an immunological perspective to elucidate the mechanisms of tumor progression and sheds light on the development of immunotherapy for DLBCL.

Update on B-cell lymphoproliferative disorders of the gastrointestinal tract

The gastrointestinal (GI) tract is home to a significant portion of the immune system, which interacts daily with the antigenic milieu of its contents. Therefore, the presence of white blood cells within the walls of the GI tract upon histologic examination is a familiar sight on GI biopsies-both in health and disease. The GI tract is the most common site of extranodal lymphomas, most of which are B-cell neoplasms. Here, we review common and uncommon B-cell neoplasms of the GI tract - extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), mantle cell lymphoma, duodenal-type follicular lymphoma, diffuse large B-cell lymphoma, plasmablastic lymphoma, EBV-positive mucocutaneous ulcer, and post-transplant lymphoproliferative disorders - with special focus on literature published during the past five years. Along with the other articles in this edition of Seminars in Diagnostic Pathology, it is the authors' hope that this review proves to be a useful resource in the workup of the array of hematopoietic processes that can involve the GI tract.

Recent advances upper gastrointestinal lymphomas: molecular updates and diagnostic implications

Approximately one-third of extranodal non-Hodgkin lymphomas involve the gastrointestinal (GI) tract, with the vast majority being diagnosed in the stomach, duodenum, or proximal small intestine. A few entities, especially diffuse large B-cell lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue, represent the majority of cases. In addition, there are diseases specific to or characteristic of the GI tract, and any type of systemic lymphoma can present in or disseminate to these organs. The recent advances in the genetic and molecular characterisation of lymphoid neoplasms have translated into notable changes in the classification of primary GI T-cell neoplasms and the recommended diagnostic approach to aggressive B-cell tumours. In many instances, diagnoses rely on morphology and immunophenotype, but there is an increasing need to incorporate molecular genetic markers. Moreover, it is also important to take into consideration the endoscopic and clinical presentations. This review gives an update on the most recent developments in the pathology and molecular pathology of upper GI lymphoproliferative diseases.

Impact of Genetics on Mature Lymphoid Leukemias and Lymphomas

Recurrent genetic aberrations have long been recognized in mature lymphoid leukemias and lymphomas. As conventional karyotypic and molecular cloning techniques evolved in the 1970s and 1980s, multiple cytogenetic aberrations were identified in lymphomas, often balanced translocations that juxtaposed oncogenes to the immunoglobulin (IG) or T-cell receptor (TR) loci, leading to dysregulation. However, genetic characterization and classification of lymphoma by conventional cytogenetic methods is limited by the infrequent occurrence of recurrent karyotypic abnormalities in many lymphoma subtypes and by the frequent difficulty in growing clinical lymphoma specimens in culture to obtain informative karyotypes. As higher-resolution genomic techniques developed, such as array comparative genomic hybridization and fluorescence in situ hybridization, many recurrent copy number changes were identified in lymphomas, and copy number assessment of interphase cells became part of routine clinical practice for a subset of diseases. Platforms to globally examine mRNA expression led to major insights into the biology of several lymphomas, although these techniques have not gained widespread application in routine clinical settings. With the advent of next-generation sequencing (NGS) techniques in the early 2000s, numerous insights into the genetic landscape of lymphomas were obtained. In contrast to the myeloid malignancies, most common lymphomas exhibit an at least somewhat mutationally complex genome, with few single driver mutations in the majority of patients. However, many recurrently mutated pathways have been identified across lymphoma subtypes, informing targeted therapeutic approaches that are beginning to make meaningful changes in the treatment of lymphoma. In addition to the ability to identify possible therapeutic targets, NGS techniques are highly amenable to the tracking of residual lymphoma following therapy, because of the presence of unique genetic "fingerprints" in lymphoma cells due to V(D)-J recombination at the antigen receptor loci. This review will provide an overview of the impact of novel genetic technologies on lymphoma classification, biology, and therapy.

The oncogene BCL6 is up-regulated in glioblastoma in response to DNA damage, and drives survival after therapy

The prognosis for people with the high-grade brain tumor glioblastoma is very poor, due largely to low cell death in response to genotoxic therapy. The transcription factor BCL6, a protein that normally suppresses the DNA damage response during immune cell maturation, and a known driver of B-cell lymphoma, was shown to mediate the survival of glioblastoma cells. Expression was observed in glioblastoma tumor specimens and cell lines. When BCL6 expression or activity was reduced in these lines, increased apoptosis and a profound loss of proliferation was observed, consistent with gene expression signatures suggestive of anti-apoptotic and pro-survival signaling role for BCL6 in glioblastoma. Further, treatment with the standard therapies for glioblastoma—ionizing radiation and temozolomide—both induced BCL6 expression in vitro, and an in vivo orthotopic animal model of glioblastoma. Importantly, inhibition of BCL6 in combination with genotoxic therapies enhanced the therapeutic effect. Together these data demonstrate that BCL6 is an active transcription factor in glioblastoma, that it drives survival of cells, and that it increased with DNA damage, which increased the survival rate of therapy-treated cells. This makes BCL6 an excellent therapeutic target in glioblastoma—by increasing sensitivity to standard DNA damaging therapy, BCL6 inhibitors have real potential to improve the outcome for people with this disease.

C-MYC, BCL2 and BCL6 Translocation in B-cell Non-Hodgkin Lymphoma Cases

C-MYC, BCL2 and BCL6 genes are the most commonly oncogenes involved in B-Cell lymphomas. Translocations of these oncogenes are associated with an aggressive clinical course. This study aims to elucidate the patterns of BCL6, BCL2 and C-MYC gene aberrations among Malaysian B-cell Non-Hodgkin Lymphoma (NHL) using fluorescence in situ hybridization (FISH). Eighty-one B-cell NHL tissue blocks were retrieved between the year 2011 to 2015 and investigated using immunohistochemistry and interphase FISH dual colour break-apart probes of BCL2, BCL6, C-MYC and IgH. A significant difference was detected between the nodal and extranodal sites in all the BCL2 (p=0.01), C-MYC (p=0.03) and IgH (p=0.006) cases except for BCL6 (p=0.2). Our study showed that BCL6 had the highest gene translocation while BCL2/BCL6 had the most mixed aberrations of gain copies and translocation, however no mixed aberrations of gain copies and translocation was found in C-MYC. None of the mixed gain copies and translocation was found in any of the germinal centre B-cell (GCB) subtype of Diffuse Large B-cell Lymphoma, however, five were found in BCL6 and IgH gene in the non-GCB subtype; while mixed gain copies and translocation cases of BCL2 gene was found in the Follicular Lymphoma cases only. The study found interesting findings of BCL2, C-MYC and IgH gene aberrations between nodal and extranodal sites. This information might benefit future study in predicting prognosis and determine effective therapeutic strategies in the multi-ethnic populations of Malaysia as well as the Asian population.

ZEB Proteins in Leukemia: Friends, Foes, or Friendly Foes?

ZEB1 and ZEB2 play pivotal roles in solid cancer metastasis by allowing cancer cells to invade and disseminate through the transcriptional regulation of epithelial-to-mesenchymal transition. ZEB expression is also associated with the acquisition of cancer stem cell properties and therapy resistance. Consequently, expression levels of ZEB1/2 and of their direct target genes are widely seen as reliable prognostic markers for solid tumor aggressiveness and cancer patient outcome.

Recent loss-of-function mouse models demonstrated that both ZEBs are also essential hematopoietic transcription factors governing blood lineage commitment and fidelity. Interestingly, both gain- and loss-of-function mutations have been reported in multiple hematological malignancies. Combined with emerging functional studies, these data suggest that ZEB1 and ZEB2 can act as tumor suppressors and/or oncogenes in blood borne malignancies, depending on the cellular context. Here, we review these novel insights and discuss how balanced expression of ZEB proteins may be essential to safeguard the functionality of the immune system and prevent leukemia.

Molecular Subtypes, Apoptosis and Proliferation Status in Indonesian Diffuse Large B-Cell Lymphoma Cases

Objective:

The diffuse large B-cell lymphoma (DLBCL) has two major molecular subtypes, germinal center B-cell-like (GCB) and non-GCB. These have differing behavior which affects overall patient survival. However, immunohistochemistry based molecular subtyping of Indonesian DLBCLs has been limited. This was the focus of the present study, with a focus of attention on the apoptotic index (AI) and the proliferation index (PI) of the two molecular subtypes.

Materials and Methods:

During the study period of 3.5 years, a total of 98 cases of DLBCL were identified. Molecular subtypes and PI were determined by immunohistochemistry and TUNEL method was used to determine the AI.

Result:

GCB accounted for 31 cases (31.6%) and non-GCB the remainder (68.4%). Gender showed a slight male predominance (54 cases, 55.1%), with a higher incidence in the extra-nodal region (57 cases, 58.2%). The AI and PI were significantly higher in GCB (p<0.001 in the Mann-Whitney test) and a Spearman correlation coefficient test showed that PI was positively correlated with AI (r=0.673, p<0.001).

Conclusion:

The findings indicate that the non-GCB subtype is more common than GCB in Indonesian DLBCL. GCB features significantly higher PI and AI, which themselves appear linked.

Inhibition of demethylase KDM6B sensitizes diffuse large B-cell lymphoma to chemotherapeutic drugs

Histone methylation and demethylation regulate B-cell development, and their deregulation correlates with tumor chemoresistance in diffuse large B-cell lymphoma, limiting cure rates. Since histone methylation status correlates with disease aggressiveness and relapse, we investigated the therapeutic potential of inhibiting histone 3 Lys27 demethylase KDM6B, in vitro, using the small molecule inhibitor GSK-J4. KDM6B is overexpressed in the germinal center B-cell subtype of diffuse large B-cell lymphoma, and higher KDM6B levels are associated with worse survival in patients with diffuse large B-cell lymphoma treated with R-CHOP. GSK-J4-induced apoptosis was observed in five (SU-DHL-6, OCI-Ly1, Toledo, OCI-Ly8, SU-DHL-8) out of nine germinal center B-cell diffuse large B-cell lymphoma cell lines. Treatment with GSK-J4 predominantly resulted in downregulation of B-cell receptor signaling and BCL6. Cell lines expressing high BCL6 levels or CREBBP/EP300 mutations were sensitive to GSK-J4. Our results suggest that B-cell receptor-dependent downregulation of BCL6 is responsible for GSK-J4-induced cytotoxicity. Furthermore, GSK-J4-mediated inhibition of KDM6B sensitizes germinal center B-cell diffuse large B-cell lymphoma cells to chemotherapy agents that are currently utilized in treatment regimens for diffuse large B-cell lymphoma.

Human Ribosomal RNA-Derived Resident MicroRNAs as the Transmitter of Information upon the Cytoplasmic Cancer Stress

Dysfunction of ribosome biogenesis induces divergent ribosome-related diseases including ribosomopathy and occasionally results in carcinogenesis. Although many defects in ribosome-related genes have been investigated, little is known about contribution of ribosomal RNA (rRNA) in ribosome-related disorders. Meanwhile, microRNA (miRNA), an important regulator of gene expression, is derived from both coding and noncoding region of the genome and is implicated in various diseases. Therefore, we performed in silico analyses using M-fold, TargetScan, GeneCoDia3, and so forth to investigate RNA relationships between rRNA and miRNA against cellular stresses. We have previously shown that miRNA synergism is significantly correlated with disease and the miRNA package is implicated in memory for diseases; therefore, quantum Dynamic Nexus Score (DNS) was also calculated using MESer program. As a result, seventeen RNA sequences identical with known miRNAs were detected in the human rRNA and termed as rRNA-hosted miRNA analogs (rmiRNAs). Eleven of them were predicted to form stem-loop structures as pre-miRNAs, and especially one stem-loop was completely identical with hsa-pre-miR-3678 located in the non-rDNA region. Thus, these rmiRNAs showed significantly high DNS values, participation in regulation of cancer-related pathways, and interaction with nucleolar RNAs, suggesting that rmiRNAs may be stress-responsible resident miRNAs which transmit stress-tuning information in multiple levels.

[Prognostic analysis of BCL-2/MYC double- hit in diffuse large B-cell lymphoma]

OBJECTIVE

To investigate the effect of BCL-2/MYC double-hit on prognosis in diffuse large B-cell lymphoma（DLBCL）.

METHODS

A retrospective study was conducted to investigate clinical and pathological data of 111 patients with DLBCL. CD10, BCL-6, MUM-1, BCL-2 protein expressions were examined by immune-histochemical methods, and abnormal BCL-2 and MYC genes were analyzed by FISH for patients with sufficient pathological data. SAS 8.2 was adopted to perform Chi- square test, COX's proportional Hazard Model, Life table survival analyses.

RESULTS

Of 111 patients, male 77 cases, female 34 cases, the median age was 55（14-85）years, CD10, BCL-6, MUM-1, BCL-2 positive rates were 15.7%（16/102）, 58.8%（60/102）, 33.0%（34/103）, 74.8（77/103）respectively, the abnormal rate of BCL-2 gene was 43.1%（25/58, 24 cases with multiple copies, 1 case with translocation）, and the abnormal rate of MYC gene was 20.4%（10/49, 10 cases with multiple copies）. Coexistence of BCL-2 and MYC genes abnormalities accounted for 13.0%（6/46）. According to the classification of Hans model, GCB subgroup accounted for 41.2%（42/102）, and non-GCB subgroup 58.8%（60/102）, the median survival time was 24 months, 3-year and 5-year overall survival rates were 48.5% and 39.7% respectively. Overall survival rates of normal and abnormal BCL-2 gene were 34.2%，22.8%, respectively with no statistical significance（P=0.770）. Overall survival rates of normal and abnormal MYC gene were 35.9% and 22.2% ，with no statistical significance（P=0.650）. Overall survival rate of double-hit was 0, far worse than that of single abnormal gene（P=0.034）, which implied double-hit of BCL-2 and MYC gene abnormality to be adverse prognostic factors. BCL-6 protein express could be classified as benign prognostic factors, while ECOG score≥2, escalated IPI index as adverse prognostic factors, and further COX risk model regression analysis indicated that ECOG score, IPI grading and treatment methods were independently adverse factors affecting prognosis. Comprehensive therapy based on chemotherapy could improve outcome.

CONCLUSION

BCL-2/MYC genes double-hit was the factor for the adverse outcome in DLBCL patients. However, ECOG score, IPI risk grading and treatment methods were the independent factors affecting prognosis.

P38 MAPK expression and activation predicts failure of response to CHOP in patients with Diffuse Large B-Cell Lymphoma

BACKGROUND

The p38 MAPK is constitutively activated in B-NHL cell lines and regulates chemoresistance. Accordingly, we hypothesized that activated p38 MAPK may be associated with the in vivo unresponsiveness to chemotherapy in B-NHL patients.

METHODS

Tissue microarrays generated from eighty untreated patients with Diffused Large B Cell Lymphoma (DLBCL) were examined by immunohistochemistry for the expression of p38 and phospho p38 (p-p38) MAPK. In addition, both Bcl-2 and NF-κB expressions were determined. Kaplan Meier analysis was assessed.

RESULTS

Tumor tissues expressed p38 MAPK (82 %) and p-p38 MAPK (30 %). Both p38 and p-p38 MAPK expressions correlated with the high score performance status. A significant correlation was found between the expression p-p38 and poor response to CHOP. The five year median follow-up FFS was 81 % for p38(-) and 34 % for p38(+) and for OS was 83 % for p38(-) and 47 % for p38(+). The p-p38(+) tissues expressed Bcl-2 and 90 % of p-p38(-) where Bcl-2(-). The coexpression of p-p38 and Bcl-2 correlated with pool EFS and OS. There was no correlation between the expression of p-p38 and the expression of NF-κB.

CONCLUSION

The findings revealed, for the first time, that a subset of patients with DLBCL and whose tumors expressed high p-p38 MAPK responded poorly to CHOP therapy and had poor EFS and OS. The expression of p38, p-p38, Bcl2 and the ABC subtype are significant risk factors both p38 and p-p38 expressions remain independent prognostic factors.

Genetic lesions in diffuse large B-cell lymphomas

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma in adults, accounting for 35%-40% of all cases. The combination of the anti-CD20 monoclonal antibody rituximab with anthracycline-based combination chemotherapy (R-CHOP, rituximab with cyclophosphamide, doxorubicin, vincristine and prednisone) lead to complete remission in most and can cure more than half of patients with DLBCL. The diversity in clinical presentation, as well as the pathologic and biologic heterogeneity, suggests that DLBCL comprises several disease entities that might ultimately benefit from different therapeutic approaches. In this review, we summarize the current literature focusing on the genetic lesions identified in DLBCL.

MYC expression in concert with BCL2 and BCL6 expression predicts outcome in Chinese patients with diffuse large B-cell lymphoma, not otherwise specified

Recent studies provide convincing evidence that a combined immunohistochemical or fluorescence in situ hybridization (FISH) score of MYC, BCL2, BCL6 proteins and MYC translocations predicted outcome in diffuse large B-cell lymphoma (DLBCL) patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). However, by far, all these researches are based on Western populations. Therefore, we investigate the prognostic relevance of MYC-, BCL2- and BCL6-rearrangements and protein expression by immunohistochemistry and FISH from 336 de novo DLBCL, NOS treated with CHOP or R-CHOP. Breaks in MYC and BCL6, and fusion in IGH/BCL2 were detected in 9.7%, 20.0%, and 11.1% of the cases, respectively, and were not significantly associated with clinical outcomes. Protein overexpression of MYC (≥40%), BCL2 (≥70%) and BCL6 (≥50%) was encountered in 51%, 51% and 36% of the tumors, respectively. On the basis of MYC, BCL2 and BCL6 expression, double-hit scores (DHSs) and triple-hit score (THS) were assigned to all patients with DLBCL. Patients with high MYC/BCL2 DHS, high MYC/BCL6 DHS and high THS had multiple adverse prognostic factors including high LDH level, poor performance status, advanced clinical stage, high International Prognostic Index (IPI) score, and non-germinal center B-cell. In univariate analysis, high MYC/BCL2 DHS, high MYC/BCL6 DHS and high THS were associated with inferior OS and PFS in both CHOP and R-CHOP cohorts (P<0.05). The highly significant correlations with OS and PFS were maintained in multivariate models that controlled for IPI (P<0.05). DLBCLs with high DHSs and high THS share the clinical features and poor prognosis of double-hit lymphoma (P>0.05). These data together suggest that the immunohistochemical DHSs and THS defined a large subset of DLBCLs with double-hit biology and was strongly associated with poor outcome in patients treated with R-CHOP or CHOP.

Inhibition of ZEB1 by miR-200 characterizes Helicobacter pylori-positive gastric diffuse large B-cell lymphoma with a less aggressive behavior

Primary gastric diffuse large B-cell lymphomas may or may not have a concurrent component of mucosa-associated lymphoid tissue lymphoma. Diffuse large B-cell lymphoma/mucosa-associated lymphoid tissue lymphomas are often associated with Helicobacter pylori (H. pylori) infection, suggesting that the large cells are transformed from mucosa-associated lymphoid tissue lymphomas. In contrast, only limited data are available on the clinical and molecular features of pure gastric diffuse large B-cell lymphomas. In 102 pure gastric diffuse large B-cell lymphomas, we found H. pylori infection in 53% of the cases. H. pylori-positive gastric diffuse large B-cell lymphomas were more likely to present at an earlier stage (73% vs 52% at stage I/II, P=0.03), to achieve complete remission (75% vs 43%, P=0.001), and had a better 5-year disease-free survival rate (73% vs 29%, P<0.001) than H. pylori-negative gastric diffuse large B-cell lymphomas. Through genome-wide expression profiles of both miRNAs and mRNAs in nine H. pylori-positive and nine H. pylori-negative gastric diffuse large B-cell lymphomas, we identified inhibition of ZEB1 (zinc-finger E-box-binding homeobox 1) by miR-200 in H. pylori-positive gastric diffuse large B-cell lymphomas. ZEB1, a transcription factor for marginal zone B cells, can suppress BCL6, the master transcription factor for germinal center B cells. In 30 H. pylori-positive and 30 H. pylori-negative gastric diffuse large B-cell lymphomas, we confirmed that H. pylori-positive gastric diffuse large B-cell lymphomas had higher levels of miR-200 by qRT-PCR, and lower levels of ZEB1 and higher levels of BCL6 using immunohistochemistry. As BCL6 is a known predictor of a better prognosis in gastric diffuse large B-cell lymphomas, our data demonstrate that inhibition of ZEB1 by miR-200, with secondary increase in BCL6, is a molecular event that characterizes H. pylori-positive gastric diffuse large B-cell lymphomas with a less aggressive behavior.

Role of Helicobacter pylori in gastric mucosa-associated lymphoid tissue lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent extranodal marginal zone B-cell lymphoma, originating in acquired MALT that is induced in mucosal barriers as part of a normal adaptive immune response to a chronic immunoinflammatory stimulus, most notably chronic infection by Helicobacter pylori (H. pylori). This antigenic stimulation initially leads to lymphoid hyperplasia; the acquisition of additional genetic aberrations culminates in the activation of intracellular survival pathways, with disease progression due to proliferation and resistance to apoptosis, and the emergence of a malignant clone. There are descriptions of MALT lymphomas affecting practically every organ and system, with a marked geographic variability partially attributable to the epidemiology of the underlying risk factors; nevertheless, the digestive system (and predominantly the stomach) is the most frequently involved location, reflecting the gastrointestinal tract’s unique characteristics of contact with foreign antigens, high mucosal permeability, large extension and intrinsic lymphoid system. While early-stage gastric MALT lymphoma can frequently regress after the therapeutic reversal of the chronic immune stimulus through antibiotic eradication of H. pylori infection, the presence of immortalizing genetic abnormalities, of advanced disease or of eradication-refractoriness requires a more aggressive approach which is, presently, not consensual. The fact that MALT lymphomas are rare neoplasms, with a worldwide incidence of 1-1.5 cases per 10⁵ population, per year, limits the ease of accrual of representative series of patients for robust clinical trials that could sustain informed evidence-based therapeutic decisions to optimize the quality of patient care.

Prognostic value of immunohistochemical algorithms in gastrointestinal diffuse large B-cell lymphoma

Background

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous clinicopathological entity, and its molecular classification into germinal center B cell-like (GCB) and activated B cell-like (ABC) subtypes using gene expression profile analysis has been shown to have prognostic significance. Recent attempts have been made to find an association between immunohistochemical findings and molecular subgroup, although the clinical utility of immunohistochemical classification remains uncertain.

Methods

The clinicopathological features and follow-up data of 68 cases of surgically resected gastrointestinal DLBCL were analyzed. Using the immunohistochemical findings on tissue microarray, the cases were categorized into GCB and non-GCB subtypes according to the algorithms proposed by Hans, Muris, Choi, and Tally.

Results

The median patient age was 56 years (range, 26-77 years). Of the 68 cases included, 39.7% (27/68) involved the stomach, and 60.3% (41/68) involved the intestines. The GCB and non-GCB groups sorted according to Hans, Choi, and Tally algorithms, but not the Muris algorithm, were closely concordant (Hans vs. Choi, κ=0.775, P<0.001; Hans vs. Tally, κ=0.724, P<0.001; Choi vs. Tally, κ=0.528, P<0.001). However, there was no prognostic difference between the GCB and non-GCB subtypes, regardless of the algorithm used. On univariate survival analyses, international prognostic index risk group and depth of tumor invasion both had prognostic significance.

Conclusion

The Hans, Choi, and Tally algorithms might represent identical DLBCL subgroups, but this grouping did not correlate with prognosis. Further studies may delineate the association between immunohistochemical subgroups and prognosis.

Differences in the cytogenetic alteration profiles of diffuse large B-cell lymphoma among Chinese and American patients

To study the similarities and differences of cytogenetic alterations in diffuse large B-cell lymphoma (DLBCL) between Asian and Caucasian patients, we compared the cytogenetic profiles of Chinese and American DLBCL cases by analyzing conventional karyotypes and select fluorescence in situ hybridization (FISH) findings. We used interphase FISH analyses to determine the incidence of the t(14;18) and BCL6 and MYC rearrangements. Immunohistochemical analysis was used to categorize the lymphomas into the germinal center B-cell-like (GCB) or non-GCB-DLBCL subtypes, according to the Hans algorithm. Our data suggested that Chinese patients had cytogenetic profiles for GCB-DLBCL that differed from those of their American counterparts; specifically, the Chinese GCB patients exhibited greater frequencies of BCL6 rearrangements and gains of 1q and 11q but lower incidence of the t(14;18). Non-GCB-DLBCL in both the Chinese and American patients was characterized by recurrent gains of 3/3q and 18/18q. The incidences of both BCL6 rearrangement and t(14;18) were similar in Chinese and American non-GCB-DLBCL cases.

DNA-binding factor CTCF and long-range gene interactions in V(D)J recombination and oncogene activation

Regulation of V(D)J recombination events at immunoglobulin (Ig) and T-cell receptor loci in lymphoid cells is complex and achieved via changes in substrate accessibility. Various studies over the last year have identified the DNA-binding zinc-finger protein CCCTC-binding factor (CTCF) as a crucial regulator of long-range chromatin interactions. CTCF often controls specific interactions by preventing inappropriate communication between neighboring regulatory elements or independent chromatin domains. Although recent gene targeting experiments demonstrated that the presence of the CTCF protein is not required for the process of V(D)J recombination per se, CTCF turned out to be essential to control order, lineage specificity and to balance the Ig V gene repertoire. Moreover, CTCF was shown to restrict activity of κ enhancer elements to the Ig κ locus. In this review, we discuss CTCF function in the regulation of V(D)J recombination on the basis of established knowledge on CTCF-mediated chromatin loop domains in various other loci, including the imprinted H19-Igf2 locus as well as the complex β-globin, MHC class II and IFN-γ loci. Moreover, we discuss that loss of CTCF-mediated restriction of enhancer activity may well contribute to oncogenic activation, when in chromosomal translocations Ig enhancer elements and oncogenes appear in a novel genomic context.

Myc-mediated repression of microRNA-34a promotes high-grade transformation of B-cell lymphoma by dysregulation of FoxP1

Gastric marginal zone B-cell lymphoma of MALT type (MALT lymphoma) arises in the context of chronic inflammation induced by the bacterial pathogen Helicobacter pylori. Although generally considered an indolent disease, MALT lymphoma may transform to gastric diffuse large B-cell lymphoma (gDLBCL) through mechanisms that remain poorly understood. By comparing microRNA expression profiles of gastric MALT lymphoma and gDLBCL, we have identified a signature of 27 deregulated microRNAs(miRNAs) that share the characteristic of being transcriptionally repressed by Myc. Myc overexpression was consequently detected in 80% of gDLBCL but only 20% of MALT lymphomas spotted on a tissue microarray. A highly similar signature of Myc-repressed miRNAs was further detected in nodal DLBCL. Small interfering RNA-mediated knock-down of Myc blocked proliferation of DLBCL cell lines. Of the Myc-repressed miRNAs down-regulated in malignant lymphoma, miR-34a showed the strongest antiproliferative properties when overexpressed in DLBCL cells. We could further attribute miR-34a's tumor-suppressive effects to deregulation of its target FoxP1. FoxP1 overexpression was detected in gDLBCL but not in gastric MALT lymphoma; FoxP1 knock-down efficiently blocked DLBCL proliferation. In conclusion, our results elucidate a novel Myc- and FoxP1-dependent pathway of malignant transformation and suggest miR-34a replacement therapy as a promising strategy in lymphoma treatment.

Molecular Aspects of H. pylori-Related MALT Lymphoma

Helicobacter pylori-related extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue is a paradigm for malignancy arising in an inflammatory background. While the diagnosis of H. pylori gastritis is often straightforward, distinction between severe gastritis and early lymphoma can be difficult and requires careful assessment of clinical findings in addition to histological features and immunohistochemical results. A number of cytogenetic abnormalities have been discovered in H. pylori-related lymphomas and several have clinical importance, related to the responsiveness of lymphoma to H. pylori eradication therapy, but routine molecular studies are not widely utilized. While molecular methods may be used in equivocal cases, a trial of conservative therapy is warranted given the propensity for these lymphomas to regress with eradication of the organism. Once therapy is initiated, care must be taken to avoid a premature assignment of disease refractoriness because complete response can take several months to more than a year. Cases truly refractory to H. pylori eradication therapy may be treated with adjuvant chemoradiation with a high response rate.

BCL6 gene rearrangement and protein expression are associated with large cell presentation of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is an indolent B-cell lymphoma, which is often localized in the stomach. It is characterized by typical morphology, immunology, cytogenetics and expression profile. The coexistence of a large B-cell lymphoma and a MALT lymphoma in the gastrointestinal tract is defined as a composite lymphoma (ComL) and, as we have previously shown, is almost always the consequence of secondary transformation of MALT lymphoma. Here, we have analyzed a panel of seven MALT lymphomas, seven ComL and thirteen large cell variants of marginal zone B-cell lymphomas (MZBL) using FISH for the detection of rearrangements of IGH, MALT1, BCL6, BCL10 and FOXP1 and immunohistochemistry for Bcl6, Bcl10 and FoxP1. Translocations involving IGH were found in 10/27 lymphomas including two cases with IGH-BCL6 fusion and one with IGH-BCL10 fusion; in 7/10 cases, the translocation partner was not identified. Bcl10 and FoxP1 protein expression was heterogeneous throughout the series. Genetic rearrangements of BCL6 and Bcl6 protein expression were found almost exclusively in the large cell components of the ComL and the large cell extranodal MZBL (p = 0.2093 and p = 0.0261, respectively). These findings suggest Bcl6 as a marker for transformation of MALT lymphoma.

Primary gastric non-Hodgkin's lymphoma in Chinese patients: clinical characteristics and prognostic factors

Background

Optimal management and outcome of primary gastric lymphoma (PGL) have not been well defined in the rituximab era. This study aimed to analyze the clinical characteristics, prognostic factors, and roles of different treatment modalities in Chinese patients with PGL.

Methods

The clinicopathological features of 83 Chinese patients with PGL were retrospectively reviewed. Staging was performed according to the Lugano staging system for gastrointestinal non-Hodgkin's lymphoma.

Results

The predominant pathologic subtype among Chinese patients with PGL in our study was diffuse large B cell lymphoma (DLBCL), followed by mucosa-associated lymphoid tissue (MALT) lymphoma. Among the 57 patients with gastric DLBCL, 20 patients (35.1%) were classified as the germinal center B cell-like (GCB) subtype and 37 patients (64.9%) as the non-GCB subtype. The 83 patients had a five-year overall survival (OS) and event-free survival (EFS) of 52% and 59%, respectively. Cox regression analysis showed that stage-modified international prognostic index (IPI) and performance status (PS) were independent predictors of survival. In the 67 B-cell lymphoma patients who received chemotherapy, 36 patients treated with rituximab (at least 3 cycles) had a mean OS of 72 months (95% CI 62-81) versus 62 months (95% CI 47-76) for patients without rituximab treatment (P = 0.021).

Conclusion

The proportion of Chinese gastric DLBCL cases with non-GCB subtype was higher than the GCB subtype. Stage-modified IPI and PS were effective prognostic factors in Chinese patients with PGL. Our data suggested that primary gastric B-cell lymphoma might have an improved outcome with rituximab in addition to chemotherapy. More studies are necessary, preferentially large prospective randomized clinical trials to obtain more information on the impact of the rituximab in the primary gastric B-cell lymphoma.

B-cell receptor signaling and CD40 ligand-independent T cell help cooperate in Helicobacter-induced MALT lymphomagenesis

Gastric B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) develops in the context of chronic inflammation caused by Helicobacter pylori infection. Most pathophysiological features of the early stages of MALT lymphomagenesis can be reproduced by experimental infection of BALB/c mice with Helicobacter species. We have previously shown that MALT lymphomas are infiltrated by T-helper cell type 2-polarized T cells and that human and murine tumor B cells carry polyreactive surface immunoglobulins. Using the murine model of the disease, in this study we show that explanted tumor B cells proliferate upon stimulation with the same panel of self and foreign antigens that are recognized by their surface antibodies. Tumor cell proliferation is strongly enhanced by the presence of intratumoral CD4(+) T cells in a CD40/CD40L-independent manner. A large proportion of tumor-infiltrating CD4(+) T cells are CD25(+)FoxP3(+) regulatory T cells (Tregs) with highly suppressive activity, which are recruited by the tumor cells through secretion of the Treg-attracting chemokines CCL17 and CCL22. The depletion of CD25(+) cells was as efficient as CD4(+) T cell depletion in blocking tumor growth in vitro and in vivo. In conclusion, our data suggest that B-cell receptor-derived signals cooperate with T-helper cell signals in driving the progression of MALT lymphoma, providing an explanation for the unique antigen dependence of this B-cell malignancy.

CD44 activation in mature B-cell malignancies by a novel recurrent IGH translocation

Using inverse polymerase chain reaction, we identified CD44, located on chromosome 11p13, as a novel translocation partner of IGH in 9 of 114 cases of gastric, nongastric extranodal, follicular, and nodal diffuse large B-cell lymphoma (DLBCL). Notably, these translocations involving IGHSμ were detected in follicular lymphomas and exclusively in germinal center B cell-ike (GCB)–DLBCLs. CD44 is not expressed in reactive GC B cells. The IGHSμ/CD44 translocations substitute Sμ for the CD44 promoter and remove exon 1 of CD44, resulting in the overexpression of Iμ-CD44 hybrid mRNA transcripts activated from derivative 11 that encode a new CD44 variant lacking the leader peptide and with a unique C-terminus (CD44ΔEx1). When overexpressed in vitro in the CD44− GCB-DLBCL cell line BJAB, CD44ΔEx1–green fluorescent protein localized to the cytoplasm and nucleus, whereas CD44s–green fluorescent protein (standard form) localized to the plasma membrane. The ectopic expression of CD44ΔEx1 in BJAB cells enhanced their proliferation rate and clonogenic ability, indicating a possible pathogenic role of the translocation.

Diffuse large B-cell lymphoma in Chinese patients: immunophenotypic and cytogenetic analyses of 124 cases

In diffuse large B-cell lymphoma (DLBCL), BCL2 expression usually correlates with the t(14;18) (q32;q21) in germinal center B-cell (GCB) subtype and with gain/amplification of chromosome 18q21 in the activated B cell-like subtype. Studies have suggested that the GCB subtype is less common in Chinese than in Western populations. We studied 124 Chinese DLBCL cases using immunohistochemical, conventional cytogenetics, and interphase fluorescence in situ hybridization analyses. A cohort of 114 well-characterized DLBCL cases from Western populations was also analyzed for comparison. Lower incidences of the GCB subtype (P = .0001) and the t(14;18) translocation (P = .0001) were present in Chinese cases. However, BCL2 overexpression was more frequent in Chinese compared with Western cases (P = .0054). BCL2 expression was associated with gain of chromosome 18/18q in the Chinese and Western cohorts. More interestingly, BCL2 expression was associated with gain of chromosome 3/3q in Chinese DLBCL cases, whereas this association was less significant in Western cases.

[Extranodal diffuse large B-cell lymphoma--an organotypic disease?]

Roughly 30-40% of diffuse large B-cell lymphomas (DLBCL) arise primarily in extranodal sites. Most frequently, they occur in the gastrointestinal tract, especially in the gastric mucosa. They also occur in the central nervous system, as testicular lymphomas, in the lungs, or in the skin. Morphologically, they show the whole spectrum of peripheral B-blasts: centroblasts, immunoblasts, or plasmoblasts. Thus, there is no actual difference in their cytomorphological presentation compared to their nodal-and frequently systemic-counterparts. However, recent data point to profound differences in primary extranodal DLBCL compared to primary nodal tumors, as well as to each other, frequently relating to their molecular characteristics and especially implying organotypic features. These characteristics may relate to a particular organotypic site of origin, or the particular clinico-pathogenetic setting in which the tumors arise. This is exemplified in the description of the DLBCL subtypes as defined by the World Health Organization classification (mediastinal or intravascular B-cell lymphoma; primary effusion lymphoma). On the other hand, primary extranodal DLBCL are frequently characterized by a particular (cyto-)genetic constitution, often related to their site of origin. Finally, some preliminary data on gene expression profiling strongly argue in favor of particular gene signatures for primary extranodal DLBCL, and hence in favor of particular organotypic transformation pathways.

The GCB subtype of diffuse large B-cell lymphoma is less frequent in Asian countries

Patients with the germinal center B-cell-like (GCB) subtype of diffuse large B-cell lymphoma (DLBCL) have a significantly better survival rate than those with non-GCB DLBCL. Several studies have examined the proportions of GCB and non-GCB subtypes in large series of DLBCL patients, but it remains unclear if these proportions are the same in different countries. We performed an immunohistochemical analysis of the numbers of GCB and non-GCB subtypes in a large number of patients with DLBCL in Japan and compared the results with literature data for other countries. We found that 71 of 248 patients (29%) had the GCB phenotype and 177 patients (71%) had the non-GCB subtype of DLBCL among our patient population. Assessment of data collected from other studies showed that 31% of DLBCL patients (102/330) have the GCB subtype in Asian countries, but 50% (206/416) express GCB phenotypes in Western countries; based on these data, the occurrence of the GCB subtype of DLBCL was significantly less in Asian countries (p<0.001). Since patients with the GCB phenotype of DLBCL have better survival, future studies of DLBCL should recognize the difference in the proportions of GCB and non-GCB subtypes of DLBCL between Asian and Western populations.

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.

Primary gastric lymphoma pathogenesis and treatment: what has changed over the past 10 years?

Primary gastric (PG) lymphomas are generally non-Hodgkin lymphomas (NHL). They represent 5% of gastric malignancies and show an apparently increasing incidence worldwide. The most common histological subtypes are diffuse large B-cell and marginal zone B-cell NHL of the mucosa-associated lymphoid tissue (MALT)-type. Pathogenesis is often related to Helicobacter pylori infection (HPI). There is still no consensus on the optimal treatment for PG lymphoma. Nowadays surgery is limited to rare cases and radiotherapy--combined or not with chemotherapy--represents an effective therapeutic option ensuring long-term, organ-salvage benefits mainly in aggressive histological subtypes. Additionally, the description of MALT lymphomas has made the situation even more complex, because antibiotics alone can induce lasting remissions in those cases associated with HPI. Consequently, a global therapeutic approach to the cure of PG-NHL has completely changed over the last 10 years: innovative, conservative options to reduce treatment toxicity, thus preventing systemic relapses, have made their appearance and are on the rise.