Concurrent expression of MYC and BCL2 in diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone

C-MYC aberrations as prognostic factors in diffuse large B-cell lymphoma: a meta-analysis of epidemiological studies

Objectives

Various studies have investigated the prognostic value of C-MYC aberrations in diffuse large B-cell lymphoma (DLBCL). However, the role of C-MYC as an independent prognostic factor in clinical practice remains controversial. A systematic review and meta-analysis were performed to clarify the clinical significance of C-MYC aberrations in DLBCL patients.

Methods

The pooled hazard ratios (HRs) for overall survival (OS) and event-free survival (EFS) were calculated as the main effect size estimates. The procedure was conducted according to the Cochrane handbook and PRISMA guidelines, including the use of a heterogeneity test, publication bias assessment, and meta-regression, as well as subgroup analyses.

Results

Twenty-four eligible studies enrolling 4662 patients were included in this meta-analysis. According to the nature of C-MYC aberrations (gene, protein, and mRNA), studies were divided into several subgroups. For DLBCL patients with C-MYC gene abnormalities, the combined HR was 2.22 (95% confidence interval, 1.89 to 2.61) for OS and 2.29 (95% confidence interval, 1.81 to 2.90) for EFS, compared to patients without C-MYC gene abnormalities. For DLBCL patients with overexpression of C-MYC protein and C-MYC mRNA, pooled HRs for OS were 2.13 and 1.62, respectively. C-MYC aberrations appeared to play an independent role among other well-known prognostic factors in DLBCL. Addition of rituximab could not overcome the inferior prognosis conferred by C-MYC.

Conclusion

The present systematic review and meta-analysis confirm the prognostic value of C-MYC aberrations. Screening of C-MYC should have definite prognostic meaning for DLBCL stratification, thus guaranteeing a more tailored therapy.

MYC protein expression is associated with poor prognosis in diffuse large B cell lymphoma patients treated with RCHOP chemotherapy

This study aims to investigate the prognostic significance of the MYC protein expression in diffuse large B cell lymphoma (DLBCL) patients treated with RCHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone). A total of 60 patients with DLBCL from 2008 to 2013 were included. Formalin-fixed, paraffin-embedded DLBCL samples were analyzed for MYC protein expression and divided into high or low MYC group. The MYC protein expression and the international prognostic variables were evaluated. The high MYC protein expression predicted a shorter 3-year estimated overall survival (OS) and progression-free survival (PFS) versus the low MYC protein expression (57 % vs. 96 %, P < 0.001 and 50 % vs. 96 %, P = 0.001, respectively). Multivariate analysis confirmed the prognostic significance of the MYC protein expression for both OS (HR, 11.862; 95 % CI, 1.462-96.218; P = 0.021) and PFS (HR, 6.073; 95 % CI, 1.082-34.085; P = 0.040). MYC protein expression with International Prognostic Index (IPI) score distinguished patients into three risk groups with different 3-year OS rates (χ (2) 23.079; P < 0.001) and distinct 3-year PFS rates (χ (2) 15.862; P < 0.001). This study suggests that the MYC protein expression is an important inferior prognostic factor for survival in patients with DLBCL treated with RCHOP. The combinative model with IPI score and MYC protein expression could stratify DLBCL patients into prognostically relevant subgroups more effectively than either the IPI or the MYC alone.

Clinicopathologic characterization of diffuse-large-B-cell lymphoma with an associated serum monoclonal IgM component

Recently, diffuse-large-B-cell lymphoma (DLBCL) associated with serum IgM monoclonal component (MC) has been shown to be a very poor prognostic subset although, detailed pathological and molecular data are still lacking. In the present study, the clinicopathological features and survival of IgM-secreting DLBCL were analyzed and compared to non-secreting cases in a series of 151 conventional DLBCL treated with R-CHOP. IgM MC was detected in 19 (12.5%) out of 151 patients at disease onset. In 17 of these cases secretion was likely due to the neoplastic clone, as suggested by the expression of heavy chain IgM protein in the cytoplasm of tumor cells. In IgM-secreting cases immunoblastic features (p<.0001), non-GCB-type (p = .002) stage III-IV(p = .003), ≥ 2 extra nodal sites (p<.0001), bone-marrow (p = .002), central-nervous-system (CNS) involvement at disease onset or relapse (p<.0001), IPI-score 3-5 (p = .009) and failure to achieve complete remission (p = .005), were significantly more frequent. FISH analyses for BCL2, BCL6 and MYC gene rearrangements detected only two cases harboring BCL2 gene translocation and in one case a concomitant BCL6 gene translocation was also observed. None of the IgM-secreting DLBCL was found to have L265P mutation of MYD88 gene. Thirty-six month event-free (11.8% vs 66.4% p<.0001), progression-free (23.5% vs 75.7%, p<.0001) and overall (47.1% vs 74.8%, p<.0001) survivals were significantly worse in the IgM-secreting group. In multivariate analysis IgM-secreting (p = .005, expB = 0.339, CI = 0.160-0.716) and IPI-score 3-5 (p = .010, expB = 0.274, CI = 0.102-0.737) were the only significant factors for progression-free-survival. Notably, four relapsed patients, who were treated with salvage immunochemotherapy combined with bortezomib or lenalidomide, achieved lasting remission. Our data suggests that IgM-secreting cases are a distinct subset of DLBCL, originating from activated-B-cells with terminally differentiated features, prevalent extra nodal dissemination and at high risk of CNS involvement.

Appropriate management of molecular subtypes of diffuse large B-cell lymphoma

In recent years, we have made huge strides in our understanding of the molecular complexity of diffuse large B-cell lymphoma (DLBCL). New technologies, such as gene expression profiling, RNA interference screening, and DNA sequencing, have identified several new signaling pathways and therapeutic targets for drug development. While we once considered DLBCL to be a single disease entity, recent insights have helped identify the existence of at least three distinct molecular diseases: a germinal center B-cell-like subtype, an activated B-cell-like subtype, and a primary mediastinal B-cell lymphoma subtype. All three subtypes originate from different stages of B-cell differentiation and are characterized by distinct mechanisms of oncogenic activation. This classification of DLBCL has laid the foundation for the development of new agents and novel strategies that target individual subtypes.

p53 expression is a strong marker of inferior survival in de novo diffuse large B-cell lymphoma and may have enhanced negative effect with MYC coexpression: a single institutional clinicopathologic study

OBJECTIVES

To examine interactions among clinical factors and pathologic biomarkers in predicting the outcome of patients with diffuse large B-cell lymphoma (DLBCL) treated with rituximab-based immunochemotherapy.

METHODS

In 85 patients treated at a single institution, clinicopathologic variables were analyzed, including the International Prognostic Index (IPI); germinal/nongerminal center phenotype; MYC, p53, BCL2, Ki-67, and Epstein-Barr virus (EBV) expression; and MYC translocation status.

RESULTS

In univariate analysis, overall survival (OS) was worse for patients with high IPI scores, nongerminal center phenotype, high MYC and p53 expression by immunohistochemistry, and EBV positivity. In multivariable analysis, p53 expression was the strongest prognostic factor (P < .05) independent of IPI and cell of origin. A significant positive association between p53 and MYC expression was found. Moreover, coexpression of p53/MYC had an enhanced negative effect on OS independent of BCL2 expression.

CONCLUSIONS

Immunohistochemical assessment of p53, particularly in combination with MYC, could be useful in identifying a high-risk subgroup of DLBCL.

Moving beyond rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone for diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common B-cell non-Hodgkin lymphoma (NHL). While the de facto treatment standard R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) is curative in most cases, it is ineffective for a significant proportion of patients, particularly those with intermediate and high-risk disease. Efforts to improve upon the results of R-CHOP have principally explored dose intensification of chemotherapy and resulted in considerable additive toxicity without clear benefit. DLBCL is not a uniform disease, however, and can be dissected into distinct molecular subtypes by gene expression profiling. These subtypes are characterized by distinct oncogenic mechanisms of activation and addictions to aberrant intracellular signaling pathways. Novel therapeutic agents that target these pathway addictions are emerging, and may have specific activity within molecular subtypes of DLBCL. To move beyond R-CHOP for all patients with DLBCL, targeted therapies added to the most effective chemotherapy platforms must be studied within the context of molecularly defined subsets.

Pathology consultation on intermediate-to-large B-cell lymphomas

OBJECTIVES

Intermediate-to-large B-cell lymphomas represent a heterogeneous group of aggressive lesions frequently encountered in practice. The differential diagnosis includes the most common of all lymphomas, diffuse large B-cell lymphoma (DLBCL), as well as Burkitt lymphoma (BL), B-lymphoblastic lymphoma, and the blastoid variant of mantle cell lymphoma. In recent decades, gene expression profiling studies have clarified the biologic origins and features of these diseases. Moreover, clinically relevant subtypes of DLBCL have been identified, and a new category was defined: B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL. Herein, we review the salient diagnostic features of the various entities within this differential diagnosis and provide a stepwise diagnostic approach for dealing with challenging cases.

METHODS

A case-based approach is used to highlight diagnostic dilemmas and clinical decision points within the differential diagnosis of intermediate-to-large B-cell lymphomas.

RESULTS

Based on the published literature and World Health Organization criteria, we suggest a diagnostic algorithm for appropriate classification of these lymphomas.

CONCLUSIONS

Correct classification of intermediate-to-large B-cell lymphomas is important, because prognosis and therapeutic approach vary for different tumors and tumor subclasses. Understanding both disease-specific criteria and pathologic features that influence clinical behavior within a category is imperative for evaluation of these lymphomas.

Complete response to induction therapy in patients with Myc-positive and double-hit non-Hodgkin lymphoma is associated with prolonged progression-free survival

BACKGROUND

Myc-positive B-cell non-Hodgkin lymphoma (NHL) with or without a B-cell chronic lymphocytic leukemia/lymphoma 2 (BCL2) rearrangement is associated with inferior progression-free survival (PFS) and overall survival (OS). In this study, the authors reviewed the outcomes of patients with myc-positive and double-hit NHL at The Ohio State University.

METHODS

All patients who had non-Burkitt, aggressive B-cell NHL from 2008 to 2011 were assessed for the t(14;18) translocation and for v-myc avian myelocytomatosis viral oncogene homolog (CMYC) rearrangements at diagnosis, and all myc-positive patients were included in the current analysis. Associations with clinical characteristics were described, and univariable and multivariable models were used to assess correlations between clinical variables and outcomes.

RESULTS

Of 49 myc-positive patients, 29 patients also had BCL2 rearrangements (double-hit NHL). No patients underwent autologous stem cell transplantation in first remission. For all myc-positive patients, the median PFS was 16.6 months, and the median OS was 37.7 months. For patients who had double-hit NHL, the median PFS was 8 months, and the median OS was 12.5 months; whereas the median PFS and OS were not reached for myc-positive patients. A complete response (CR) after front-line therapy, the presence of t(14;18), International Prognostic Index (IPI) group, and age were associated with PFS; whereas only the achievement of a CR and age >60 years were associated with OS in the multivariable setting. The median PFS was 3.3 months, and the median and OS was 7.0 months for patients who did not attain a CR; and the medians were not reached for patients who achieved a CR (P < .00001).

CONCLUSIONS

The achievement of a CR with front-line therapy is associated with a prolonged PFS and OS in patients with myc-positive NHL, even after adjusting for type of initial therapy, histology, age, IPI, or the presence of a concurrent BCL2 translocation.

BCL2, BCL6, IGH, TP53, and MYC protein expression and gene rearrangements as prognostic markers in diffuse large B-cell lymphoma: a study of 44 Turkish patients

The purpose of this study was to determine the frequency of BCL2, BCL6, IGH, TP53, and MYC protein expression and rearrangements of the respective genes in diffuse large B-cell lymphoma (DLBCL) patients and to assess their prognostic values. Samples from 44 patients with DLBCL were evaluated using fluorescence in situ hybridization and immunohistochemical analyses. BCL6 was the most rearranged gene (63.6%), followed by MYC (31.8%), TP53 (22.7%), and BCL2 (18.2%). Multiple rearrangements were detected in 40.9% of the cases. BCL6 was the most expressed protein (78.6%), followed by TP53 (69.04%), BCL2 (59.5%) and MYC (14.3%). Expression of multiple proteins was detected in 67.4% of the cases. BCL2 (P = .003) expression had a significant negative influence on overall survival,whereas BCL6 (P = .014) expression had a significant positive influence. Our results with a different pattern of gene rearrangements and associated protein overexpression indicate the molecular genetic complexity of DLBCLs, which reflects the morphologic, biologic, and clinical heterogeneity of these lymphomas.

Immunohistochemistry for myc predicts survival in colorectal cancer

MYC over-expression as determined by molecular means has been reported as a favorable prognostic biomarker in colorectal carcinoma (CRC). However MYC expression analysis is not available in the routine clinical setting. We investigated whether immunohistochemistry (IHC) for the myc protein using a novel commercially available rabbit monoclonal antibody [clone Y69] which is currently in widespread clinical use for lymphoma diagnosis could be used to predict outcome in resected CRC. Myc IHC was performed on a tissue microarray (TMA) comprising a retrospective cohort of 1421 CRC patients and scored blinded as to all clinical and pathological data. IHC was also performed on a subcohort of whole section CRCs to assess staining characteristics and concordance with TMA expression. MYC over-expression was found in 980 (69%) of CRCs and was associated with tumor stage and DNA mismatch repair/BRAF status. There was substantial agreement between TMA and whole section myc IHC (kappa = 0.742, p<0.01). CRCs with MYC over-expression demonstrated improved 5-year survival (93.2% vs. 57.3%), with the effect significantly modulated by the dominant effect of tumor stage, age at diagnosis and lymphovascular space invasion status on survival. We conclude that myc status as determined by IHC alone can be used to predict overall survival in patients with CRC undergoing surgical resection.

Systems biology of primary CNS lymphoma: from genetic aberrations to modeling in mice

Primary lymphoma of the central nervous system (CNS, PCNSL) is a specific diffuse large B cell lymphoma entity arising in and confined to the CNS. Despite extensive research since many decades, the pathogenetic mechanisms underlying the remarkable tropism of this peculiar malignant hematopoietic tumor remain still to be elucidated. In the present review, we summarize the present knowledge on the genotypic and phenotypic characteristics of the tumor cells of PCNSL, give an overview over deregulated molecular pathways in PCNSL and present recent progress in the field of preclinical modeling of PCNSL in mice. With regard to the phenotype, PCNSL cells resemble late germinal center exit IgM+IgD+ B cells with blocked terminal B cell differentiation. They show continued BCL6 activity in line with ongoing activity of the germinal center program. This together with the pathways deregulated by genetic alterations may foster B cell activation and brisk proliferation, which correlated with the simultaneous MYC and BCL2 overexpression characteristic for PCNSL. On the genetic level, PCNSL are characterized by ongoing aberrant somatic hypermutation that, besides the IG locus, targets the PAX5, TTF, MYC, and PIM1 genes. Moreover, PCNSL cells show impaired IG class switch due to sμ region deletions, and PRDM1 mutations. Several important pathways, i.e., the B cell receptor (BCR), the toll-like receptor, and the nuclear factor-κB pathway, are activated frequently due to genetic changes affecting genes like CD79B, SHIP, CBL, BLNK, CARD11, MALT1, BCL2, and MYD88. These changes likely foster tumor cell survival. Nevertheless, many of these features are also present in subsets of systemic DLBLC and might not be the only reasons for the peculiar tropism of PCNSL. Here, preclinical animal models that closely mimic the clinical course and neuropathology of human PCNSL may provide further insight and we discuss recent advances in this field. Such models enable us to understand the pathogenetic interaction between the malignant B cells, resident cell populations of the CNS, and the associated inflammatory infiltrate. Indeed, the immunophenotype of the CNS as well as tumor cell characteristics and intracerebral interactions may create a micromilieu particularly conducive to PCNSL that may foster aggressiveness of tumor cells and accelerate the fatal course of disease. Suitable animal models may also serve as a well-defined preclinical system and may provide a useful tool for developing new specific therapeutic strategies.

Both leukaemic and normal peripheral B lymphoid cells are highly sensitive to the selective pharmacological inhibition of prosurvival Bcl-2 with ABT-199

Overexpression of the prosurvival protein Bcl-2 marks many B-lymphoid malignancies and contributes to resistance to many commonly used chemotherapeutic agents. The first effective BH3 mimetic inhibitors of Bcl-2, ABT-737 and navitoclax, also target Bcl-xL, causing dose-limiting thrombocytopenia. This prompted the development of the Bcl-2-selective antagonist, ABT-199. Here we show that in lymphoid cells, ABT-199 specifically causes Bax/Bak-mediated apoptosis that is triggered principally by the initiator BH3-only protein Bim. As expected, malignant cells isolated from patients with chronic lymphocytic leukaemia are highly sensitive to ABT-199. However, we found that normal, untransformed mature B cells are also highly sensitive to ABT-199, both in vitro and in vivo. By contrast, the B-cell precursors are largely spared, as are cells of myeloid origin. These results pinpoint the probable impact of the pharmacological inhibition of Bcl-2 by ABT-199 on the normal mature haemopoietic cell lineages in patients, and have implications for monitoring during ABT-199 therapy as well as for the clinical utility of this very promising targeted agent.

Diffuse large B-cell lymphoma-treatment approaches in the molecular era

Diffuse large B-cell lymphoma (DLBCL) is an aggressive B-cell non-Hodgkin lymphoma that affects patients of all ages with a wide range of clinical presentations. Although DLBCL is curable even in advanced stages, up to one-third of patients will not achieve cure with initial therapy. In the modern era of rituximab-based therapy as the first-line treatment, the prognoses of patients who require salvage therapy are poor and most will eventually succumb to their disease. Insight into the complex molecular circuitry of DLBCL reveals a diverse range of somatic mutations and aberrant intracellular signalling pathways that characterize distinct molecular subsets of the disease. The next major breakthrough in DLBCL therapy during this 'molecular era' of disease definition will be the identification of combinations of novel agents that target the oncogenic drivers of these subsets. Well-conducted clinical trials, with translational molecular investigations, will be essential to achieve the goal of precision medicine and expand the number of patients with DLBCL who achieve a cure.

Management of B-cell non-Hodgkin lymphoma in Asia: resource-stratified guidelines

Treatment of B-cell non-Hodgkin lymphomas has undergone substantial developments in the past 10 years. The introduction of rituximab has greatly improved survival outcomes in patients. Clinical practice guidelines based on current evidence have been developed to provide recommendations for standard treatment approaches. However, guidelines do not take into account resource limitations in resource-poor countries. The huge disparities in economy, health-care infrastructure, and access to novel drugs between Asian countries can hinder the delivery of optimum care to patients with lymphoma in Asia. We outline guidelines appropriate to different levels of health-care resources and expertise, aiming to provide advice on diagnosis and treatment, unify interpretation of results, and allow the design of future studies in Asia. In this resource-adapted consensus, we summarise recommendations for diagnosis, staging, risk stratification, and treatment of common B-cell non-Hodgkin lymphomas in Asia.

Discovery and characterization of super-enhancer-associated dependencies in diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is a biologically heterogeneous and clinically aggressive disease. Here, we explore the role of bromodomain and extra-terminal domain (BET) proteins in DLBCL, using integrative chemical genetics and functional epigenomics. We observe highly asymmetric loading of bromodomain 4 (BRD4) at enhancers, with approximately 33% of all BRD4 localizing to enhancers at 1.6% of occupied genes. These super-enhancers prove particularly sensitive to bromodomain inhibition, explaining the selective effect of BET inhibitors on oncogenic and lineage-specific transcriptional circuits. Functional study of genes marked by super-enhancers identifies DLBCLs dependent on OCA-B and suggests a strategy for discovering unrecognized cancer dependencies. Translational studies performed on a comprehensive panel of DLBCLs establish a therapeutic rationale for evaluating BET inhibitors in this disease.

Treatment strategies for aggressive lymphomas: what works?

Over the past 30 years, many treatment platforms have been developed for diffuse large B-cell lymphoma, but none proved better than CHOP (cyclophosphamide, hydroxydaunorubicin, vincristine, prednisone/prednisolone). In the immunochemotherapy era, however, there is convincing evidence for superior chemotherapy platforms. A randomized study from the Groupe d'Etude des Lymphomes de l'Adulte showed that R-ACVBP (rituximab plus doxorubicin, cyclophosphamide, vindesine, bleomycin, prednisone) was superior to rituximab plus CHOP (R-CHOP) in patients under 60 years of age, but toxicity limits its use to younger patients. Studies also suggest that DA-EPOCH-R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab) is more effective in some subtypes of diffuse large B-cell lymphoma and a randomized comparison with R-CHOP is now nearing completion. The simplicity and safety of R-CHOP and the long history of failed contenders, however, has set a high bar for new approaches.

MYC translocation partner gene determines survival of patients with large B-cell lymphoma with MYC- or double-hit MYC/BCL2 translocations

In large B-cell lymphoma (LBCL) MYC- and MYC/BCL2 double-hit (DH) translocations have been associated with inferior survival. We hypothesised that the negative prognostic impact of MYC translocation was determined by an immunoglobulin MYC translocation partner gene (IG-MYC), as opposed to a non-immunoglobulin partner gene (nonIG-MYC). In a prospective, unselected cohort of 237 LBCL patients MYC and BCL2 translocations were identified by fluorescent in situ hybridisation (FISH) with split probes. MYC translocation partner gene was identified by IGH/MYC fusion probes and/or kappa/lambda split probes. Clinical data were collected from patient files. MYC translocation was identified in 28/225 patients. IG-MYC translocation partner gene was identified in 12/24 patients. DH translocation was identified in 23/228 patients. IG-MYC translocation partner gene was identified in 9/19 DH patients. Neither MYC-nor DH translocation showed correlation with survival. However, MYC translocation with IG-MYC translocation partner gene was associated with worse OS compared with both MYC translocation with nonIG-MYC translocation partner gene (P = 0.02) as well as absence of MYC translocation (P = 0.03). In patients with DH a similar, however, stronger correlation was seen (P = 0.003 and P = 0.0004 respectively). MYC - or DH translocation with nonIG-MYC translocation partner gene was not associated with worse overall survival (P = 0.2 and P = 0.3 respectively). Most patients received Rituximab (86%) and CHOP/CHOP-like chemotherapy regimes (81%). We suggest that prognostic stratification of LBCL patients by MYC and/or DH translocations should include identification of MYC translocation partner gene because approximately half of the cases harbour nonIG-MYC translocation partner genes with no or minor influence on survival.

Autologous transplantation as consolidation for aggressive non-Hodgkin's lymphoma

BACKGROUND

The efficacy of autologous stem-cell transplantation during the first remission in patients with diffuse, aggressive non-Hodgkin's lymphoma classified as high-intermediate risk or high risk on the International Prognostic Index remains controversial and is untested in the rituximab era.

METHODS

We treated 397 patients who had disease with an age-adjusted classification of high risk or high-intermediate risk with five cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or CHOP plus rituximab. Patients with a response were randomly assigned to receive three additional cycles of induction chemotherapy (control group) or one additional cycle of induction chemotherapy followed by autologous stem-cell transplantation (transplantation group). The primary efficacy end points were 2-year progression-free survival and overall survival.

RESULTS

Of 370 induction-eligible patients, 253 were randomly assigned to the transplantation group (125) or the control group (128). Forty-six patients in the transplantation group and 68 in the control group had disease progression or died, with 2-year progression-free survival rates of 69 and 55%, respectively (hazard ratio in the control group vs. the transplantation group, 1.72; 95% confidence interval [CI], 1.18 to 2.51; P=0.005). Thirty-seven patients in the transplantation group and 47 in the control group died, with 2-year overall survival rates of 74 and 71%, respectively (hazard ratio, 1.26; 95% CI, 0.82 to 1.94; P=0.30). Exploratory analyses showed a differential treatment effect according to risk level for both progression-free survival (P=0.04 for interaction) and overall survival (P=0.01 for interaction). Among high-risk patients, the 2-year overall survival rate was 82% in the transplantation group and 64% in the control group.

CONCLUSIONS

Early autologous stem-cell transplantation improved progression-free survival among patients with high-intermediate-risk or high-risk disease who had a response to induction therapy. Overall survival after transplantation was not improved, probably because of the effectiveness of salvage transplantation. (Funded by the National Cancer Institute, Department of Health and Human Services, and others; SWOG-9704 ClinicalTrials.gov number, NCT00004031.).

Biological characterization of adult MYC-translocation-positive mature B-cell lymphomas other than molecular Burkitt lymphoma

Chromosomal translocations affecting the MYC oncogene are the biological hallmark of Burkitt lymphomas but also occur in a subset of other mature B-cell lymphomas. If accompanied by a chromosomal break targeting the BCL2 and/or BCL6 oncogene these MYC translocation-positive (MYC(+)) lymphomas are called double-hit lymphomas, otherwise the term single-hit lymphomas is applied. In order to characterize the biological features of these MYC(+) lymphomas other than Burkitt lymphoma we explored, after exclusion of molecular Burkitt lymphoma as defined by gene expression profiling, the molecular, pathological and clinical aspects of 80 MYC-translocation-positive lymphomas (31 single-hit, 46 double-hit and 3 MYC(+)-lymphomas with unknown BCL6 status). Comparison of single-hit and double-hit lymphomas revealed no difference in MYC partner (IG/non-IG), genomic complexity, MYC expression or gene expression profile. Double-hit lymphomas more frequently showed a germinal center B-cell-like gene expression profile and had higher IGH and MYC mutation frequencies. Gene expression profiling revealed 130 differentially expressed genes between BCL6(+)/MYC(+) and BCL2(+)/MYC(+) double-hit lymphomas. BCL2(+)/MYC(+) double-hit lymphomas more frequently showed a germinal center B-like gene expression profile. Analysis of all lymphomas according to MYC partner (IG/non-IG) revealed no substantial differences. In this series of lymphomas, in which immunochemotherapy was administered in only a minority of cases, single-hit and double-hit lymphomas had a similar poor outcome in contrast to the outcome of molecular Burkitt lymphoma and lymphomas without the MYC break. Our data suggest that, after excluding molecular Burkitt lymphoma and pediatric cases, MYC(+) lymphomas are biologically quite homogeneous with single-hit and double-hit lymphomas as well as IG-MYC and non-IG-MYC(+) lymphomas sharing various molecular characteristics.

Autologous transplantation as consolidation for aggressive non-Hodgkin's lymphoma

BACKGROUND

The efficacy of autologous stem-cell transplantation during the first remission in patients with diffuse, aggressive non-Hodgkin's lymphoma classified as high-intermediate risk or high risk on the International Prognostic Index remains controversial and is untested in the rituximab era.

METHODS

We treated 397 patients who had disease with an age-adjusted classification of high risk or high-intermediate risk with five cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or CHOP plus rituximab. Patients with a response were randomly assigned to receive three additional cycles of induction chemotherapy (control group) or one additional cycle of induction chemotherapy followed by autologous stem-cell transplantation (transplantation group). The primary efficacy end points were 2-year progression-free survival and overall survival.

RESULTS

Of 370 induction-eligible patients, 253 were randomly assigned to the transplantation group (125) or the control group (128). Forty-six patients in the transplantation group and 68 in the control group had disease progression or died, with 2-year progression-free survival rates of 69 and 55%, respectively (hazard ratio in the control group vs. the transplantation group, 1.72; 95% confidence interval [CI], 1.18 to 2.51; P=0.005). Thirty-seven patients in the transplantation group and 47 in the control group died, with 2-year overall survival rates of 74 and 71%, respectively (hazard ratio, 1.26; 95% CI, 0.82 to 1.94; P=0.30). Exploratory analyses showed a differential treatment effect according to risk level for both progression-free survival (P=0.04 for interaction) and overall survival (P=0.01 for interaction). Among high-risk patients, the 2-year overall survival rate was 82% in the transplantation group and 64% in the control group.

CONCLUSIONS

Early autologous stem-cell transplantation improved progression-free survival among patients with high-intermediate-risk or high-risk disease who had a response to induction therapy. Overall survival after transplantation was not improved, probably because of the effectiveness of salvage transplantation. (Funded by the National Cancer Institute, Department of Health and Human Services, and others; SWOG-9704 ClinicalTrials.gov number, NCT00004031.).

Prognostic significance of immunohistochemistry-based markers and algorithms in immunochemotherapy-treated diffuse large B cell lymphoma patients

AIMS

To reassess the prognostic validity of immunohistochemical markers and algorithms identified in the CHOP era in immunochemotherapy-treated diffuse large B cell lymphoma patients.

METHODS AND RESULTS

The prognostic significance of immunohistochemical markers (CD10, Bcl-6, Bcl-2, MUM1, Ki-67, CD5, GCET1, FoxP1, LMO2) and algorithms (Hans, Hans*, Muris, Choi, Choi*, Nyman, Visco-Young, Tally) was assessed using clinical diagnostic blocks taken from an unselected, population-based cohort of 190 patients treated with R-CHOP. Dichotomizing expression, low CD10 (<10%), low LMO2 (<70%) or high Bcl-2 (≥80%) predicted shorter overall survival (OS; P = 0.033, P = 0.010 and P = 0.008, respectively). High Bcl-2 (≥80%), low Bcl-6 (<60%), low GCET1 (<20%) or low LMO2 (<70%) predicted shorter progression-free survival (PFS; P = 0.001, P = 0.048, P = 0.045 and P = 0.002, respectively). The Hans, Hans* and Muris classifiers predicted OS (P = 0.022, P = 0.037 and P = 0.011) and PFS (P = 0.021, P = 0.020 and P = 0.004). The Choi, Choi* and Tally were associated with PFS (P = 0.049, P = 0.009 and P = 0.023). In multivariate analysis, the International Prognostic Index (IPI) was the only independent predictor of outcome (OS; HR: 2.60, P < 0.001 and PFS; HR: 2.91, P < 0.001).

CONCLUSIONS

Results highlight the controversy surrounding immunohistochemistry-based algorithms in the R-CHOP era. The need for more robust markers, applicable to the clinic, for incorporation into improved prognostic systems is emphasized.

MYC chromosomal aberration in differential diagnosis between Burkitt and other aggressive lymphomas

Myc oncogenetic deregulation is abundantly described in several solid human cancer and lymphomas. Particularly, Burkitt's lymphoma belongs to the family of B Non Hodgkin aggressive lymphomas. Although it is morphologically characterized, immunophenotypic and cytogenetic diagnosis remains complex. In 2008, the WHO has introduced a new diagnostic class of aggressive B-cell lymphomas with features intermediate between BL and DLBCL. This diagnostic class represents a temporary container of aggressive B-cell lymphomas, not completely belonging to the BL and DLBCL categories. The importance of establishing a correct diagnosis would allow a better prognostic classification and a better therapeutic approach. In this review, we summarize the main diagnostic approaches necessary for appropriate diagnoses and we emphasize the importance of cytogenetic analysis of the oncogene Myc in the histopathological diagnosis and the prognostic/predictive stratification. In this contest, Myc represents the more involved gene in the development of these lymphomas. Therefore, we analyze the genetic aberrations causing its over-expression and the concomitant deregulation of molecular pathways related to it. We also propose a FISH approach useful in the diagnosis of these lymphomas.

Molecular classification, pathway addiction, and therapeutic targeting in diffuse large B cell lymphoma

The rapid emergence of molecularly based techniques to detect changes in the genetic landscape of diffuse large B cell lymphoma (DLBCL), including gene expression, DNA and RNA sequencing, and epigenetic profiling, has significantly influenced the understanding and therapeutic targeting of DLBCL. In this review, we briefly discuss the new methods used in the study of DLBCL. We describe the influence of the generated data on DLBCL classification and the identification of new entities and altered cell survival strategies, with a focus on the renewed interest in some classic oncogenic pathways that are currently targeted for new therapy. Finally, we examine the molecular genomic studies that revealed the importance of the tumor microenvironment in the pathogenesis of DLBCL.

Phase II study of alisertib, a selective Aurora A kinase inhibitor, in relapsed and refractory aggressive B- and T-cell non-Hodgkin lymphomas

PURPOSE

Aurora A kinase (AAK) is overexpressed in aggressive lymphomas and can correlate with more histologically aggressive forms of disease. We therefore designed a phase II study of alisertib, a selective AAK inhibitor, in patients with relapsed and refractory aggressive non-Hodgkin lymphomas.

PATIENTS AND METHODS

Patients age ≥ 18 years were eligible if they had relapsed or refractory diffuse large B-cell lymphoma (DLBCL), mantle-cell lymphoma (MCL), transformed follicular lymphoma, Burkitt's lymphoma, or noncutaneous T-cell lymphoma. Alisertib was administered orally at 50 mg twice daily for 7 days in 21-day cycles.

RESULTS

We enrolled 48 patients. Histologies included DLBCL (n = 21), MCL (n = 13), peripheral T-cell lymphoma (n = 8), transformed follicular lymphoma (n = 5), and Burkitt's (n = 1). Most common grade 3 to 4 adverse events were neutropenia (63%), leukopenia (54%), anemia (35%), thrombocytopenia (33%), stomatitis (15%), febrile neutropenia (13%), and fatigue (6%). Four deaths during the study were attributed to progressive non-Hodgkin lymphoma (n = 2), treatment-related sepsis (n = 1), and unknown cause (n = 1). The overall response rate was 27%, including responses in three of 21 patients with DLBCL, three of 13 with MCL, one of one with Burkitt's lymphoma, two of five with transformed follicular lymphoma, and four of eight with noncutaneous T-cell lymphoma. The alisertib steady-state trough concentration (n = 25) revealed the expected pharmacokinetic variability, with a trend for higher incidence of adverse event-related dose reductions at higher trough concentrations. Analysis for AAK gene amplification and total AAK protein revealed no differences between histologies or correlation with clinical response.

CONCLUSION

The novel AAK inhibitor alisertib seems clinically active in both B- and T-cell aggressive lymphomas. On the basis of these results, confirmatory single-agent and combination studies have been initiated.

Understanding MYC-driven aggressive B-cell lymphomas: pathogenesis and classification

MYC is a potent oncogene initially identified as the target of the t(8;14)(q24;q32) chromosome translocation in Burkitt lymphoma. MYC gene alterations have been identified in other mature B-cell neoplasms that are usually associated with an aggressive clinical behavior. Most of these tumors originate in cells that do not normally express MYC protein. The oncogenic events leading to MYC up-regulation seem to overcome the inhibitory effect of physiological repressors such as BCL6 or BLIMP1. Aggressive lymphomas frequently carry additional oncogenic alterations that cooperate with MYC dysregulation, likely counteracting its proapoptotic function. The development of FISH probes and new reliable antibodies have facilitated the study of MYC gene alterations and protein expression in large series of patients, providing new clinical and biological perspectives regarding MYC dysregulation in aggressive lymphomas. MYC gene alterations in large B-cell lymphomas are frequently associated with BCL2 or BCL6 translocations conferring a very aggressive behavior. Conversely, MYC protein up-regulation may occur in tumors without apparent gene alterations, and its association with BCL2 overexpression also confers a poor prognosis. In this review, we integrate all of this new information and discuss perspectives, challenges, and open questions for the diagnosis and management of patients with MYC-driven aggressive B-cell lymphomas.

[Lymph node pathology - an update]

Immune suppression is a risk factor for malignant lymphoma development. Progress in medical science has increased the numbers of immunosuppressed patients due to organ transplantations or successful treatment of autoimmune diseases. Different forms of immune suppression and the respective lymphoma entities are discussed in this article. Another issue treated are gray zone lymphomas between Hodgkin's lymphoma and diffuse large B cell lymphoma. This category not only represents a diagnostic challenge but also represents more a true biological continuum.

Lymphoma and myeloma cells are highly sensitive to growth arrest and apoptosis induced by artesunate

OBJECTIVES

The use of new drugs has improved the treatment of multiple myeloma and diffuse large B-cell lymphoma (DLBCL). Nevertheless, over time many patients relapse and develop resistance to treatment, and efforts are needed to overcome drug resistance. The widely used malaria drug artesunate has been reported to have antitumor activity, and we aimed to test the effects of artesunate on a panel of myeloma and lymphoma cells.

METHODS

Myeloma and DLBCL cell lines were treated with artesunate in vitro. The effects of artesunate treatment were evaluated using ATP content measurements for proliferation and annexin V/propidium iodide labeling for apoptosis. Western blotting was used to look for artesunate-induced protein changes. In addition, we measured artesunate effects on patient myeloma cells in the presence of bone marrow stromal cells.

RESULTS

Artesunate treatment efficiently inhibited cell growth and induced apoptosis in cell lines. Apoptosis was induced concomitantly with downregulation of MYC and anti-apoptotic Bcl-2 family proteins, as well as with cleavage of caspase-3. The IC50 values of artesunate in cell lines varied between 0.3 and 16.6 μm. Furthermore, some primary myeloma cells were also sensitive to artesunate at doses around 10 μm. Concentrations of this order are pharmacologically relevant as they can be obtained in plasma after intravenous administration of artesunate for malaria treatment.

CONCLUSION

Our findings indicate that artesunate is a potential drug for treatment of multiple myeloma and DLBCL at doses of the same order as currently in use for treatment of malaria without serious adverse effects.

Immunohistochemical evaluation of MYC expression in mantle cell lymphoma

AIM

To assess the validity and potential clinical utility of evaluating MYC expression by immunohistochemistry (IHC) in mantle cell lymphoma (MCL).

METHODS AND RESULTS

MYC IHC was scored on a tissue microarray containing 62 MCLs and 29 controls by two pathologists. Inter-observer correlation was high (intra-class correlation of 0.98). MYC IHC scores correlated with MYC expression (Spearman's rank correlation 0.69, P < 0.0001) and weakly with Ki67 proliferation index (Spearman's rank correlation 0.30, P = 0.03). Six blastic MCLs did not have higher mean MYC IHC scores or MYC mRNA expression than non-blastic MCLs. None of 57 cases assessed, including all of the blastic cases, showed MYC rearrangement by fluorescence in-situ hybridization. Multivariate analysis with backward selection from potential predictors including age, lactate dehydrogenase, leukocyte count, MIPI score, ECOG performance status, blastic morphology and Ki67 index showed that MYC IHC score is an independent predictor of progression-free survival (hazard ratio 2.34, 95% CI 1.42-3.88, P = 0.0009) and overall survival (hazard ratio 1.90, 95% CI 1.05-3.43, P = 0.034).

CONCLUSIONS

We show that a new monoclonal anti-MYC antibody can enable accurate and reproducible visual assessment of MYC expression that is independently predictive of clinical outcomes in MCL.

A model of sensitivity and resistance to histone deacetylase inhibitors in diffuse large B cell lymphoma: Role of cyclin-dependent kinase inhibitors

Diffuse large B cell lymphoma (DLBCL) is an aggressive form of non-Hodgkin lymphoma. While the initial treatment strategy is highly effective, relapse occurs in 40% of cases. Histone deacetylase inhibitors (HDACi) are a promising class of anti-cancer drugs but their single agent efficacy against relapsed DLBCL has been variable, ranging from few complete/partial responses to some stable disease. However, most patients showed no response to HDACi monotherapy for unknown reasons. Here we show that sensitivity and resistance to the hydroxamate HDACi, PXD101, can be modeled in DLBCL cell lines. Sensitivity is characterized by G₂/M arrest and apoptosis and resistance by reversible G₁ growth arrest. These responses to PXD101 are independent of several negative prognostic indicators such as DLBCL subtype, BCL2 and MYC co-expression, and p53 mutation, suggesting that HDACi might be used effectively against highly aggressive DLBCL tumors if they are combined with other therapeutics that overcome HDACi resistance. Our investigation of mechanisms underlying HDACi resistance showed that cyclin-dependent kinase inhibitors (CKIs), p21 and p27, are upregulated by PXD101 in a sustained fashion in resistant cell lines concomitant with decreased activity of the cyclin E/cdk2 complex and decreased Rb phosphorylation. PXD101 treatment results in increased association of CKI with the cyclin E/cdk2 complex in resistant cell lines but not in a sensitive line, indicating that the CKIs play a key role in G₁ arrest. The results suggest several treatment strategies that might increase the efficacy of HDACi against aggressive DLBCL.

Myc and mTOR converge on a common node in protein synthesis control that confers synthetic lethality in Myc-driven cancers

Myc is one of the most commonly deregulated oncogenes in human cancer, yet therapies directly targeting Myc hyperactivation are not presently available in the clinic. The evolutionarily conserved function of Myc in modulating protein synthesis control is critical to the Myc oncogenic program. Indeed, enhancing the protein synthesis capacity of cancer cells directly contributes to their survival, proliferation, and genome instability. Therefore, inhibiting enhanced protein synthesis may represent a highly relevant strategy for the treatment of Myc-dependent human cancers. However, components of the translation machinery that can be exploited as therapeutic targets for Myc-driven cancers remain poorly defined. Here, we uncover a surprising and important functional link between Myc and mammalian target of rapamycin (mTOR)-dependent phosphorylation of eukaryotic translation initiation factor 4E binding protein-1 (4EBP1), a master regulator of protein synthesis control. Using a pharmacogenetic approach, we find that mTOR-dependent phosphorylation of 4EBP1 is required for cancer cell survival in Myc-dependent tumor initiation and maintenance. We further show that a clinical mTOR active site inhibitor, which is capable of blocking mTOR-dependent 4EBP1 phosphorylation, has remarkable therapeutic efficacy in Myc-driven hematological cancers. Additionally, we demonstrate the clinical implications of these results by delineating a significant link between Myc and mTOR-dependent phosphorylation of 4EBP1 and therapeutic response in human lymphomas. Together, these findings reveal that an important mTOR substrate is found hyperactivated downstream of Myc oncogenic activity to promote tumor survival and confers synthetic lethality, thereby revealing a unique therapeutic approach to render Myc druggable in the clinic.

MYC protein expression and genetic alterations have prognostic impact in patients with diffuse large B-cell lymphoma treated with immunochemotherapy

MYC alterations influence the survival of patients with diffuse large B-cell lymphoma. Most studies have focused on MYC translocations but there is little information regarding the impact of numerical alterations and protein expression. We analyzed the genetic alterations and protein expression of MYC, BCL2, BCL6, and MALT1 in 219 cases of diffuse large B-cell lymphoma. MYC rearrangement occurred as the sole abnormality (MYC single-hit) in 3% of cases, MYC and concurrent BCL2 and/or BCL6 rearrangements (MYC double/triple-hit) in 4%, MYC amplifications in 2% and MYC gains in 19%. MYC single-hit, MYC double/triple-hit and MYC amplifications, but not MYC gains or other gene rearrangements, were associated with unfavorable progression-free survival and overall survival. MYC protein expression, evaluated using computerized image analysis, captured the unfavorable prognosis of MYC translocations/amplifications and identified an additional subset of patients without gene alterations but with similar poor prognosis. Patients with tumors expressing both MYC/BCL2 had the worst prognosis, whereas those with double-negative tumors had the best outcome. High MYC expression was associated with shorter overall survival irrespectively of the International Prognostic Index and BCL2 expression. In conclusion, MYC protein expression identifies a subset of diffuse large B-cell lymphoma with very poor prognosis independently of gene alterations and other prognostic parameters.

The histological and biological spectrum of diffuse large B-cell lymphoma in the World Health Organization classification

Diffuse large B-cell lymphomas (DLBCLs) are aggressive B-cell lymphomas that are clinically, pathologically, and genetically diverse, in part reflecting the functional diversity of the B-cell system. The focus in recent years has been toward incorporation of clinical features, morphology, immunohistochemistry, and ever evolving genetic data into the classification scheme. The 2008 World Health Organization classification reflects this complexity with the addition of several new entities and variants. The discovery of distinct subtypes by gene expression profiling heralded a new era with a focus on pathways of transformation as well as a promise of more targeted therapies, directed at specific pathways. Some DLBCLs exhibit unique clinical characteristics with a predilection for specific anatomic sites; the anatomic site often reflects underlying biological distinctions. Recently, the spectrum of Epstein-Barr virus (EBV)-driven B-cell proliferations in patients without iatrogenic or congenital immunosuppression has been better characterized; most of these occur in patients of advanced age and include Epstein-Barr virus (EBV)-positive large B-cell lymphoma of the elderly. Human herpesvirus 8 is involved in the pathogenesis of primary effusion lymphoma, which can present as a "solid variant." Two borderline categories were created; one deals with tumors at the interface between classic Hodgkin lymphoma and DLBCL. The second confronts the interface between Burkitt lymphoma and DLBCL, so-called "B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma" in the 2008 classification. Most cases harbor both MYC and BCL2 translocations and are highly aggressive. Another interesting entity is anaplastic lymphoma kinase-positive DLBCL, which renders itself potentially targetable by anaplastic lymphoma kinase inhibitors. Ongoing investigations at the genomic level, with both exome and whole-genome sequencing, are sure to reveal new pathways of transformation in the future.

Improving survival and preventing recurrence of diffuse large B-cell lymphoma in younger patients: current strategies and future directions

Prognosis of diffuse large B-cell lymphoma (DLBCL) has considerably improved during the last decade, mainly due to the addition of rituximab to chemotherapy. However, a significant proportion of patients still experience primary refractory disease or short-term relapses, conferring poor survival. Thus, achieving first-line complete remission is of major importance, especially in young and fit patients. Current strategies are based on the age-adapted International Prognostic Index, which separates patients into three prognostic subgroups (low-risk, intermediate-risk, and high-risk). However, it is based only on clinical variables, and we have learned from daily practice that there remains a marked heterogeneity within each subgroup. Recently, biological prognostic factors have emerged, and should now be part of initial evaluation to guide treatment. Among those, so-called double-hit DLBCL with deregulation of both MYC and BCL2 genes usually follows a particularly aggressive course and should be treated more intensively. But for many other patients, the indication of high-dose therapy rather than immunochemotherapy alone remains controversial. In these cases, the interest of an early ¹⁸F fluoro-2-deoxy-d-glucose positron emission tomography evaluation-based strategy is now being assessed in ongoing clinical trials. Moreover, other strategies to improve response and survival consist in adding novel agents to standard chemotherapy. In this field, newly developed anti-CD20 monoclonal antibodies and immunomodulatory drugs could be of particular interest during induction therapy to optimize the quality of response, but also in maintenance treatment, in order to decrease the risk of relapse. Only well-conducted clinical trials will be able to resolve all these issues. Therefore, physicians should be encouraged, as far as possible, to propose them to their patients.

[Grey zone lymphomas: limitations of the classification of aggressive B-cell lymphomas]

Grey zone lymphomas are lymphatic tumors that cannot be assigned to a defined lymphoma entity due to morphological, clinical or genetic reasons. As a defining criterion they present with features of two overlapping entities or features that are intermediate. Such lymphomas may represent a grey zone in the differentiation between indolent and aggressive lymphomas. Often they may show morphological features of one entity but be more related to another entity with respect to the immunophenotype and/or genetic constitution, such as lymphomas in the grey zone between primary mediastinal large B-cell lymphoma and primary nodal diffuse large B-cell lymphoma. The B-cell lymphoma, unclassified, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma has recently been recognized as a provisional category in the updated WHO 2008 classification of malignant lymphomas. This corresponds to a practical lymphoma category that obviously contains several entities with a Burkitt-like appearance and aggressive clinical behavior. Genetically, tumors in this category are frequently characterized by an atypical MYC translocation and complex karyotypic alterations. As yet, no adequate therapy concept exists.