Immunohistochemical and molecular characteristics with prognostic significance in diffuse large B-cell lymphoma

Identifying aggressive subsets within diffuse large B-cell lymphoma: implications for treatment approach

INTRODUCTION

While the majority of patients diagnosed with diffuse large B-cell lymphoma (DLBCL) can be cured with front-line chemoimmunotherapy, a subset of patients with high-risk disease remain challenging to treat. Identification of high-risk DLBCL is important as future therapy options are explored.

AREAS COVERED

We discuss the clinical, pathologic and molecular risk stratification in DLBCL and how these factors are incorporated into the decision making for the front-line therapy.

EXPERT OPINION

Clinical and pathological risk stratification has long been the standard for identifying likelihood of future disease progression and overall survival; however, these prediction models lack the granularity of individual patient pathology and response to therapy. Molecular subtypes defined through whole exome sequencing have independent prognostic significance. While identifying molecular drivers of aggressive disease has provided the opportunity to analyze novel therapy combinations with front-line chemoimmunotherapy, only modest benefit has been observed when targeting DLBCL subtypes. Combining clinical, pathologic, and molecular data will likely result in significant improvement in our ability to identify the most aggressive DLBCL subsets. Novel therapies and trial designs will continue to play an important role as we target these at-risk populations in the future.

Immunohistochemical Markers of Tumor Microenvironment as Prognostic Predictors in Diffuse Large B-Cell Lymphoma: Study from an Oncology Centre in South India

Introduction Diffuse large B-cell lymphoma (DLBCL) accounts for 60% of lymphomas in India. Although the survival of DLBCL patients has improved following the addition of rituximab, a subset of patients do not respond well to therapy. Among the several factors responsible for this varied response, tumor microenvironment is considered to be crucial. This study is a search for such prognostic markers in the tumor microenvironment.

Materials and Methods A total of 97 patients were selected, of whom 34 were treated with the CHOP regimen and 63 with RCHOP. Immunohistochemistry for CD68 was performed to study the stromal-1 signature and CD34 for stromal-2 signature.

Results There was a significant increase in the counts of CD68-positive cells among patients free of events. CD34 count was higher in patients with events in both CHOP and RCHOP groups.

Conclusion Additional assessment of stromal microenvironment along with the cell of origin might predict the clinical outcome better in DLBCL.

Epstein Barr Virus Infection Can be a Secondary Event in B-Cell Lymphomas: A Review of 338 Cases and a Novel Finding of Zonal EBER+ Tumor Cells Showing Features of Progression From Underlying EBV-negative Lymphoma

Cases of B-cell lymphoma over an 8-year interval with diagnosis of EBER positivity were retrieved from archives and reviewed for classification and pattern of Epstein Barr Virus (EBV) expression. Of 46 cases that were EBV early RNA (EBER)+ by in situ hybridization staining, 7 had nonuniform staining among the neoplastic cells. Four of those cases showed a uniform admixture of EBER+ and EBER- tumor cells, compatible with the prevailing theory of episomal EBV loss with cell replication. Three cases of lymphomas showed a partial and zonal pattern and other features suggest that EBV infection occurred after the lymphoma was already established. In case 1, an EBV-negative follicular lymphoma and an EBV+ diffuse large B-cell lymphoma (DLBCL) of activated B cell type were contiguous in a lymph node. Both components showed a BCL2 translocation by fluorescence in situ hybridization. In case 2, a DLBCL of germinal center type in an human immunodeficiency virus positive patient contained clusters of EBR+ lymphoma cells with Reed-Sternberg morphology and shift to an activated B-cell immunophenotype. In case 3, an ulcerated and perforated DLBCL in the stomach showed a superficial swath of EBER+ tumor cells accompanied by a relative absence of reactive T cells. In all 3 cases the tumor cells in EBER+ areas expressed latent membrane protein-1 and showed strong CD30 positivity. All 3 patients were treated with chemotherapy are currently in remission. Heterogenous EBER positivity has been reported previously in DLBCLs, attributed to loss of the episomal viral DNA from a subset of fully transformed tumor cells. Previously reported cases did not include description of zonation of EBV or phenotypic differences correlating with the presence of EBV. The cases reported here suggest that in a subset of EBV+ DLBCLs, EBV infection may not be the "first hit."

Prospective evaluation of flow cytometric characteristics, histopathologic diagnosis and clinical outcome in dogs with naïve B-cell lymphoma treated with a 19-week CHOP protocol

Canine B-cell lymphoma is a clinically heterogenous disease; however, it is generally treated as a single disease entity. The purpose of this clinical trial was to prospectively evaluate naïve canine B-cell lymphoma patients using histopathology, flow cytometry (FC) and a standardized chemotherapy protocol to better define subsets of this disease that may respond differently to treatment. Sixty-four dogs with naïve multicentric B-cell lymphoma were treated with a standardized 19-week CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy protocol. Most of the dogs (84.3%) were diagnosed with diffuse large B-cell lymphoma (DLBCL), followed by nodal marginal zone (7.8%), small B-cell (4.7%), Burkitt-like (1.6%) and follicular lymphoma (1.6%). FC confirmed the diagnosis of B-cell lymphoma in all cases. There were no clear phenotyping differences between the subtypes of B-cell lymphoma detectable by our FC panel. The histologic subtypes in this study exhibited a range of forward scatter values on flow cytometry, but all of the DLBCL cases were higher than a value of 469, while the only cases with a lower forward scatter value were follicular lymphoma and diffuse small B-cell lymphoma. Dogs with DLBCL had a significantly better objective response rate to the CHOP protocol (96.3%) than the non-DLBCL subtypes (70%, P = .024). The median progression-free survival time for patients with DLBCL (233 days) was significantly longer than that of all other histopathologic subgroups combined (163 days, P = .0005).

Prognostic values and clinical implications of programmed cell death-ligand 1 (PD-L1), fork head transcription factor P-1 (FOXP-1) and signal transducer and activator of transcription-3 (STAT-3) expression in diffuse large B-cell lymphoma (DLBCL); an immunohistochemical study

Context

PD-L1 is an inhibitory ligand that functions as an essential immune checkpoint. FOXP-1 is a member of the FOXP family. STAT-3 plays a critical role in regulation of cell proliferation and survival. The detailed expression of the three markers together in DLBCL tissues and their prognostic value in patients with DLBCL were not fully investigated.

Aim was to assess the expression of PD-L1, FOXP-1 and STAT-3 in diffuse large B-cell lymphoma (DLBCL) and to correlate their expression with the pathological findings, prognostic parameters and clinical implications of patients.

Methods

PD-L1, FOXP-1 and STAT-3 were assessed in DLBCL tissues derived from 50 patients using immunohistochemistry. Patients were followed up for 3 years for response to therapy progression, recurrence and survival.

Results

High PD-L1 expression was associated with bone marrow involvement (p = 0.004), extra-nodal involvement (p = 0.006) and advanced stage (p = 0.003). High FOXP-1 expression was associated with presence of bone marrow involvement and high risk group (p < 0.001). High STAT-3 expression was associated with older age of the patient (p < 0.001), presence of bone marrow involvement (p = 0.002), extra-nodal involvement (p = 0.009), and high risk group (p = 0.005). High expression of PD-L1, FOXP-1 and STAT-3 was related to poor response to therapy, poor OS rate and RFS rates (p < 0.001).

Conclusion

High expression of PD-L1, FOXP-1 and STAT-3 was related poor prognosis in DLBCL patients.

Venetoclax plus R- or G-CHOP in non-Hodgkin lymphoma: results from the CAVALLI phase 1b trial

Novel strategies, such as chemosensitization with targeted agents, that build on the success of standard immunochemotherapy show promise for the treatment of non-Hodgkin lymphoma (NHL). Here, we report a phase 1b study investigating dose escalation of the BCL2 inhibitor, venetoclax, in combination with rituximab or obinutuzumab and cyclophosphamide, doxorubicin, vincristine, and prednisone (R-/G-CHOP) chemotherapy in B-cell NHL. Objectives included safety assessment and determination of a recommended phase 2 dose (RP2D). Fifty-six patients were enrolled, most with follicular lymphoma (43%) or diffuse large B-cell lymphoma (DLBCL; 32%). Dose-limiting toxicities were reported in 3/14 patients at the first venetoclax dose (200 mg/d), after which dosing was changed from daily to 10 days per cycle and escalated to 800 mg. A further reduction to 5 days per cycle occurred at the 800-mg dose level in the G-CHOP arm. Cytopenias were predominant among grade 3/4 events and reported at a higher rate than expected, particularly in the G-CHOP arm; however, safety was manageable. Overall response rates were 87.5% (R-CHOP and G-CHOP combinations); complete response (CR) rates were 79.2% and 78.1%, respectively. Most double-expressor (BCL2⁺ and MYC⁺) DLBCL patients (87.5%; n = 7/8) achieved CR. Although the maximum tolerated dose was not reached, the RP2D for venetoclax with R-CHOP was established at 800 mg days 4 to 10 of cycle 1 and days 1 to 10 of cycles 2 to 8; higher doses were not explored, and this dosing schedule demonstrated an acceptable safety profile. This regimen is subsequently being evaluated in first-line DLBCL in the phase 2 portion of the study. This trial was registered at www.clinicaltrials.gov as #NCT02055820.

Clinical Significance of BCL2, C-MYC, and BCL6 Genetic Abnormalities, Epstein-Barr Virus Infection, CD5 Protein Expression, Germinal Center B Cell/Non-Germinal Center B-Cell Subtypes, Co-expression of MYC/BCL2 Proteins and Co-expression of MYC/BCL2/BCL6 Proteins in Diffuse Large B-Cell Lymphoma: A Clinical and Pathological Correlation Study of 120 Patients

Background: Clinical significance of germinal center B-cell (GCB) and non-GCB sub-categorization, expression of MYC, BCL2, BCL6, CD5 proteins and Epstein Barr virus encoded RNA (EBER) positivity in diffuse large B-cell lymphoma (DLBCL) remain controversial. Could these biomarkers accurately identify high risk DLBCL patients? Are MYC, BCL2 and BCL6 proteins expression feasible as baseline testing to predict c-Myc, BCL2 or BCL6 gene rearrangements? Aims: To investigate prognostic values of GCB/non-GCB sub-categorization, Double Protein Expression Lymphoma (DPL), Triple Protein Expression Lymphoma (TPL), positivity of CD5 protein and EBER in patients with DLBCL disease. To evaluate correlation between BCL2 , c-Myc and BCL6 gene rearrangements with BCL2, MYC and BCL6 proteins expression. Methods: Diagnostic tissue samples of 120 DLBCL patients between January 2012 to December 2013 from four major hospitals in Malaysia were selected. Samples were subjected to immunohistochemical staining, fluorescent in-situ hybridization (FISH) testing, and central pathological review. Pathological data were correlated with clinical characteristics and treatment outcome. Results: A total of 120 cases were analysed. Mean age of diagnosis was 54.1 years ± 14.6, 64 were males, 56 were females, mean follow up period was 25 months (ranged from 1 to 36 months). Of the 120 cases, 74.2% were non-GCB whereas 25.8% were GCB, 6.7% were EBER positive, 6.7% expressed CD5 protein, 13.3% were DPL and 40% were TPL. The prevalence of c-Myc, BCL2, BCL6 gene rearrangements were 5.8%, 5.8%, and 14.2%, respectively; and 1.6% were Double Hit Lymphoma (DHL). EBER positivity, DPL, TPL, c-Myc gene rearrangement, BCL2 gene rearrangement, extra copies of BCL2 gene and BCL6 gene rearrangement were associated with shorter median overall survival (P<0.05). IPI score was the significant determinants of median overall survival in DPL and TPL (P<0.05). CD5 protein expression and GCB/non-GCB sub-categorization did not affect treatment outcome (P>0.05). Overall, c-Myc, BCL2 and BCL6 gene rearrangements showed weak correlation with expression of MYC, BCL2 and BCL6 proteins (P>0.05). Fluorescent in situ hybridization is the preferred technique for prediction of treatment outcome in DLBCL patients. Conclusion: c-Myc, BCL2, and BCL6 gene rearrangements, EBER expression, DHL, TPL and IPI score are reliable risk stratification tools. MYC, BCL2 and BCL6 proteins expression are not applicable as baseline biomarkers to predict c-Myc, BCL2, and BCL6 gene rearrangements.

Inferior survival in high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements is not associated with MYC/IG gene rearrangements

High-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements (double-/triple-hit lymphoma) have an aggressive clinical course. We investigated the prognostic value of transformation from low-grade lymphoma, cytological features (high grade versus large cell), MYC rearrangement partners (immunoglobulin versus nonimmunoglobulin gene), and treatment. We evaluated 100 adults with double-/triple-hit lymphoma, reviewing cytological features; cell of origin; and rearrangements of MYC, BCL2, and BCL6 using MYC, BCL2, and BCL6 break-apart and IGH/MYC, IGL/MYC, IGK/MYC, and IGH/BCL2 dual-fusion interphase fluorescence in situ hybridization probes. Outcome analysis was restricted to patients with lymphoma, de novo or at transformation, who received anthracycline-based chemotherapy. Among them, 60% had high-grade cytological features; 91% had a germinal center B-cell phenotype, and 60% had a MYC/IG rearrangement. Germinal center B-cell phenotype was associated with BCL2 rearrangements (P<0.001). Mean (95% confidence interval) 5-year overall survival was 49% (37%–64%). Transformation from previously treated and untreated low-grade lymphoma was associated with inferior overall survival (hazard ratio, 2.99; P=0.008). Patients with high-grade cytological features showed a non-significant tendency to inferior outcome (hazard ratio, 2.32; P=0.09). No association was observed between MYC rearrangement partner and overall survival (hazard ratio, 1.00; P=0.99). Compared with patients receiving rituximab, cyclophosphamide, doxorubicin, and vincristine (R-CHOP) and dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (EPOCH-R), patients receiving rituximab, cyclophosphamide, vincristine, doxorubicin, methotrexate/ifosfamide, etoposide, and cytarabine (R-CODOX-M/IVAC) had a non-significant tendency to better overall survival (hazard ratio, 0.37; P=0.10). In conclusion, high-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements had heterogeneous outcomes and MYC/IG rearrangements were not associated with inferior overall survival.

A multicolour flow cytometric assay for c-MYC protein in B-cell lymphoma

AIM

Develop an objective assay to detect c-MYC protein expression using multiparametric flow cytometry (FCM) as an alternative to immunohistochemistry (IHC).

METHODS

57 patient samples and 11 cell line samples were evaluated. Cell suspensions were obtained and c-MYC staining was performed in combination with CD45 and CD19 and, in some samples, CD10. The percentage of c-MYC+ cells by FCM was correlated with the percentage determined by IHC. The relationship between c-MYC protein expression and the presence of a c-MYC gene rearrangement in aggressive and high-grade lymphomas was also assessed.

RESULTS

c-MYC expression by FCM and IHC demonstrated a high degree of correlation in a training set of 33 patient cases, r=0.92, 11 cell line samples, r=0.81 and in a validation set of 24 aggressive and high-grade B-cell lymphomas, r=0.85. c-MYC gene was rearranged by fluorescence in situ hybridisation in 6/9 samples with high c-MYC expression (>40%) by FCM and 6/14 by IHC.

CONCLUSIONS

We have developed a reliable multicolour FCM assay to detect c-MYC expression suitable for clinical laboratories that should be helpful to accurately quantify c-MYC expression in B-cell lymphomas.

Prognostication of diffuse large B-cell lymphoma in the molecular era: moving beyond the IPI

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with variable outcomes. Despite the majority of patients being cured with combination chemoimmunotherapy, up to 30% eventually succumb to the disease. Until recently, baseline prognostic assessment has centred on the International Prognostic Index (IPI), although this index is yet to impact strongly on treatment choice. Molecular features such as cell of origin, MYC and BCL-2 genetic alterations and protein overexpression were identified over a decade ago, yet their prognostic value is still not fully elucidated. Adding complexity are the plethora of new clinical, biological and molecular prognostic markers described in the recent literature, most of which lack independent validation, likely act as surrogate markers for those already in common use and have yet to substantially impact on therapeutic decision making. This review comprehensively assesses the value of individual prognostic markers in the clinical setting and their potential to predict response to novel agents, and ways to optimise their use in future research.

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.

Concordant bone marrow involvement of diffuse large B-cell lymphoma represents a distinct clinical and biological entity in the era of immunotherapy

In diffuse large B-cell lymphoma (DLBCL), the clinical and biological significance of concordant and discordant bone marrow (BM) involvement have not been well investigated. We evaluated 712 de novo DLBCL patients with front-line rituximab-containing treatment, including 263 patients with positive and 449 with negative BM status. Compared with negative BM disease, concordant BM adversely impacted overall and progression-free survival, independent of the International Prognostic Index (IPI) and cell-of-origin classification. Once BM is concordantly involved, poor prognosis was not associated with the extent of BM involvement. Conversely, patients with discordant BM showed favorable overall survival similar to stage I-II DLBCL. A BM-adjusted IPI, using three parameters: concordant BM involvement, age >60 years, and performance status >1, improves the risk stratification for DLBCL with positive BM. Intensive immunochemotherapy seemingly rendered survival benefit for patients with concordant BM, as did rituximab maintenance for the discordant BM group. Frequently revealing adverse clinical and molecular characteristics, patients with concordant BM demonstrated gene expression signatures relevant to tumor cell proliferation, migration and immune escape. In conclusion, clinical and biological heterogeneity is seen in DLBCL with positive BM but concordant BM involvement represents a distinct subset with unfavorable gene signatures, high-risk clinicopathologic features and poor prognosis.

Clinical Significance of TIPE2 Protein Upregulation in Non-Hodgkin's Lymphoma

Non-Hodgkin's lymphoma (NHL), which includes diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma, is a refractory malignant tumor originated from the lymphatic system. TNFAIP8L2 (TIPE2 or tumor necrosis-alpha-induced protein-8 like 2) is a negative regulator for inflammation and an inhibitor for carcinogenesis. However, whether TIPE2 plays a role in lymphomagenesis is unknown. In this study, we determined TIPE2 expression in NHL by immunohistochemistry and investigated its clinicopathological significance in DLBCL. We found that TIPE2 expression was upregulated in both DLBCL and peripheral T-cell lymphoma. But the expression of TIPE2 in T lymphomas was weaker than that in DLBCL. Interestingly, among DLBCL, TIPE2 expression was significantly stronger in the germinal center B-cell (GCB) type than in the non-GCB type. These results suggest that the expression of TIPE2 protein could be a predictor of better prognosis for DLBCL.

The significance of FOXP1 in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of mature B-cell lymphoma. While the majority of patients are cured with immunochemotherapy incorporating the anti-CD20 monoclonal antibody rituximab (R-CHOP), relapsed and refractory patients still have a dismal prognosis. DLBCL subtypes including an aggressive activated B-cell-like (ABC) and a more favorable prognosis germinal center-like (GCB) DLBCL have been identified by gene expression profiling and are characterized by distinct genetic abnormalities and oncogenic pathways. This identification of novel molecular targets is now enabling clinical trials to evaluate more effective personalized approaches to DLBCL therapy. The forkhead transcription factor FOXP1 is highly expressed in the ABC-DLBCL gene signature and has been extensively studied within the context of DLBCL for more than a decade. Here, we review the significance of FOXP1 in the pathogenesis of DLBCL, summarizing data supporting its utility as a prognostic and subtyping marker, its targeting by genetic aberrations, the importance of specific isoforms, and emerging data demonstrating a functional role in lymphoma biology. FOXP1 is one of the critical transcription factors whose deregulated expression makes important contributions to DLBCL pathogenesis. Thus, FOXP1 warrants further study as a potential theranostic in ABC-DLBCL.

BCL2 and MYC are expressed at high levels in canine diffuse large B-cell lymphoma but are not predictive for outcome in dogs treated with CHOP chemotherapy

Diffuse large B-cell lymphoma (DLBCL) is the most common haematopoietic malignancy in dogs. Recently, MYC and BCL2 expression levels determined with immunohistochemistry (IHC) were found to be prognostic in people with DLBCL. We hypothesized that canine DLBCL can be similarly subdivided into prognostic subtypes based on expression of MYC and BCL2. Cases of canine DLBCL treated with CHOP chemotherapy were retrospectively collected and 43 dogs had available histologic tissue and complete clinical follow-up. Median values of percent immunoreactive versus immunonegative cells were used to determine positive or negative expression status. Completion of CHOP was significantly associated with a positive outcome. Compared with human patients, our canine DLBCL patients had high IHC expression of both MYC and BCL2, and relative expression levels of one or both markers were not associated with clinical outcome.

Prediction of Central Nervous System Relapse of Diffuse Large B-Cell Lymphoma Using Pretherapeutic [18F]2-Fluoro-2-Deoxyglucose (FDG) Positron Emission Tomography/Computed Tomography

Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is a rare complication, but has a poor prognosis with unknown pathophysiology. Recent trials of CNS prophylaxis have shown to be ineffective, despite patient's selection using several known clinical risk factors. In this study, the authors evaluated the value of pretreatment [F]2-Fluoro-2-deoxyglucose positron emission tomography in predicting CNS relapse in DLBCL patients.The authors analyzed 180 pathologically confirmed DLBCL patients, retrospectively. Patients underwent [F]2-Fluoro-2-deoxyglucose positron emission tomography/computed tomography before first line rituximab to cyclophosphamide, doxorubicin, vincristine, and prednisone therapy. Clinical characteristics were evaluated and total lesion glycolysis (TLG) with a threshold margin of 50% was calculated.Among age, sex, Ann Arbor stage, International Prognostic Index, revised International Prognostic Index, high serum lactate dehydrogenase level, presence of B symptoms, bulky disease (≥10 cm), extranodal lesion involvement, bone marrow involvement, high metabolic tumor volume ( >450 mL), and high TLG50 (>2000), the high TLG50 was the only significant prognostic factor for predicting CNS relapse in a multivariate analysis (P = 0.04). Kaplan-Meir survival analysis between high TLG50 (>2000) and low TLG50 (≤2000) groups revealed significantly different mean progression free survival (PFS) of 1317.2 ± 134.3 days and 1968.6 ± 18.3 days, respectively (P < 0.001).High TLG50 on [F]2-Fluoro-2-deoxyglucose positron emission tomography/computed tomography is the most significant predictor of CNS relapse in un-treated DLBCL patients.

Epstein-Barr Virus-Positive Diffuse Large B-Cell Lymphoma in the Elderly: A Matched Case-Control Analysis

Background

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) in the elderly has rarely been reported. This study aimed to explore the clinical characteristics and prognosis of this entity.

Methods

In situ hybridization (ISH) analysis of Epstein-Barr virus (EBV) and immunohistochemistry was performed in 230 tumor specimens from consecutive de novo DLBCL patients over 50 years old. A matched-case control analysis (1:3) was utilized to compare EBV-positive and EBV-negative DLBCL in the elderly.

Results

A total of 16 patients (7.0%) were diagnosed with EBV-positive DLBCL. Of these 16 cases, the median age was 62 years, with a male to female ratio of 11:5. Elderly EBV-positive DLBCL patients had a higher incidence of non-germinal center B-cell (non-GCB) subtypes (87.5%) and high Ki67 (75%) and CD30 expression (93.8%). For EBV-positive patients undergoing initial chemotherapy, 7 of 16 (43.8%) had complete remission, 2 (12.5%) had partial remission, 2 (12.5%) had stable disease, and 5 (31.3%) had progressive disease. The median overall survival was 9 months for the EBV-positive patients. A matched-case control analysis suggested that EBV-positive patients had inferior survival outcomes compared with EBV-negative patients (3-year progression-free survival [PFS]: 25% vs. 76.7%, respectively; 3-year overall survival [OS]: 25% vs. 77.4%, respectively; P<0.001).

Conclusion

EBV-positive DLBCL of the elderly is associated with an inferior clinical course and inferior survival outcomes. The role of EBV in this disease and the optimal management of this subgroup warrants further investigation.

Distribution of Ki67 proliferative indices among WHO subtypes of non-Hodgkin's lymphoma: association with other clinical parameters

BACKGROUND

Non-hodgkin lymphoma (NHL) is a diverse group of disease encompassing divergent tumor types with contrasting clinical behaviors. We aimed to evaluate the usefulness of Ki67 index in segregating indolent from aggressive NHL and its association with clinical parameters.

MATERIALS AND METHODS

During a study period of 4.5 years, a total of 215 cases of lymphomas were diagnosed among of which 172 cases were NHL. Ki67 immunohistochemical staining was performed by the DAKO envision method. Average proportion of tumor cells stained was calculated to determine the proliferative index.

RESULTS

The mean age at diagnosis was 46.2 years +19.8 (3-81) with a male to female ratio of 1.5:1. Mean Ki67 index for indolent NHL included 23% for small cell, 25% for mantle cell, 28.5% for marginal zone and 34.6% for follicular lymphoma. On the other hand, mean Ki67 index for aggressive lymphomas were 66.4%, 66.9%, 80.3%, 83.3% and 94.4% for diffuse large B cell, T cell (NOS), anaplastic large cell, lymphoblastic and burkitts lymphoma respectively. No significant correlation was found between Ki67 index and other clinical parameters like age and extra nodal involvement.

CONCLUSIONS

Ki67 index is a valuable IHC marker to distinguish indolent from aggressive lymphomas especially in small needle biopsies where exact typing may not be possible.

CD43 expression in diffuse large B-cell lymphoma, not otherwise specified: CD43 is a marker of adverse prognosis

CD43 (leukosialin) is a transmembrane glycoprotein expressed in a variety of hematopoietic cells, including B lymphocytes, and a variety of malignancies including lymphoma, leukemia, and solid tumors. CD43 plays an important role in the development of many diseases, and coexpression of CD43 and CD20 on peripheral B cells is a predictive factor of hematopoietic malignancy. Although CD43 is expressed in approximately 25% of diffuse large B-cell lymphomas (DLBCLs), its prognostic significance remains unclear. To analyze CD43 expression in DLBCL, not otherwise specified (DLBCL, NOS), and assess its prognostic value, we analyzed clinical data from 160 patients with DLBCL, NOS. We observed that CD43 expression was detected in 47 (29.4%) of 160 cases. CD43 expression was positively correlated with old age (>60 years), high serum lactate dehydrogenase level, B symptoms, non-germinal center type, and DLBCL, NOS, mortality. Patients with CD43-positive DLBCL, NOS, had poorer overall survival (P < .001, log-rank test) and event-free survival (P < .001, log-rank test) than CD43-negative patients. Univariate analysis showed that CD43 expression, age, sex, Ann Arbor stage, International Prognostic Index category, and germinal center phenotype were prognostic factors for DLBCL, NOS, patient survival. Multivariate analysis showed that CD43 expression was an independent significant prognostic factor for event-free survival (P < .001) and overall survival (P < .001). Based on these data, we conclude that CD43 expression is a novel adverse prognostic factor for patients with DLBCL, NOS.

MYC protein expression in primary diffuse large B-cell lymphoma of the central nervous system

Primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL) is a rare, aggressive subtype of DLBCL, the biology of which is poorly understood. Recent studies have suggested a prognostic role of MYC protein expression in systemic DLBCL, but little is known about the frequency and significance of MYC protein expression in CNS DLBCL. Hence, we investigated MYC protein expression profiles of CNS DLBCL and assessed the relationship between MYC expression and a variety of histopathologic, immunophenotypic, genetic, and clinical features. Fifty-nine CNS DLBCL diagnosed at our institution over the past 13 years were evaluated. The majority of cases (80%) showed centroblastic morphology, and 12 (20%) displayed a perivascular pattern of infiltration. According to the Hans criteria, 41 (69%) cases had a non-germinal center B-cell and 18 (31%) had a germinal center B-cell cell-of-origin (COO) phenotype. Mean MYC protein expression was 50% (median: 50%, range: 10-80%). Forty-three cases (73%) showed MYC overexpression (≥ 40%), and 35 (60%) showed MYC/BCL2 coexpression. MYC overexpression was seen in the single case harboring MYC translocation and in the cases showing increased copies of MYC (27%); however, no significant difference in mean MYC expression was seen between groups harboring or lacking MYC aberrations. In our series, age was associated with a significantly increased risk of death, and the perivascular pattern of infiltration was associated with a significantly increased risk of disease progression. Neither MYC expression (with or without BCL2 coexpression) nor other variables, including COO subtype were predictive of clinical outcome. Our findings indicate that the proportion of CNS DLBCL overexpressing MYC is higher compared to systemic DLBCL, and MYC overexpression appears to be independent of genetic MYC abnormalities. Thus, MYC expression and other immunophenotypic markers used for prognostication of systemic DLBCL might not apply to CNS DLBCL due to differences in disease biology.

Myc-induced SUMOylation is a therapeutic vulnerability for B-cell lymphoma

Myc oncogenic transcription factors (c-Myc, N-Myc, and L-Myc) coordinate the control of cell growth, division, and metabolism. In cancer, Myc overexpression is often associated with aggressive disease, which is in part due to the destruction of select targets by the ubiquitin-proteasome system (eg, SCF(Skp2)-directed destruction of the Cdk inhibitor p27(Kip1)). We reasoned that Myc would also regulate SUMOylation, a related means of posttranslational modification of proteins, and that this circuit would play essential roles in Myc-dependent tumorigenesis. Here, we report marked increases in the expression of genes that encode regulators and components of the SUMOylation machinery in mouse and human Myc-driven lymphomas, resulting in hyper-SUMOylation in these tumors. Further, inhibition of SUMOylation by genetic means disables Myc-induced proliferation, triggering G2/M cell-cycle arrest, polyploidy, and apoptosis. Using genetically defined cell models and conditional expression systems, this response was shown to be Myc specific. Finally, in vivo loss-of-function and pharmacologic studies demonstrated that inhibition of SUMOylation provokes rapid regression of Myc-driven lymphoma. Thus, targeting SUMOylation represents an attractive therapeutic option for lymphomas with MYC involvement.