Clinical, Immunophenotypic, and Genetic Analysis of Adult Lymphomas With Morphologic Features of Burkitt Lymphoma

Malignant primary female genital system lymphoid

Lymphoma is a malignant tumour of the lymphatic system with an incidence rate of about 6.6 per 100,000 people. Among the many lymphoma types, the most common is non-Hodgkin's lymphoma. Lymphomas are common in the gastrointestinal tract, breast, neck, etc., while those in female genital tracts are rare. In this article, we report four cases of primary female genital system lymphoid malignancies diagnosed and treated at our hospital from 2018 to 2023, with a systematic review.

Incidence of Burkitt lymphoma in the United States during 2000 to 2019

Burkitt lymphoma (BL) is an aggressive B-cell lymphoma that occurs worldwide. A study of BL in the US National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program during 1973 to 2005 (n = 3043) revealed three age-specific incidence peaks of BL and rates that were rising. We studied BL cases diagnosed in SEER 22 during 2000 to 2019 (n = 11 626) to investigate age-specific BL incidence rates and temporal trends. The age-standardized BL incidence rate was 3.96/million person-years, with a 2.85:1 male-to-female ratio. The BL rate among both Hispanic and White individuals was higher than in Black individuals (4.52, 4.12 vs 3.14). Age-specific BL rates showed peaks during pediatric, adult and elderly years in males and pediatric and elderly peaks in females. Based on 4524 BL cases with HIV status (SEER 13), only one peak in adult males (45 years) was observed. Overall age-standardized BL incidence rates rose 1.2%/year (not significant) up to 2009 then fell significantly by 2.4%/year thereafter. Temporal trends in BL rates during 2000 to 2019 varied with age group as pediatric BL rates rose 1.1%/year, while elderly BL rates fell 1.7%/year and adult BL rates rose 3.4%/year until 2007 before falling 3.1%/year thereafter. Overall survival from BL was 64% at 2 years, being highest in pediatric patients and lowest in Black and elderly individuals vs other subgroups. Survival improved by 20% between 2000 and 2019. Our data suggest that BL age-specific incidence rates are multimodal and that overall BL rates rose up to 2009 and then fell, suggesting changes in etiological factors or diagnosis.

Case report: Primary ovarian Burkitt's lymphoma: A puzzling scenario in pediatric population

Burkitt's lymphoma (BL) is defined as a highly invasive B-cell lymphoma, usually characterized by an excellent prognosis, more than 90% of children and adolescents being cured with highly dose-intensive multiagent chemotherapy. Primary ovarian localization without involvement of other organs is a rare manifestation of BL, especially in pediatric population. Symptoms at diagnosis are similar to other ovarian lesions and differential diagnosis may be challenging for clinicians. A 12-year-old girl was referred to our institution for abdominal pain and palpable mass observed by the pediatrician. Diagnostic work-up demonstrated a large mass arising from the right ovary, causing compression on abdominal aorta, inferior vena cava, ureters and bowel, with a second smaller lesion on the left ovary. At surgery, a 15 cm-large, ruptured mass arising from the right ovary was found, associated with a second lesion originating from the left ovary (8 cm) and multiple nodules of the greater omentum. Right salpingo-oophorectomy was performed, incisional biopsies were taken from the left ovary and omental nodules and peritoneal fluid samples were collected for cytology. Pathology revealed a Burkitt lymphoma and the patient underwent chemotherapy according to AIEOP LNH-97 Protocol, group R3 with Rituximab. Preoperative diagnosis of primary ovarian lymphoma is extremely difficult. Surgical exploration is often necessary in patients presenting with acute abdominal or pelvic pain; when the suspicion of primary ovarian lymphoma arises intraoperatively, every effort should be made to minimize invasive procedure in order to enhance post-operative recovery.

Gene fusions in tumourigenesis with particular reference to ovarian cancer

Gene fusion, a genomic event that generates a novel gene from two independent genes, has long been known to be implicated in tumourigenesis and cancer progression. It has thus served as a diagnostic and prognostic biomarker in cancer, as well as an ideal therapeutic target in cancer therapy. Gene fusion can arise from chromosomal rearrangement and alternative splicing of transcripts, resulting in deregulation of proto-oncogenes or creation of an oncogenic novel gene. Largely facilitated by next generation sequencing technologies, a plethora of novel gene fusions have been identified in a variety of cancers, which leaves us the challenge of functionally characterising these candidate gene fusions. In this review, we summarise the molecular mechanisms, the oncogenic consequences and the therapeutic implications of verified gene fusions. We also discuss recent studies on gene fusions in both common and rare subtypes of ovarian tumours and how these findings can be translated to cancer therapies to benefit patients carrying these gene fusions.

Phenotypical Characterization and Clinical Outcome of Canine Burkitt-Like Lymphoma

In dogs, Burkitt-like lymphoma (B-LL) is rare tumor and it is classified as a high-grade B-cell malignancy. The diagnosis is challenging because of the similar histologic appearance with other histotypes, no defined phenotypical criteria and poorly described clinical aspects. The aim of the study was to provide a detailed description of clinical and morphological features, as well as immunophenotypical profile of B-LL in comparison with the human counterpart. Thirteen dogs with histologically proven B-LL, for which a complete staging and follow-up were available, were retrospectively selected. Immunohistochemical expression of CD20, PAX5, CD3, CD10, BCL2, BCL6, MYC, and caspase-3 was evaluated. Histologically, all B-LLs showed a diffuse architecture with medium to large-sized cells, high mitotic rate and diffuse starry sky appearance. B-phenotype of neoplastic cells was confirmed both by flow-cytometry and immunohistochemistry. Conversely, B-LLs were negative for BCL2 and MYC, whereas some cases co-expressed BCL6 and CD10, suggesting a germinal center B-cell origin. Disease stage was advanced in the majority of cases. All dogs received CHOP-based chemotherapy with or without immunotherapy. Despite treatment, prognosis was poor, with a median time to progression and survival of 130 and 228 days, respectively. Nevertheless, ~30% of dogs survived more than 1 year. An increased apoptotic index, a high turnover index and caspase-3 index correlated with shorter survival. In conclusion, canine B-LL shows phenotypical differences with the human counterpart along with features that might help to differentiate this entity from diffuse large B-cell lymphoma.

The "Burkitt-like" immunophenotype and genotype is rarely encountered in diffuse large B cell lymphoma and high-grade B cell lymphoma, NOS

Burkitt lymphoma (BL) is a B cell lymphoma composed of monomorphic medium-sized blastic cells with basophilic cytoplasm and a high proliferation index. BL has a characteristic immunophenotype of CD10 and BCL6 positive and BCL2 negative and harbours MYC gene rearrangements (MYCR) in >90% of the cases. Owing to its highly aggressive nature, intensified chemotherapy regimens are usually administered, requiring an exact diagnosis. Since the diagnosis usually warrants an integration of morphologic, immunophenotypic and genetic findings and because there is a morphologic overlap with the new WHO category of high-grade B cell lymphoma, not otherwise specified (HGBL, NOS) and some cases of diffuse large B cell lymphoma (DLBCL), we wanted to test the distinctiveness of the CD10+, BCL6+, BCL2- and MYCR positive immunopheno-genotype in a large cohort of >1000 DLBCL and HGBL. Only 9/982 DLBCL classified by an expert panel of haematopathologists (0.9%) displayed a single MYCR and were CD10+, BCL6+ and BCL2-. In a similar fashion, only one out of 32 HGBL, NOS (3%) displayed the "Burkitt-like" genetic/immunophenotypic constitution. The samples of non-BL showing the BL-typic immunopheno-genotype, interestingly, harboured higher copy number variations (CNV) by OncoScan analysis (mean 7.3 CNVs/sample; range: 2-13 vs. 2.4; range 0-6) and were also distinct from pleomorphic BL cases regarding their mutational spectrum by NGS analysis. This implies that the characteristic immunophenotype of BL, in concert with a single MYCR, is uncommon in these aggressive lymphomas, and that this constellation favours BL.

PRDM15 is a key regulator of metabolism critical to sustain B-cell lymphomagenesis

PRDM (PRDI-BF1 and RIZ homology domain containing) family members are sequence-specific transcriptional regulators involved in cell identity and fate determination, often dysregulated in cancer. The PRDM15 gene is of particular interest, given its low expression in adult tissues and its overexpression in B-cell lymphomas. Despite its well characterized role in stem cell biology and during early development, the role of PRDM15 in cancer remains obscure. Herein, we demonstrate that while PRDM15 is largely dispensable for mouse adult somatic cell homeostasis in vivo, it plays a critical role in B-cell lymphomagenesis. Mechanistically, PRDM15 regulates a transcriptional program that sustains the activity of the PI3K/AKT/mTOR pathway and glycolysis in B-cell lymphomas. Abrogation of PRDM15 induces a metabolic crisis and selective death of lymphoma cells. Collectively, our data demonstrate that PRDM15 fuels the metabolic requirement of B-cell lymphomas and validate it as an attractive and previously unrecognized target in oncology.

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.

[Ovarian Burkitt lymphoma as the primary manifestation: A case report and literature review]

Ovarian involvement as the initial manifestation of a Burkitt lymphoma without detectable extra-ovarian disease is rare, which is why it is usually not included in the differential diagnosis when an ovarian tumor is detected. A missed diagnosis will lead to the wrong treatment being given, and this can compromise any future reproductive wishes of the patient. In this article, a patient presents a Burkitt lymphoma with ovarian involvement as an initial manifestation and an unusually rapid systemic progression of the disease. Prompted by this case and its unusual course, we reviewed the existing literature.

Primary ovarian Burkitt's lymphoma: a rare oncological problem in gynaecology: a review of literature

Purpose

This review presents the information about epidemiology, clinical manifestation, diagnosis and treatment of primary ovarian Burkitt’s lymphoma (BL), including a literature search of available BL cases. The purpose of this review is to draw clinicians’ attention to the possibility of ovarian BL occurrence, which may be important in the differential diagnosis of ovarian tumours.

Methods

PubMed and Web of Science databases were searched using the keywords ‘‘Burkitt’s’’, ‘‘Lymphoma’’, ‘‘Ovarian’’, ‘‘Primary’’, ‘‘Burkitt’s lymphoma’’. Only cases with histopathologically confirmed diagnosis of primary ovarian BL were included in this review.

Results

Fifty articles, reporting cases with an ovarian manifestation of primary non-Hodgkin’s lymphoma, were found. Twenty-one cases with a histopathologically confirmed BL were evaluated to compare various manifestations, treatment and prognosis in ovarian BL.

Conclusions

Primary ovarian BL is a rare condition, included in the entity of non-Hodgkin lymphoma. The tumour can occur uni- or bilaterally in the ovaries with major symptoms such as abdominal pain or a large abdominal mass. Differential diagnosis, based on imaging features and pathological examination of the specimens, is essential for further treatment due to various aetiology of ovarian tumours. Although most of the patients suffering from ovarian BL underwent surgery after the ovarian tumour had been detected, surgical treatment is not the treatment of choice in patients with ovarian lymphoma. The mainstay of therapy is chemotherapy without further surgery. The prognosis is better if the chemotherapy protocol is more aggressive and followed by prophylactic central nervous system chemotherapy. Nowadays, multiagent protocols are administered, which improves the survival rate.

Diagnostic Algorithm of Common Mature B-Cell Lymphomas by Immunohistochemistry

CONTEXT

- Different types of mature B-cell lymphomas, including plasma cell neoplasms, exhibit distinct immunohistochemical profiles, which enable them to be correctly diagnosed. However, except for rare examples of lymphoma-specific immunohistochemistry, such as cyclin D1 in mantle cell lymphoma and annexin A1 in hairy cell leukemia, immunohistochemical profiles of mature B-cell lymphomas overlap and lack specificity.

OBJECTIVES

- To systemically review immunohistochemical features associated with commonly encountered mature B-cell lymphomas based on the presence or absence of CD5 and CD10; to review the immunophenotypic profile of plasma cells derived from plasma cell myelomas and B-cell lymphomas; and to review a group of rare, aggressive B-cell lymphomas with antigen expression features of plasma cells.

DATA SOURCES

- Published and PubMed-indexed English literature was reviewed.

CONCLUSIONS

- Although the presence or absence of CD5 and CD10 expression should be included in the initial immunohistochemistry screening panel for mature B-cell lymphomas, appropriate and judicial use of other B-cell antigens is necessary to ensure correct diagnoses. Furthermore, although the status of CD5 and CD10 expression is associated with certain prototypes of B-cell lymphomas, their expression is not specific. Plasma cells from plasma cell neoplasias and B-cell lymphomas exhibit overlapping but relatively distinct immunophenotypes; thus, a panel of immunohistochemical markers (CD19, CD45, CD56, and CD117) can be employed for their proper identification. Lastly, CD138 staining results are almost always positive in a group of aggressive B-cell lymphomas with plasmablastic features, including plasmablastic plasma cell myeloma, plasmablastic lymphoma, and ALK-1⁺ large B-cell lymphoma.

The importance of CD39, CD43, CD81, and CD95 expression for differentiating B cell lymphoma by flow cytometry

BACKGROUND

B cell lymphomas' (BCL) current diagnosis is usually based on a combination of morphology, immunophenotype, recurrent cytogenetic aberration and clinical features. However, even with these diagnostic tools, a definitive diagnosis can be difficult to achieve. Therefore, the aim of this study was to assess the profile of CD39, CD43, CD81, and CD95 expressions in diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), and Burkitt lymphoma (BL) cases.

METHODS

To address this issue, we investigated the expression of CD39, CD43, CD81, and CD95 by eight-color flow cytometry in retrospective cases from 2014 to 2016.

RESULTS

The study included 27 adult patients diagnosed with DLBCL, FL, and BL during the study period. Four patients were diagnosed with germinal center B cell-like DLBCL (GCB DLBCL), seven with non-GCB DLBCL, nine with FL, and seven with BL. CD39 seems to be especially relevant to differentiate non-GCB DLBCL from BL and from FL. BL showed stronger expression of CD43 when compared to FL and GCB DLBCL. Moreover, CD43 may help to distinguish non-GCB DLBCL from GCB DLBCL. CD81 expression was much stronger in BL when compared to the other three groups of patients. Lastly, CD95 may also help to distinguish BL from the other subtypes, as BL cells expressed this antigen at low levels.

CONCLUSIONS

In combination, CD39, CD43, CD81, and CD95 expressions appear to be helpful to distinguish CD10⁺ BCL, particularly BL. Phenotypic distinction between FL and GCB DLBCL remains challenging and requires further studies. © 2017 International Clinical Cytometry Society.

Molecular Analysis of Genetic Markers for Non-Hodgkin Lymphomas

Molecular analysis complements the clinical and histopathologic tools used to diagnose and subclassify hematologic malignancies. The presence of clonal antigen-receptor gene rearrangements can help to confirm the diagnosis of a B or T cell lymphoma and can serve as a fingerprint of that neoplasm to be used in identifying concurrent disease at disparate sites or recurrence at future time points. Certain lymphoid malignancies harbor a characteristic chromosomal translocation, a finding that may have significant implications for an individual's prognosis or response to therapy. The polymerase chain reaction (PCR) is typically used to detect antigen-receptor gene rearrangements as well as specific translocations that can be supplemented by fluorescence in situ hybridization (FISH) and karyotype analysis. © 2017 by John Wiley & Sons, Inc.

MYC rearranged B-cell neoplasms: Impact of genetics on classification

A cohort comprising 156 patients with B-cell neoplasms harboring an MYC rearrangement was analyzed with respect to phenotypic presentation, molecular markers (TP53, MYC and ID3) and additional cytogenetic abnormalities (concomitantly occurring BCL2, BCL6 and/or CCND1 rearrangements; double, triple or quadruple hit lymphomas = multiple hit lymphomas). MYC translocations occurred as single hit (only MYC rearranged, 63%) or multiple hit lymphoma (37%) and presented as acute leukemia (AL) (14%), Burkitt lymphoma (30%), chronic lymphocytic leukemia (CLL) (21%) or other mature B-cell neoplasms (35%). Multiple hit lymphomas more frequently showed a complex karyotype compared to single hit lymphomas (62% vs. 28%, p < 0.001). Single hit Burkitt lymphomas presented with specific characteristics, by translocation of MYC to an immunoglobulin locus, predominantly a non-complex karyotype (23% vs. 67%, p = 0.012) and a significantly higher ID3 and TP53 mutation frequency (ID3mut: 49% vs. 0%, p = 0.002; TP53mut: 69% vs. 33%, p = 0.045). Additionally, MYC rearranged CLL presented as outstanding group by often showing a non-complex karyotype (85%), absence of ID3 mutations, a high frequency of SF3B1 mutations, and a frequent involvement of non-immunoglobulin loci as MYC-partner genes (61%). Consequently, genetic characteristics distinguish different subgroups of MYC rearranged B-cell neoplasms and therefore may contribute to a new classification system.

Biomarkers in Hematological Malignancies: A Review of Molecular Testing in Hematopathology

BACKGROUND

Molecular interrogation of genetic information has transformed our understanding of disease and is now routinely integrated into the workup and monitoring of hematological malignancies. In this article, a brief but comprehensive review is presented of state-of-the-art testing in hematological disease.

METHODS

The primary medical literature and standard textbooks in the field were queried and reviewed to assess current practices and trends for molecular testing in hematopathology by disease.

RESULTS

Pertinent materials were summarized under appropriate disease categories.

CONCLUSION

Molecular testing is well entrenched in the diagnostic and therapeutic pathways for hematological malignancies, with rapid growth and insights emerging following the integration of next-generation sequencing into the clinical workflow.

MYC-driven aggressive B-cell lymphomas: biology, entity, differential diagnosis and clinical management

MYC, a potent oncogene located at chromosome locus 8q24.21, was identified initially by its involvement in Burkitt lymphoma with t(8;14)(q24;q32). MYC encodes a helix-loop-helix transcription factor that accentuates many cellular functions including proliferation, growth and apoptosis. MYC alterations also have been identified in other mature B-cell neoplasms and are associated with aggressive clinical behavior. There are several regulatory factors and dysregulated signaling that lead to MYC up-regulation in B-cell lymphomas. One typical example is the failure of physiological repressors such as Bcl6 or BLIMP1 to suppress MYC over-expression. In addition, MYC alterations are often developed concurrently with other genetic alterations that counteract the proapoptotic function of MYC. In this review, we discuss the physiologic function of MYC and the role that MYC likely plays in the pathogenesis of B-cell lymphomas. We also summarize the role MYC plays in the diagnosis, prognostication and various strategies to detect MYC rearrangement and expression.

The role of aberrant proteolysis in lymphomagenesis

PURPOSE OF REVIEW

Deregulated proteolysis is increasingly being implicated in pathogenesis of lymphoma. In this review, we highlight the major cellular processes that are affected by deregulated proteolysis of critical substrates that promote lymphoproliferative disorders.

RECENT FINDINGS

Emerging evidence supports the role of aberrant proteolysis by the ubiquitin proteasome system (UPS) in lymphoproliferative disorders. Several UPS mediators are identified to be altered in lymphomagenesis. However, the precise role of their alteration and comprehensive knowledge of their target substrate critical for lymphomagenesis is far from complete.

SUMMARY

Many E3 ligase and deubiquitinases that contribute to regulated proteolysis of substrates critical for major cellular processes are altered in various lineages of lymphoma. Understanding of the proteolytic regulatory mechanisms of these major cellular pathways may offer novel biomarkers and targets for lymphoma therapy.

BCL6 expression correlates with the t(1;19) translocation in B-lymphoblastic leukemia

OBJECTIVES

Study to date suggests that BCL6 protein expression in B-cell neoplasia predominates in germinal center-derived tumors, but less is known regarding its expression in B-lymphoblastic leukemia. Therefore, we designed a comprehensive study of BCL6 expression in B-lymphoblastic leukemia.

METHODS

BCL6, LMO, and HGAL protein expression in B-lymphoblastic leukemia was investigated using immunohistochemical staining of paraffin-embedded bone marrow specimens. Cryptic TCF3(E2A)-PBX1 rearrangements were investigated using interphase fluorescence in situ hybridization.

RESULTS

Six (12%) of 52 B-lymphoblastic leukemias demonstrated BCL6 protein expression, with B-cell lymphoblastic leukemias containing a t(1;19) translocation demonstrating the strongest staining (three of three). Additional t(1;19) cases beyond the screening study showed similar results. Public microarray expression database mining showed that BCL6 messenger RNA expression levels in B-lymphoblastic leukemia correlated with the protein expression findings. Finally, other markers of B-cell development correlated with BCL6 expression in t(1;19) B-lymphoblastic leukemia cases, with LMO2 and HGAL proteins expressed in six (67%) of nine and eight (89%) of nine cases, respectively.

CONCLUSIONS

BCL6 expression is present in a subset of B-lymphoblastic leukemias, especially in cases containing the 1;19 translocation. Investigation for TCF3(E2A)-PBX1 rearrangements may be useful in BCL6-positive B-lymphoblastic leukemia.

Acquisition of a t(11;14)(q13;q32) in clonal evolution in a follicular lymphoma with a t(14;18)(q32;q21) and t(3;22)(q27;q11.2)

Chromosome translocations involving an immunoglobulin (IG) locus and another gene, either BCL or MYC, are common events in B-cell lymphoma. Occasionally, two IG loci, one with BCL and the other with MYC, are simultaneously involved; such cases are classified as double-hit (DH) lymphomas. These tumors often show intermediate histologic features between those of diffuse large B-cell lymphoma and those of Burkitt lymphoma. Patients with DH lymphoma have a poor prognosis. Rarely, lymphomas in which three IG loci are simultaneously involved with two different BCL genes and MYC have been reported. These cases are classified as triple-hit lymphomas; virtually all these are aggressive tumors with an even worse prognosis. We present here a unique case of follicular lymphoma (FL) with rearranged BCL2, BCL6, and BCL1 (also known as CCND1) genes. Lymphoma cells at first clinical relapse had a complex karyotype that included a t(3;22)(q27;q11) and t(14;18)(q32;q21). About 15 years after initial diagnosis, the lymphoma cells showed clonal cytogenetic evolution and acquired a t(11;14)(q13;q32). This article is the first case report of a low grade B-cell lymphoma that had three lymphoma-associated reciprocal translocations not involving MYC and that had a long indolent clinical course.

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.

The role of EBV in the pathogenesis of Burkitt's Lymphoma: an Italian hospital based survey

The exact worldwide incidence of Burkitt’s lymphoma is not known. There are three distinct clinical variants of Burkitt’s lymphoma, each manifesting differences in epidemiology, clinical presentation, morphology, biology and genetic features: the endemic (African), the sporadic (non-endemic), and the immunodeficiency-associated form. In particular, we reported data regarding Burkitt’s lymphoma incidence in the world and across different European countries. Finally, we described clinic-pathological data of 48 Burkitt’s lymphomas occurred in Italy from 2003 to 2013, in 4 different hospitals, two of which located in east side, and the other ones located in the west-coast. Forty Burkitt’s lymphomas occurs in children (age range 3–12), and 8 were adulthood Burkitt’s lymphomas (age range 18–87). In the pediatric group the Male:Female ratio (M:F) was of 4:1, whereas the group of the adult patients has a M:F of 1:1.67. Immunohistochemical detection of Latent Membrane Protein 1 (LMP1) expression and Epstein-Barr virus Encoded RNA (EBER) In Situ Hybridization (ISH) procedures have been performed. Lymphocyte B monoclonal spread has been demonstrated using a Polymerase Chain Reaction (PCR) based method to amplify Fragment Restriction FR1, FR2 and FR3 immunoglobulin heavy chains DNA fragments. Only 38 cases out of 48 were analyzed for LMP-1 showing various percentage of stained cells in 47.4% of the patients.

Considering ISH for EBER detection results:

1 out 2 (50%) adult analyzed cases was positive, with 50% of stained tumor cells (this patient was a 22 years old female, coming from Napoli);

15 out 24 (62.5%) children analyzed Burkitt’s lymphomas resulted as positive for EBER;

the overall positivity has been observed in 16/26 Burkitt’s lymphomas (61.53%).

Finally, EBV has been detected in children and adult patients, one of them with deregulation of the oncogene c-MYC by chromosomal translocation.

Spinal cord compression by B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma in a patient seropositive for human immunodeficiency virus: a case report

Introduction

Although non-Hodgkin’s lymphoma is one of the most common and frequently fatal of the acquired immune deficiency syndrome-defining illnesses, survival has improved significantly since the introduction of antiretroviral therapy. Patients with spinal cord compression resulting from non-Hodgkin’s lymphoma present with clinically acute or rapidly progressive neurologic deficits. The purpose of this case report is to present a case of a patient seropositive for human immunodeficiency virus with spinal cord compression due to B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma.

Case presentation

A 40-year-old Asian man, who was seropositive for human immunodeficiency virus, presented with progressive neurological deficits. Magnetic resonance images of his thoracic spine showed an epidural mass from T2 to T4, resulting in severe cord compression. Emergent surgical decompression and biopsy were performed, followed by palliative radiation therapy. The pathologic findings showed that the specimen was compatible with B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma. Palliative radiation therapy was performed; however, leptomeningeal seeding and pulmonary embolism led to his death.

Conclusions

When a patient infected with human immunodeficiency virus presents with a rapidly progressive spinal tumor accompanying paraplegia, non-Hodgkin’s lymphoma should be considered, and surgical decompression should be weighed with respect to the patient’s general condition and the subtype/prognosis of the lymphoma.

MYC deregulation in lymphoid tumors: molecular mechanisms, clinical consequences and therapeutic implications

MYC is one of the most frequently deregulated oncogenes in human malignancies. It encodes a leucine zipper transcription factor that modulates a broad spectrum of cellular genes responsible for enhancing cell proliferation, cellular metabolism, growth, angiogenesis, metastasis, genomic instability, stem cell self-renewal and reduced differentiation. MYC functions predominantly as an amplifier of expression of already active genes, potentiating the pre-existing transcriptional program, although it can also repress certain transcriptional targets. In mouse models, MYC induces lymphomas, but requires cooperation with other lesions, including inactivation of the p53 pathway, structural alterations of BCL2 family members, or increased PI3K activity. In human B-cell tumors, MYC rearrangements involving the 8q24 region and immunoglobulin heavy or light genes are a hallmark of Burkitt lymphoma (BL), but can also occur in other lymphoid malignancies, that include diffuse large B-cell lymphoma (DLBCL), B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma (BCLU), plasma cell myeloma (PCM), mantle cell lymphoma (MCL) and plasmablastic lymphoma. For non-BL lymphoid malignancies, MYC fusions represent secondary genetic events and exist in the context of complex karyotypes. Regardless of the mechanism deregulating MYC, lymphomas over-expressing MYC are addicted to this oncogene, highlighting the potential clinical utility of MYC targeting strategies. Several promising approaches for pharmaceutical intervention have been suggested which are now in preclinical or clinical development. Herein, we therefore review the molecular pathogenetic mechanisms associated with MYC deregulation in human B-cell lymphomas and their implications for therapies targeting MYC.

Medical history, lifestyle, family history, and occupational risk factors for sporadic Burkitt lymphoma/leukemia: the Interlymph Non-Hodgkin Lymphoma Subtypes Project

BACKGROUND

The etiologic role of medical history, lifestyle, family history, and occupational risk factors in sporadic Burkitt lymphoma (BL) is unknown, but epidemiologic and clinical evidence suggests that risk factors may vary by age.

METHODS

We investigated risk factors for sporadic BL in 295 cases compared with 21818 controls in a pooled analysis of 18 case-control studies in the International Lymphoma Epidemiology Consortium (InterLymph). Cases were defined to include typical BL or Burkitt-like lymphoma. Odds ratios (ORs) and 95% confidence intervals (CIs) for associations were calculated separately for younger (<50 years) and older (≥ 50 years) BL using multivariate logistic regression.

RESULTS

Cases included 133 younger BL and 159 older BL (age was missing for three cases) and they were evenly split between typical BL (n = 147) and Burkitt-like lymphoma (n = 148). BL in younger participants was inversely associated with a history of allergy (OR = 0.58; 95% CI = 0.32 to 1.05), and positively associated with a history of eczema among individuals without other atopic conditions (OR = 2.54; 95% CI = 1.20 to 5.40), taller height (OR = 2.17; 95% CI = 1.08 to 4.36), and employment as a cleaner (OR = 3.49; 95% CI = 1.13 to 10.7). BL in older participants was associated with a history of hepatitis C virus seropositivity (OR = 4.19; 95% CI = 1.05 to 16.6) based on three exposed cases. Regardless of age, BL was inversely associated with alcohol consumption and positively associated with height.

CONCLUSIONS

Our data suggest that BL in younger and older adults may be etiologically distinct.

Primary Burkitt's lymphoma of the thyroid without Epstein-Barr virus infection: A case report and literature review

Primary thyroid lymphomas are rare, and the majority are B-cell lymphoma. Primary Burkitt's lymphoma (BL) of the thyroid is much less common than the other types of lymphoma. The current study presents the case of an eight-year-old male with a mass in the right lobe of the thyroid, which was detected by B-ultrasound. The patient was diagnosed with BL by immunohistochemistry, fluorescence in situ hybridization analysis of MYC (8q24) and immunoglobulin rearrangement assays. Furthermore, subsequent positron emission tomography-computed tomography scans revealed no abnormal metabolites in the left lobe of the thyroid or in other parts of the body following surgery. The patient underwent alternate R-B-NHL-BFM-90-A and R-B-NHL-BFM-90-B treatment for four cycles each following the thyroidectomy. The patient is well and remains free of disease recurrence following almost four years follow-up. The present study discusses this rare case of primary BL of the thyroid and presents a review of the literature. This case report provides evidence that the immediate diagnosis and treatment of primary Burkitt's lymphoma of the thyroid is likely to improve patient outcome.

The combined expression of VPREB3 and ID3 represents a new helpful tool for the routine diagnosis of mature aggressive B-cell lymphomas

Genomic studies, such as gene expression profiling and next-generation sequencing studies, have provided new insights into the phenotypic characteristics and pathogenesis of mature aggressive B-cell lymphomas. In particular, mutations in the transcription factors ID3 and TCF3, leading to overexpression of B-cell receptor components such as VPREB3, have been shown to be specific for Burkitt lymphoma (BL) and play an important tumourigenic role by mediating the activation of the pro-survival phosphatidylinositol-3-OH kinase pathway. We performed immunohistochemical analysis by applying commercially available anti-VPREB3 antibody to a large cohort of 185 genetically and immunophenotypically characterized mature aggressive B-cell lymphomas and analyzed these results together with recent data on ID3 expression. The combined expression of both VPREB3 and ID3 was associated with a diagnosis of BL with high sensitivity (0.77), high specificity (0.75) and high negative predictive values (0.96), however, with lower positive predictive value (0.30). Double negative cases were absent in the group of BLs but could be found in approximately one third of the remaining cases of mature aggressive B-cell lymphomas. Further, we could not identify a correlation with MYC, BCL2 or BCL6 aberrations with neither VPREB3 nor ID3 expression in each of the diagnostic groups analyzed. Our results, which are in line with recently discovered mutations in next-generation sequencing studies, suggest that the combined immunohistochemical detection of VPREB3 and ID3 is applicable to the routine diagnostic in case of mature aggressive B-cell lymphomas. In particular, it represents a useful and routinely applicable diagnostic tool to exclude BL diagnosis in case of single positive or double negative cases.

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.

Primary Burkitt's lymphoma of endometrium and bilateral ovaries in a 6-year-old female: report of a rare entity and review of the published work

We report a case of a 6-year-old girl with primary Burkitt's lymphoma (BL) of endometrium and bilateral ovaries of 1-month duration. To the best of our knowledge, few cases of childhood primary BL of bilateral ovaries have been reported worldwide. However, extensive search of the published work did not reveal any case of primary BL of endometrium and both ovaries. Although rare, BL is a potentially curable malignancy with good prognosis.

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.

[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.

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.

Pediatric, elderly, and emerging adult-onset peaks in Burkitt's lymphoma incidence diagnosed in four continents, excluding Africa

Burkitt's lymphoma (BL) in the general population and immunosuppressed persons with AIDS in the United States was characterized by three age-specific incidence peaks near 10, 40, and 70 years. We hypothesized that BL from different geographical areas may exhibit pediatric, adult, and elderly age incidence peaks. We investigated this hypothesis using data on 3,403 cases obtained from the International Agency for Research on Cancer (1963-2002). Data from Africa were sparse or incomplete, and thus were excluded. Age-standardized rates (ASRs) and age-specific incidence rates were calculated, supplemented with the calculations performed using age-period-cohort (APC) models. The ASR rose 5.3% (95% confidence interval [CI], 5.0-5.6) per year in males and 4.6% (95% CI, 4.5-4.8) in females. The ASR increased gradually in children, steeply in adults and most rapidly in the elderly both in males and in females. Overall, BL male/female ASR ratio was 2.5, but it declined from 3.1 (95% CI, 3.0-3.3) for pediatric BL to 2.3 (95% CI, 2.2-2.4) for adult BL and 1.5 (95% CI, 1.4-1.6) for elderly BL. Age-specific incidence peaks occurred near 10 and 70 years in all regions and periods. A peak near 40 years of age emerged in the mid-1990s, particularly in men. Findings using APC models confirmed those based on the standard analyses. Our findings, based on the international BL cases, support our hypothesis that BL is multimodal and that BL peaks at different ages may be clues to differences in the etiology and/or biology of BL at those ages.

Aggressive B cell lymphomas of the gastrointestinal tract: clinicopathologic and genetic analysis

Aggressive B cell lymphomas of the gastrointestinal tract include Burkitt lymphoma (BL), diffuse large B cell lymphoma, and B cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL. To investigate the clinical characters of DLBCL/BL of the gastrointestinal (GI) tract, 101 cases of aggressive B cell lymphoma of the GI tract were analyzed by immunohistochemistry and fluorescence in situ hybridization (FISH) using break apart probe for c-MYC gene. For cases with c-MYC rearrangement, additional FISH studies with MYC/IgH fusion probe, BCL2 break apart probe, and BCL6 break apart probe were performed. MYC rearrangement was detected in 23 of 101 cases of aggressive B cell lymphomas (22.5%). The cases with MYC rearrangement were divided into 14 BL, three DLBCL/BL, and six DLBCL. One of the three DLBCL/BL had double translocation for MYC and BCL6 gene. Clinically, DLBCL/BL of the GI tract was more akin to Burkitt lymphoma than it is to GI tract DLBCL with c-MYC rearrangement. The overall prognosis of patients with DLBCL/BL was the worst among aggressive B cell lymphomas. DLBCL/BL is uncommon category of B cell lymphoma in the GI tract with aggressive clinical course despite of intensive chemotherapy.

Burkitt lymphoma and atypical Burkitt or Burkitt-like lymphoma: should these be treated as different diseases?

Burkitt lymphoma (BL) is a mature B-cell non-Hodgkin lymphoma with an aggressive clinical course. Since the advent of short, intensive, multiagent chemoimmunotherapy regimens, it has carried a favorable prognosis. BL has been rather well characterized, whereas the other lymphomas morphologically resembling it are more heterogeneous. The cases classified as atypical BL/Burkitt-like lymphoma by the 2001 World Health Organization (WHO) Classification of Tumors of Hematopoietic and Lymphoid Tissue were thought to represent a continuum between BL and diffuse large B-cell lymphoma (DLBCL). The optimal therapeutic strategy for this provisional entity was not definitively established. However, recent incorporation of molecular genetic data into the 2008 WHO Classification has allowed further refinements with significant therapeutic implications, including the designation of a new provisional entity, "B-cell lymphoma, unclassifiable, with features intermediate between BL and DLBCL." This review presents a comprehensive overview of the previously designated provisional entity of atypical BL/BLL in conjunction with a detailed comparison with BL and DLBCL.

Concurrent development of "Burkitt-like" lymphoma and BCL-2-rearranged low-grade B cell lymphoma sharing the same germinal center origin

B cell lymphoma, unclassifiable, with features intermediate between diffuse large B cell lymphoma and Burkitt lymphoma (BL) is a new entity in WHO classification 2008, and includes Burkitt-like transformation of follicular lymphoma (FL). However, the pathological significance of BCL-2/IgH translocation, which is characteristic in FL, in newly diagnosed cases of this disease is not well understood. We report a patient who developed B cell lymphoma with BL-like morphology on the shoulder, whose bone marrow was involved with FL-like cells. BL-like tumor cells harbored amplified c-MYC genes with BCL-2/IgH translocation, but FL-like cells solely had BCL-2/IgH translocation. The sequence analysis of the IgH gene revealed both of cells originated from the same clone, showing that the aggressive BL-like tumor originated from the FL-like clones simultaneously found in the bone marrow. This case suggests that the IgH/BCL-2 translocation found in newly diagnosed Burkitt-like lymphoma indicates a history of FL-like indolent lymphoma, even if such history is not documented.

Double-hit B-cell lymphomas

In many B-cell lymphomas, chromosomal translocations are biologic and diagnostic hallmarks of disease. An intriguing subset is formed by the so-called double- hit (DH) lymphomas that are defined by a chromosomal breakpoint affecting the MYC/8q24 locus in combination with another recurrent breakpoint, mainly a t(14;18)(q32;q21) involving BCL2. Recently, these lymphomas have received increased attention, which contributed to the introduction of a novel category of lymphomas in the 2008 WHO classification, "B cell lymphoma unclassifiable with features intermediate between DLBCL and BL." In this review we explore the existing literature for the most recurrent types of DH B-cell lymphomas and the involved genes with their functions, as well as their pathology and clinical aspects including therapy and prognosis. The incidence of aggressive B-cell lymphomas other than Burkitt lymphoma with a MYC breakpoint and in particular a double hit is difficult to assess, because screening by methods like FISH has not been applied on large, unselected series, and the published cytogenetic data may be biased to specific categories of lymphomas. DH lymphomas have been classified heterogeneously but mostly as DLBCL, the majority having a germinal center phenotype and expression of BCL2. Patients with DH lymphomas often present with poor prognostic parameters, including elevated LDH, bone marrow and CNS involvement, and a high IPI score. All studies on larger series of patients suggest a poor prognosis, also if treated with RCHOP or high-intensity treatment modalities. Importantly, this poor outcome cannot be accounted for by the mere presence of a MYC/8q24 breakpoint. Likely, the combination of MYC and BCL2 expression and/or a related high genomic complexity are more important. Compared to these DH lymphomas, BCL6(+)/MYC(+) DH lymphomas are far less common, and in fact most of these cases represent BCL2(+)/BCL6(+)/MYC(+) triple-hit lymphomas with involvement of BCL2 as well. CCND1(+)/MYC(+) DH lymphomas with involvement of 11q13 may also be relatively frequent, the great majority being classified as aggressive variants of mantle cell lymphoma. This suggests that activation of MYC might be an important progression pathway in mantle cell lymphoma as well. Based on clinical significance and the fact that no other solid diagnostic tools are available to identify DH lymphomas, it seems advisable to test all diffuse large B-cell and related lymphomas for MYC and other breakpoints.

Diagnosis of Burkitt Lymphoma and Related High-Grade B-Cell Neoplasms

Burkitt lymphoma (BL) is an aggressive B-cell neoplasm with an extremely short doubling time that mainly affects children and young adults. Despite having several characteristic features, none is entirely specific for BL and the differential diagnosis may include diffuse large B-cell lymphoma (DLBCL), B lymphoblastic leukemia/lymphoma, and B-cell lymphoma unclassifiable with features intermediate between DLBCL and BL. We outline a practical approach to establish a diagnosis of BL and distinguish it from other high-grade B-cell malignancies. We pay particular attention to B-cell lymphomas with features intermediate between DLBCL and BL, a new diagnostic category in the 2008 World Health Organization classification system that provides a framework for categorizing challenging cases not meeting diagnostic criteria for either "classic" BL or DLBCL.

The basis and rational use of molecular genetic testing in mature B-cell lymphomas

An increasing number of neoplasms are associated with variably specific genetic abnormalities. This is best exemplified by hematological malignancies, in which there is a growing list of entities that are defined by their genetic lesion(s); this is not (yet) the case in mature B-cell lymphomas. However, enhanced insights into the pathogenesis of this large and diverse group of lymphomas have emerged with the ongoing unraveling of a plethora of fascinating genetic abnormalities. The purpose of this review is to synthesize well-recognized data and nascent discoveries in our understanding of the genetic basis of a spectrum of mature B-cell lymphomas, and how this may be applied to contemporary clinical practice. Despite the explosion of new and exciting knowledge in this arena, with the potential for enhanced diagnostic and prognostic strategies, it is essential to remain cognizant of the limitations (and complexity) of genetic investigations, so that assays can be developed and used both judiciously and rationally.

Treatment of Burkitt lymphoma in children and adults: Lessons from Africa

Modern chemotherapy for childhood Burkitt lymphoma has its origins in Africa, where treatment evolved from one or two doses of single agents, which were curative in some patients, to combinations of non-cross-resistant drugs. Subsequently, in Europe and the United States, high-dose methotrexate, high-dose cytarabine, etoposide, and ifosfamide were found to be active in children with recurrent disease and were incorporated into primary therapy for patients with high-risk disease. These third-generation protocols produce overall cure rates around 90%. Therapy regimens for adults with Burkitt lymphoma have been developed by modifying second-generation pediatric protocols, and few investigators have used the third-generation pediatric regimens that include higher doses of methotrexate and additional agents. The weight of evidence strongly suggests that high-dose therapy with stem cell rescue in first remission cannot substitute for intensive therapy from the outset. Tolerance of intensive regimens by the elderly is a legitimate concern, but it seems appropriate to modify therapy only when necessary in individual patients. The value of rituximab and granulocyte colony-stimulating factor in patients undergoing intensive therapy (particularly the elderly) is worthy of further exploration. Because childhood diffuse large-B-cell leukemia (DLBCL) responds equally well to therapy for Burkitt lymphoma, more intensive therapy and intensive support might also give better results in at least a subset of adults with advanced DLBCL-perhaps defined on the basis of limited molecular profiling, which has provided new information about the categories of aggressive B-cell lymphomas.