Clinical significance of MYC expression and/or "high-grade" morphology in non-Burkitt, diffuse aggressive B-cell lymphomas: a SWOG S9704 correlative study

High-grade B-cell lymphoma, not otherwise specified: a multi-institutional retrospective study

In this multi-institutional retrospective study, we examined the characteristics and outcomes of 160 patients with high-grade B-cell lymphoma, not otherwise specified (HGBL-NOS)-a rare category defined by high-grade morphologic features and lack of MYC rearrangements with BCL2 and/or BCL6 rearrangements ("double hit"). Our results show that HGBL-NOS tumors are heterogeneous: 83% of patients had a germinal center B-cell immunophenotype, 37% a dual-expressor immunophenotype (MYC and BCL2 expression), 28% MYC rearrangement, 13% BCL2 rearrangement, and 11% BCL6 rearrangement. Most patients presented with stage IV disease, a high serum lactate dehydrogenase, and other high-risk clinical factors. Most frequent first-line regimens included dose-adjusted cyclophosphamide, doxorubicin, vincristine, and etoposide, with rituximab and prednisone (DA-EPOCH-R; 43%); rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; 33%); or other intensive chemotherapy programs. We found no significant differences in the rates of complete response (CR), progression-free survival (PFS), or overall survival (OS) between these chemotherapy regimens. CR was attained by 69% of patients. PFS at 2 years was 55.2% and OS was 68.1%. In a multivariable model, the main prognostic factors for PFS and OS were poor performance status, lactate dehydrogenase >3 × upper limit of normal, and a dual-expressor immunophenotype. Age >60 years or presence of MYC rearrangement were not prognostic, but patients with TP53 alterations had a dismal PFS. Presence of MYC rearrangement was not predictive of better PFS in patients treated with DA-EPOCH-R vs R-CHOP. Improvements in the diagnostic criteria and therapeutic approaches beyond dose-intense chemotherapy are needed to overcome the unfavorable prognosis of patients with HGBL-NOS.

High-intensity chemotherapy improved the prognosis of patients with high-grade B-cell lymphoma

Objective

High-grade B-cell lymphoma (HGBL) is highly aggressive and has a poor prognosis.

Methods

The clinical data of 76 patients with High-grade B-cell lymphoma treated in our lymphoma center from July 2016 to April 2020 were analyzed retrospectively. The clinical features, treatment and prognosis of patients with two types of high-grade B-cell lymphoma were compared and analyzed.

Results

Among 76 patients with high-grade B-cell lymphoma, 44 cases (57.9%) were high-grade B-cell lymphoma, accompanied by MYC and Bcl-2 and/or Bcl-6 rearrangement (HGBLR) patients, and 32 cases (42.1%) were HGBL, NOS patients. The bone marrow infiltration, IPI (international prognostic index), Ann Arbor stage (III/IV), extranodal disease are more likely to occur in HGBLR group (P <0.05). Survival analysis of patients showed that overall survival (OS) and progression free survival (PFS) in HGBLR group were significantly shorter than those in HGBL, NOS group (median OS: 21 months vs not reached, P=0. 022; median PFS: 5 months vs 12 months, P = 0. 001). Further analysis demonstrated that, as compared with R-CHOP regimen, patients with HGBL who received high-intensity chemotherapy regimens (DA-EPOCH-R, R-CODOX-M/IVAC and R-Hyper-CVAD) had longer OS (median OS, 16 months vs not reached, P=0. 007) and PFS (median PFS, 5 months vs 11 months, P<0.001). Moreover, mu1tivariate ana1ysis showed that high-intensity chemotherapy regimens were independent risk factors for both PFS (P =0.001, HR: 0.306, 95% CI: 0.153-0.610) and OS (P =0.004, HR: 0.262, 95% CI: 0.105-0.656) in patients with HGBL.

Conclusions

HGBLR patients have worse prognosis than patients with HGBL, NOS. High-intensity chemotherapy may improve the prognosis of patients with HGBL.

Therapeutic Outcomes in High-Grade B-Cell Lymphoma, NOS: Retrospective Analysis

The nomenclature high-grade non-Hodgkin's lymphoma was repurposed in the World Health Organization (WHO) 2016 update as high-grade B cell lymphoma (HGBL). However, among the HGBL entities HGBL, not otherwise specified (NOS) remains a poorly described entity with a lack of literature regarding its treatment and prognosis.

The baseline characteristics, treatment, and outcome of HGBL, NOS cases were analyzed. Thirty HGBL, NOS patients were diagnosed between January 2017 and December 2019. Their median age was 49.3 years, and 30% had advanced IPI. The majority received R-CHOP chemotherapy, while five patients received dose-adjusted R-EPOCH. At a median follow-up of 15 months, nine patients had disease progression or relapse. EFS and OS were 22 months (12.1–31.9 months) and 37 months (29.4–44.0 months) respectively. Only NCCN-IPI ≤ 2 showed significant influence on the outcome. The results were similar to the outcomes previously reported.

This study highlights the importance of NCCN-IPI in ascertaining the prognosis of HGBL, NOS. The literature review suggests that more intensive chemotherapy is ideal for HGBL, NOS. However, prospective trials are needed to prove whether the treatment of HGBL, NOS can be tailored based on NCCN-IPI.

Defining and Treating High-grade B-cell lymphoma, NOS

High-grade B-cell lymphoma, not otherwise specified (HGBL, NOS) is a recently introduced diagnostic category for aggressive B-cell lymphomas. It includes tumors with Burkitt-like or blastoid morphology that do not have double-hit cytogenetics and that cannot be classified as other well-defined lymphoma subtypes. HBCL, NOS are rare and heterogeneous; most have germinal center B-cell phenotype, and up to 45% carry a single-hit MYC rearrangement, but otherwise they have no unifying immunophenotypic or cytogenetic characteristics. Recent analyses utilizing gene expression profiling (GEP) revealed that up to 15% of tumors currently classified as diffuse large B-cell lymphoma display a HGBL-like GEP signature, indicating a potential to significantly expand the HGBL category using more objective molecular criteria. Optimal treatment of HGBL, NOS is poorly defined due to its rarity and inconsistent diagnostic patterns. A minority of patients have early-stage disease which can be managed with standard RCHOP-based approaches with or without radiation. For advanced-stage HGBL, NOS, which often presents with aggressive, disseminated disease, high lactate dehydrogenase, and involvement of extranodal organs (including the central nervous system [CNS]), intensified Burkitt lymphoma-like regimens with CNS prophylaxis may be appropriate. However, many patients diagnosed at age > 60 years are not eligible for intensive immunochemotherapy. An improved, GEP and/or genomic-based pathologic classification that could facilitate HGBL-specific trials is needed to improve outcomes for all patients. In this review, we discuss the current clinicopathologic concept of HGBL, NOS, existing data on its prognosis and treatment, and delineate potential future taxonomy enrichments based on emerging molecular diagnostics.

A dose-dense short-term therapy for human immunodeficiency virus/acquired immunodeficiency syndrome patients with high-risk Burkitt lymphoma or high-grade B-cell lymphoma: safety and efficacy results of the "CARMEN" phase II trial

A few prospective trials in HIV-positive patients with Burkitt lymphoma (BL) or high-grade B-cell lymphoma (HGBL) have been reported. Investigated therapies have shown good efficacy but relevant safety problems, with high rates of interruptions, severe mucositis, septic complications, and fungal infections. Here, we report the results of a multicentre phase II trial addressing a new dose-dense, short-term therapy aimed at maintaining efficacy and improving tolerability. The experimental programme included a 36-day polychemotherapy induction followed by high-dose cytarabine-based consolidation and response-tailored BEAM (carmustine, etoposide, cyatarabine, and melphalan)- conditioned autologous stem cell transplantation (ASCT). This therapy would be considered active if ≥11 complete remissions (CR) after induction (primary endpoint) were recorded among 20 assessable patients. HIV-positive adults (median age 42, range 26-58; 16 males) with untreated BL (n = 16), HGBL (n = 3) or double-hit lymphoma (n = 1) were enrolled. All patients had high-risk features, with meningeal and bone marrow infiltration in five and nine patients respectively. The experimental programme was safe and active in a multicentre setting, with only two episodes of grade 4 non-haematological toxicity (hepatotoxicity and mucositis), and no cases of systemic fungal infections; two patients died of toxicity (bacterial infections). Response after induction (median duration: 47 days; interquartile range 41-54), was complete in 13 patients and partial in five [overall response rate = 90%; 95% confidence interval (CI) = 77-100]. All responders received consolidation, and five required autologous stem cell transplant. At a median follow-up of 55 (41-89) months, 14 patients are relapse-free and 15 are alive, with a five-year progression-free survival and an overall survival of 70% (95% CI = 60-80%) and 75% (95% CI = 66-84) respectively. No patient with cerebrospinal fluid (CSF)/meningeal lymphoma experienced central nervous system recurrence. With respect to previously reported regimens, this programme was delivered in a shorter period, and achieved the main goal of maintaining efficacy and improving tolerability.

Lymphocyte-to-Monocyte Ratio May Serve as a Better Prognostic Indicator Than Tumor-associated Macrophages in DLBCL Treated With Rituximab

There are multiple prognostic indicators for diffuse large B-cell lymphoma (DLBCL) including the international prognostic index (IPI), and gene expression profiling (GEP) to classify the disease into germinal center B-cell and activated B-cell subtypes, the latter harboring inferior prognosis. More recently, tumor-associated macrophages (TAM) and lymphocyte-to-monocyte ratio (LMR) were found to have prognostic implications in DLBCL. However, consensus is yet to be reached in terms of the significance of each. In this study, we evaluated the prognostic value of TAM as assessed by CD163 or CD68 positivity by immunohistochemistry on tissue biopsies and LMR was calculated from peripheral blood differential, with focus on the inclusion of rituximab as a treatment modality. The number of CD68-positive cells in the tumor microenvironment did not exhibit significant prognostic value, whereas higher number of CD163-positive cells was associated with inferior overall survival in patients treated with chemotherapy alone. This effect was no longer evident in patients treated with rituximab containing chemoimmunotherapy. In contrast, the prognostic significance of LMR on survival was more persistent regardless of treatment. There was no association between LMR and the number of CD163-positive cells. Our results suggest that LMR is the more easily and widely available prognostic marker in this era of chemoimmunotherapy. Our finding supports previous literature that the effect of TAM can vary according to treatment. Interaction between rituximab and TAM warrant further scientific investigation for mechanistic insights into targeted therapeutics.

Identification of "Double Hit" Lymphomas Using Updated WHO Criteria: Insights From Routine MYC Immunohistochemistry in 272 Consecutive Cases of Aggressive B-Cell Lymphomas

Aggressive lymphomas with MYC and BCL2 and/or BCL6 translocations ("double hit" lymphomas, DHL) represent a distinct diagnostic category in the updated World Health Organization (WHO) classification. The diagnostic yield of MYC immunohistochemistry (IHC) for the identification of DHL is currently uncertain. MYC IHC was performed in 272 consecutive cases of aggressive B-cell lymphoma, and results correlated with fluorescence in situ hybridization (FISH) for MYC translocations. Among 156 patients with IHC and FISH data, MYC IHC identified MYC translocations with 89% sensitivity, 38% specificity, 92% negative predictive value, and 29% positive predictive value. Three of 15 (20%) of DHL were MYC IHC negative. One case contained a MYC translocation detectable IGH/MYC fusion probes but not MYC break-apart probes. A subset of DHL lack MYC protein expression, and recognition of this subset of cases requires FISH testing. These results provide an appropriate diagnostic algorithm for implementation of 2016 WHO diagnostic criteria.

MYC's Fine Line Between B Cell Development and Malignancy

The transcription factor MYC is transiently expressed during B lymphocyte development, and its correct modulation is essential in defined developmental transitions. Although temporary downregulation of MYC is essential at specific points, basal levels of expression are maintained, and its protein levels are not completely silenced until the B cell becomes fully differentiated into a plasma cell or a memory B cell. MYC has been described as a proto-oncogene that is closely involved in many cancers, including leukemia and lymphoma. Aberrant expression of MYC protein in these hematological malignancies results in an uncontrolled rate of proliferation and, thereby, a blockade of the differentiation process. MYC is not activated by mutations in the coding sequence, and, as reviewed here, its overexpression in leukemia and lymphoma is mainly caused by gene amplification, chromosomal translocations, and aberrant regulation of its transcription. This review provides a thorough overview of the role of MYC in the developmental steps of B cells, and of how it performs its essential function in an oncogenic context, highlighting the importance of appropriate MYC regulation circuitry.

A combination of LMO2 negative and CD38 positive is useful for the diagnosis of Burkitt lymphoma

Background

To evaluate the clinical utility of LIM Domain Only 2 (LMO2) negative and CD38 positive in diagnosis of Burkitt lymphoma (BL).

Methods

LMO2 and CD38 expression determined by immunohistochemistry in 75 BL, 12 High-grade B-cell lymphoma, NOS (HGBL,NOS) and 3 Burkitt-like lymphomas with the 11q aberration.

Results

The sensitivity and specificity of LMO2 negative for detecting BL were 98.67 and 100%, respectively; those of CD38 positive were 98.67 and 66.67%, respectively. The sensitivity and specificity of a combination of both for detecting BL were 97.33 and 100%, respectively. In our study, the combined LMO2 negative and CD38 positive results had a higher area under the curve than either LMO2 negative or CD38 positive alone.

Conclusions

A combination of LMO2 negative and CD38 positive is useful for the diagnosis of Burkitt lymphoma.

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.

Low expression of c-Myc protein predicts poor outcomes in patients with hepatocellular carcinoma after resection

Background

Embryonic Liver Fodrin (ELF) is an adaptor protein of transforming growth factor (TGF-β) signaling cascade. Disruption of ELF results in mislocalization of Smad3 and Smad4, leading to compromised TGF-β signaling. c-Myc is an important oncogenic transcription factor, and the disruption of TGF-β signaling promotes c-Myc-induced hepatocellular carcinoma (HCC) carcinogenesis. However, the prognostic significance of c-Myc in HCC is less understood

Methods

The expression of c-Myc protein and mRNA were measured by immunohistochemistry (IHC) and qRT- PCR, respectively. IHC was performed to detect TGF-β1 and ELF expression in HCC tissues. Their relationship with clinicopathological factors and overall survival (OS) and disease free survival (DFS) were examined.

Results

The expression of c-Myc protein and mRNA in HCC tissues were significantly higher in HCC area than those in normal liver tissues. However, the expression were low compared with those adjacent to HCC area. c-Myc protein was independently predictive of DFS and OS, and it was negatively correlated with tumor size (P = 0.031), tumor number (P = 0.038), and recurrence (P = 0.001). Low c-Myc expression was associated with short-term recurrence and poor prognosis. The predictive value of c-Myc combined with TGF-β1 or/and ELF was higher than that of any other single marker. Low c-Myc, high TGF-β1 or/and low ELF expression was associated with the worst DFS and OS.

Conclusions

Low expression of c-Myc protein predicts poor outcomes in patients with HCC with hepatectomy. The combination of the expression of c-Myc, TGF-β1, and ELF can be used to accurately predict outcomes of patients with HCC.

How I treat double-hit lymphoma

These lymphomas, which occur in <10% of cases of diffuse large B-cell lymphoma, have been referred to as double-hit lymphomas (or triple-hit lymphomas if all 3 rearrangements are present). It is important to differentiate these lymphomas from the larger group of double-expressor lymphomas, which have increased expression of MYC and BCL-2 and/or BCL-6 by immunohistochemistry, by using variable cutoff percentages to define positivity. Patients with double-hit lymphomas have a poor prognosis when treated with standard chemoimmunotherapy and have increased risk of central nervous system involvement and progression. Double-hit lymphomas may arise as a consequence of the transformation of the underlying indolent lymphoma. There are no published prospective trials in double-hit lymphoma, however retrospective studies strongly suggest that aggressive induction regimens may confer a superior outcome. In this article, I review my approach to the evaluation and treatment of double-hit lymphoma, with an eye toward future clinical trials incorporating rational targeted agents into the therapeutic armamentarium.

PD1 and PDL1 expression in primary central nervous system diffuse large B-cell lymphoma are frequent and expression of PD1 predicts poor survival

Primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) is a rare and aggressive type of diffuse large B-cell lymphoma (DLBCL) whit poorly understood pathogenesis. Finding biomarkers associated with patient survival may be important for understanding its physiopathology and to develop new therapeutic approaches. We investigated 32 PCNS-DLBCL from immunocompetent patients for BCL2, CMYC, LMO2, and P53 expression and for cytogenetic aberrations of BCL2, BCL6, and MYC genes, all known for their prognostic value in systemic DLBCL (s-DLBCL). We analyzed PD1 and PDL1 protein expression in both tumor infiltrating lymphocytes (TILs) and tumor cells. Finally, we searched for correlation between biological data and clinical course. The PCNS-DLBCL expressed BCL2, CMYC, LMO2, and P53 at similar frequency than s-DLBCL but without significant prognostic on survival. None cases harbored aberrations involving BCL2 and MYC gene whereas BCL6 abnormalities were present in 20.7% of cases but without value on survival. Expression of PD1 in TILs and PDL1 in tumor cells was observed at higher rates than in s-DLBCL (58% and 37%, respectively). The PD1 expression in TILs correlated with PDL1 expression in tumor cells (P = .001). Presence of PD1 positive TILs was associated with poorer overall survival (P = .011). Patients with PDL1 overexpression tended to better response to chemotherapy (P = .23). In conclusion PCNS-DLBCL pathogenesis differs from s-DLBCL without prognostic value of the phenotypic and cytogenetic parameters known for their pejorative impact in the latter. The PD1/PDL1 pathway plays a strong role in PCNS-DLBCL and represents an attractive target for this aggressive lymphoma.

Approach to the diagnosis and treatment of high-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements

High-grade B-cell lymphomas (HGBLs) with MYC and BCL2 and/or BCL6 rearrangements, so-called "double-hit" lymphomas (HGBL-DH), are aggressive lymphomas that form a separate provisional entity in the 2016 revised World Health Organization Classification of Lymphoid Tumors. Fluorescence in situ hybridization (FISH) will be required to identify HGBL-DH and will reclassify a subset of diffuse large B-cell lymphomas (DLBCLs) and HGBLs with features intermediate between DLBCL and Burkitt lymphoma into this new category. Identifying patients with HGBL-DH is important because it may change clinical management. This poses a challenge for centers that may not be ready to handle the additional workload and financial burden associated with the increase in requests for FISH testing. Herein, we review the mechanisms of deregulation of these oncogenes. We identify the factors associated with a poor prognosis and those that can guide diagnostic testing. Restricting FISH analysis to the 10% of DLBCL patients who have a germinal center B-cell phenotype and coexpress MYC and BCL2 proteins would be cost-effective and would identify the subset of patients who are at highest risk of experiencing a relapse following conventional therapy. These patients may benefit from intensified chemotherapy regimens or, ideally, should enroll in clinical trials investigating novel regimens.

Recent Advances in Aggressive Large B-cell Lymphomas: A Comprehensive Review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with considerable heterogeneity reflected in the 2008 World Health Organization classification. In recent years, genome-wide assessment of genetic and epigenetic alterations has shed light upon distinct molecular subsets linked to dysregulation of specific genes or pathways. Besides fostering our knowledge regarding the molecular complexity of DLBCL types, these studies have unraveled previously unappreciated genetic lesions, which may be exploited for prognostic and therapeutic purposes. Following the last World Health Organization classification, we have witnessed the emergence of new variants of specific DLBCL entities, such as CD30 DLBCL, human immunodeficiency virus-related and age-related variants of plasmablastic lymphoma, and EBV DLBCL arising in young patients. In this review, we will present an update on the clinical, pathologic, and molecular features of DLBCL incorporating recently gained information with respect to their pathobiology and prognosis. We will emphasize the distinctive features of newly described or emerging variants and highlight advances in our understanding of entities presenting a diagnostic challenge, such as T-cell/histiocyte-rich large B-cell lmphoma and unclassifiable large B-cell lymphomas. Furthermore, we will discuss recent advances in the genomic characterization of DLBCL, as they may relate to prognostication and tailored therapeutic intervention. The information presented in this review derives from English language publications appearing in PubMed throughout December 2015. For a complete outline of this paper, please visit: http://links.lww.com/PAP/A12.

Outcomes of MYC-associated lymphomas after R-CHOP with and without consolidative autologous stem cell transplant: subset analysis of randomized trial intergroup SWOG S9704

Double hit lymphoma (DHL) and double protein-expressing (MYC, BCL2) lymphomas (DPL) fare poorly with R-CHOP (rituximab + cyclophosphamide, doxorubicin, vincristine, prednisolone); consolidative autologous stem cell transplant (ASCT) may improve outcomes. S9704, a phase III randomized study of CHOP +/-R with or without ASCT enabled evaluation of intensive consolidation. Immunohistochemistry (IHC) identified 27 of 198 patients (13·6%) with MYC overexpression; 20 (74%) harboured concurrent BCL2 overexpression. Four had DHL and 16 had DPL only. With median 127 months follow-up, there is a trend favouring outcomes after ASCT in DPL and MYC protein overexpressing patients, whereas all DHL patients have died irrespective of ASCT.

Comprehensive Assessment and Classification of High-Grade B-cell Lymphomas

High-grade B-cell lymphomas (HGBCLs) are a heterogeneous group of neoplasms that include subsets of diffuse large B-cell lymphoma, Burkitt lymphoma, and lymphomas with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma. Morphologically indistinguishable HGBCLs may demonstrate variable clinical courses and responses to therapy. The morphologic evaluation and classification of these neoplasms must be followed by further genetic and immunophenotypic work-up. These additional diagnostic modalities lead to a comprehensive stratification of HGBCL that determines the prognosis and optimal therapy. This article reviews the well-established and emerging biomarkers that are most relevant to the clinical management of HGBCL.

MYC Immunohistochemistry to Identify MYC-Driven B-Cell Lymphomas in Clinical Practice

OBJECTIVES

Immunohistochemistry with anti-MYC antibody (MYC IHC) detects MYC protein in fixed samples of aggressive B-cell lymphomas and, according to the number of positive staining tumor nuclei, facilitates tumor subclassification, predicts underlying MYC rearrangements, and stratifies patient outcome. We aimed to determine the performance of MYC IHC in clinical practice.

METHODS

We reviewed MYC IHC performed on control specimens and 256 aggressive B-cell lymphomas and compared clinically reported IHC scores with experts' review.

RESULTS

Control tissues showed less than 5% variation in daily IHC staining. Reported and expert IHC scores were well correlated (r = 0.86) with an SD of 14.2%. Reported IHC scores 30% or less and 70% or more were accurate (94.5%) compared with experts in categorizing tumors as "MYC IHC-Low" and "MYC IHC-High," respectively, but scores 40% to 60% were not (60.3%). The mean IHC score among lymphomas with MYC rearrangements was 80%, but with a large range of scores (20%-100%). There was no statistically significant association between IHC score and MYC copy number.

CONCLUSIONS

Under optimal conditions, clinically reported MYC IHC scores are concordant with expert scores within 15%. MYC IHC does not capture all B-cell lymphomas with MYC rearrangements, however. MYC IHC and MYC fluorescence in situ hybridization are both recommended to identify MYC-driven B-cell lymphomas.

Using the pathology report in initial treatment decisions for diffuse large B-cell lymphoma: time for a precision medicine approach

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non Hodgkin lymphoma in the Western world, and is potentially curable with standard R-CHOP chemoimmunotherapy. Historically, clinical risk assessments provided prognostic information, but did not define treatment approach. We are now in an era where the heterogeneity of DLBCL is defined genetically and molecularly, and rational subset-specific therapeutic targets are guiding clinical trials. Primary mediastinal DLBCL is a unique clinicopathologic entity, and alternatives to R-CHOP may confer superior outcome. Rearrangement of the myc oncogene occurs in ∼10% of patients with DLBCL, and confers a very poor prognosis with standard R-CHOP, particularly when there is concomitant rearrangement of bcl-2, a condition referred to as “double-hit” DLBCL. A larger subset of DLBCL demonstrates overexpression of both myc and bcl-2 by immunohistochemistry. Cell of origin, determined by gene expression analysis, immunohistochemistry algorithms, or a novel Lymph2Cx platform, provides prognostic information, and guides therapeutic decisions in both relapsed and de novo disease. This article will define specific subsets of DLBCL and provide subtype-specific treatment options, including novel approaches under investigation. Understanding these key features of the pathology report, and limitations of these assays defining subsets of DLBCL, allows for an evolving precision medicine approach to this disease.

Update in large cell lymphoma: understanding the pathology report

The diffuse aggressive large B-cell lymphomas are a heterogeneous group of B-cell malignancies. Although many are readily recognized due to characteristic clinical and pathologic features, several problematic areas still exist in diagnosis of these lymphomas due to a variety of reasons that include imprecise or difficult-to-apply diagnostic criteria, gaps in our understanding of lymphoma biology, and limitations in technologies available in the clinical laboratory compared to the research laboratory. This may result in some degree of confusion in the pathology report, particularly if the issues are not clearly explained, leading to frustration or misinterpretation on the part of the reader. In this review, I will discuss the pathologic features of a subset of the WHO 2008 classification diffuse aggressive large B-cell lymphomas, focusing on areas in which difficulties exist in diagnosis and/or biomarker marker assessment. A deeper understanding of the issues and areas of uncertainty due to limitations in our knowledge about the biology of these diseases should lead to better communication between pathologists and clinicians.

An analysis of MYC and EBV in diffuse large B-cell lymphomas associated with angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma not otherwise specified

Composite diffuse large B-cell lymphomas (DLBCLs) with peripheral T-cell lymphomas (PTCLs) are rare co-occurrences with poorly understood pathologic features. Herein, we describe 15 distinct cases of DLBCL occurring in association with PTCL, including angioimmunoblastic T-cell lymphoma (AITL; n = 12) and PTCL, not otherwise specified (n = 3). Sheets of large B cells were seen in all cases, with Hodgkin/Reed-Sternberg-like (HRS-L) cells present in 6 cases. When compared to cases of AITL without DLBCL, HRS-L cells were more frequently seen in cases of AITL with DLBCL (P = .02). Epstein-Barr virus (EBV) expression was seen in 10 of 15 cases, and in those with HRS-L cells, EBV expression was detected invariably in at least a subset of the HRS-L cells. MYC gene rearrangements were consistently absent, although 6 of the 10 cases showed MYC overexpression by immunohistochemistry in the neoplastic B cells; a frequency significantly increased compared to other cases of DLBCL not associated with a T-cell lymphoma: 29 of 166 (P = .005). In addition, when MYC was overexpressed in DLBCL, it was also weakly present in the HRS-L cells. The increased and frequent morphologic presence of HRS-L cells in association with this composite lymphoma raises a possible link between their occurrence and DLBCLs in PTCLs; furthermore, the frequent detection of MYC protein expression and EBV infection in these cases suggests a possible role of these pathways in B-cell lymphomagenesis.

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.

Aggressive B-cell lymphomas: a review and practical approach for the practicing pathologist

Recent advances in diffuse large B-cell lymphoma are changing the way pathologists approach, diagnose, and report on this heterogeneous group of lymphomas. The purpose of this review is to provide a practical yet comprehensive approach to diffuse large B-cell lymphoma and aggressive B-cell lymphomas that can be used and easily interpreted by pathologists at all levels of training. It will address important concepts and current testing modalities which provide important prognostic information for the clinician when considering appropriate chemotherapeutic regimens for each patient's lymphoma diagnosis. It will also provide some insights into recently reported signaling pathways and molecular alterations and their contribution to lymphomagenesis and how identifying these abnormalities may provide future potential therapeutic targets for these aggressive lymphomas.

Practical Applications in Immunohistochemistry: Evaluation of Diffuse Large B-Cell Lymphoma and Related Large B-Cell Lymphomas

Context

Diffuse large B-cell lymphoma is the most commonly diagnosed subtype of lymphoma worldwide. The current World Health Organization (WHO) classification includes several subtypes, based on a combination of clinical, immunohistochemical, and genetic differences. Immunohistochemical staining is essential in evaluating diffuse large B-cell lymphoma and many related large B-cell lymphomas and aggressive B-cell lymphomas.

Objective

To address different immunohistochemical features used for identification, subclassification, prognosis and in some cases, therapy, of diffuse large B-cell lymphoma and related lymphomas.

Data Sources

The information outlined in this review article is based on our experiences with routine cases, on the current WHO classification of hematopoietic and lymphoid tumors, and on a review of English-language articles published throughout 2014.

Conclusions

Features and diagnostic criteria of diffuse large B-cell lymphoma, aggressive variants of B-cell lymphomas, including Burkitt lymphoma and “double-hit” lymphomas, are discussed. Identification of cell of origin (germinal center type versus activated B-cell type) is discussed at length. Finally, practical approaches for diagnosis are discussed.

Pathology of B-cell lymphomas: diagnosis and biomarker discovery

The diagnosis of B-cell non-Hodgkin lymphomas has changed significantly over the past few decades as new immunophenotypic markers, molecular subtype classification schemes, and novel biomarkers have emerged. Meanwhile, there has been an increasing emphasis on individualizing treatment approaches in accordance with a biologic heterogeneity that has been uncovered within many of the individual B-cell lymphoma entities. The application of high-throughput genomic sequencing to B-cell lymphomas has yielded large amounts of valuable information. The data encompass discoveries essential to an understanding of pathogenesis, clonal or tumoral evolution, and identification of biomarkers that may be useful for prognostic or therapeutic considerations. The following review discusses several of the more common, primarily tissuebased B-cell lymphomas, with a focus on pathologic classification and certain phenotypic characteristics or genetic lesions that apply to refinement of diagnosis and therapy.

What is the role of autologous transplant for lymphoma in the current era?

The role of autologous hematopoietic stem cell transplantation (ASCT) in the management of non-Hodgkin's lymphoma (NHL) is evolving, in the era of novel agents. Multiple histologies and remission stages have been impacted with changing outcomes. In the 1990s, ASCT could cure 50% of relapsed chemosensitive aggressive NHL; now the percentage maybe as low as 20% for patients relapsing within 1 year of completing rituximab-containing induction. Yet recent trials have clarified the value of first remission ASCT for high-grade NHL, the utility of augmented preparative regimens, the efficacy of ASCT in primary CNS lymphoma and in the elderly and analyses have defined strategies to reduce transplant related myeloid malignancies. In addition, optimizing nontransplant induction therapy for mantle cell and double-hit NHL is leading to improved outcomes and a re-examination of the use of ASCT in first complete remission. Caution is needed, however, as delaying transplants may mean that patients will need more morbid allogeneic transplants to achieve long-term control of refractory disease. As an alternative, maintenance therapy trials to improve ASCT outcome in high-risk patients are starting, based on the efficacy of lenolidomide and brentuximab in myeloma and Hodgkin's lymphoma, respectively. In addition, efforts to define early high-risk patients by minimal residual disease (MRD) assessments and genetic profiling, are beginning even for those with "indolent" phenotypes not currently autotransplanted. These efforts should not only refine but also enhance the value of early potentially curative ASCT, especially if novel agents only delay but do not prevent relapse for patients with NHL.

Diagnosis of ‘double hit’ diffuse large B-cell lymphoma and B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma: when and how, FISH versus IHC

Identification of large B-cell lymphomas that are “extra-aggressive” and may require therapy other than that used for diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), is of great interest. Large B-cell lymphomas with MYC plus BCL2 and/or BCL6 rearrangements, so-called ‘double hit’ (DHL) or ‘triple hit’ (THL) lymphomas, are one such group of cases often recognized using cytogenetic FISH studies. Whether features such as morphologic classification, BCL2 expression, or type of MYC translocation partner may mitigate the very adverse prognosis of DHL/THL is controversial. Classification of the DHL/THL is also controversial, with most either dividing them up between the DLBCL, NOS and B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma (BCLU) categories or classifying at least the majority as BCLU. The BCLU category itself has many features that overlap those of DHL/THL. Currently, there is growing interest in the use of MYC and other immunohistochemistry either to help screen for DHL/THL or to identify “double-expressor” (DE) large B-cell lymphomas, defined in most studies as having ≥40% MYC+ and ≥50%-70% BCL2+ cells. DE large B-cell lymphomas are generally aggressive, although not as aggressive as DHL/THL, are more common than DHL/THL, and are more likely to have a nongerminal center phenotype. Whether single MYC rearrangements or MYC expression alone is of clinical importance is controversial. The field of the DHL/THL and DE large B-cell lymphomas is becoming more complex, with many issues left to resolve; however, great interest remains in identifying these cases while more is learned about them.

Molecular classification of MYC-driven B-cell lymphomas by targeted gene expression profiling of fixed biopsy specimens

Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) are aggressive tumors of mature B cells that are distinguished by a combination of histomorphological, phenotypic, and genetic features. A subset of B-cell lymphomas, however, has one or more characteristics that overlap BL and DLBCL, and are categorized as B-cell lymphoma unclassifiable, with features intermediate between BL and DLBCL (BCL-U). Molecular analyses support the concept that there is a biological continuum between BL and DLBCL that includes variable activity of MYC, an oncoprotein once thought to be only associated with BL, but now recognized as a major predictor of survival among patients with DLBCL treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). We tested whether a targeted expression profiling panel could be used to categorize tumors as BL and DLBCL, resolve the molecular heterogeneity of BCL-U, and capture MYC activity using RNA from formalin-fixed, paraffin-embedded biopsy specimens. A diagnostic molecular classifier accurately predicted pathological diagnoses of BL and DLBCL, and provided more objective subclassification for a subset of BCL-U and genetic double-hit lymphomas as molecular BL or DLBCL. A molecular classifier of MYC activity correlated with MYC IHC and stratified patients with primary DLBCL treated with R-CHOP into high- and low-risk groups. These results establish a framework for classifying and stratifying MYC-driven, aggressive, B-cell lymphomas on the basis of quantitative molecular profiling that is applicable to fixed biopsy specimens.