Classification Of B-cell Lymphoma Research Articles

Real-World Impact of Differences in the World Health Organization (WHO) Classification and International Consensus Classification (ICC) Systems on the Diagnosis of Non-Hodgkin Lymphoma: An Analysis from the LEO Cohort Study

Introduction: The use of standardized, evidence-based classification systems is crucial for the accurate diagnosis and treatment of diseases. Moreover, standardized classification facilitates research and epidemiologic studies and promotes consistency in communication among healthcare professionals. Since 2016, the revised 4 th edition of the World Health Organization classification (WHO-HAEM4R) has been the global standard for diagnosis of lymphoid malignancies. With the emergence of new data, 2 new classification systems were developed and published in 2022: the 5 th edition of the WHO Classification (WHO-HAEM5) and the International Consensus Classification (ICC). Both WHO-HAEM5 and ICC maintain a shared fundamental concept of disease classification that integrates clinical, pathologic, and molecular data. However, they differ on nomenclature, establishment of new entities, and/or diagnostic criteria for some disease categories. To evaluate the impact of these differences on real-world diagnosis of non-Hodgkin lymphoma (NHL), we examined the diagnostic classification of NHL in the Lymphoma Epidemiology of Outcomes (LEO) Cohort Study (NCT02736357). Methods: Initiated in 2015, LEO is an ongoing prospective observational study of patients aged ≥18 years with newly diagnosed NHL. Patients are enrolled at 8 major U.S. medical centers. Clinical, epidemiologic, pathologic, and treatment data are abstracted at baseline and active follow-up is conducted for all patients. Lymphoma subtype is coded for each case based on expert hematopathology re-review of the diagnostic pathology slides, the pathology report, biomarker data, and clinical data. Of note, NHL subtype distribution is similar to SEER data. We studied all patients enrolled in LEO between 7/1/2016 (the date LEO pathology review started using WHO-HAEM4R diagnostic codes) and 5/31/2020. WHO-HAEM4R diagnoses and additional clinicopathologic data, when relevant, were used to map cases into the corresponding WHO-HAEM5 and ICC diagnoses. Differences between WHO-HAEM5 and ICC were annotated for each case as: None - same disease entity; Minor - difference in nomenclature with similar diagnostic criteria; Major - difference in disease category and/or diagnostic criteria; or Unevaluable - insufficient data to assign WHO-HAEM5 and/or ICC diagnosis. Results: LEO enrolled 6143 patients during the study period. Of these, comparison between WHO-HAEM5 and ICC was evaluable in 5730 (93.3%). Unevaluable cases included those without a specific WHO-HAEM4R diagnosis at enrollment (N=384; e.g., patients with a low-grade B-cell lymphoma that could not be definitively sub-classified) and those with a specific WHO-HAEM4R diagnosis, but with insufficient clinicopathologic data to assign a specific WHO-HAEM5 and/or ICC diagnosis (N=29). Of the 5730 evaluable cases, 5376 (93.8%) showed no difference between WHO-HAEM5 and/or ICC diagnosis, 311 (5.4%) showed minor differences (nomenclature only), and 43 (0.8%) showed major differences (Table 1). The 43 major differences all involved B-cell NHLs; 20 (46.5%) were attributable to different approaches to classifying double-hit lymphomas, 21 (48.9%) to classification of splenic/leukemic B-cell lymphomas, and 2 (4.6%) to classification of B-cell lymphomas occurring at specific anatomic sites (Table 2). Conclusion: In a large, prospective lymphoma cohort reflecting real-world clinical practice at 8 major U.S. medical centers, major diagnostic differences in the classification of NHL using WHO-HAEM5 or ICC classification criteria were seen in 0.8%, whereas the remaining 99.2% of diagnoses were either the same or showed differences in nomenclature only. The existence of 2 concurrent classification systems presents potential for discrepancies in pathologic diagnosis, clinical practice, clinical trials, and other lymphoma research. Furthermore, some of the differences between WHO-HAEM5 and ICC are clinically and potentially therapeutically significant, and their resolution requires further study. Nevertheless, our findings argue that the proportion of patients affected would be small in real-world practice settings. This appears largely related to incidence rates of specific lymphoma subtypes, with major differences between the 2 classifications predominantly affecting rare entities, while there is general concordance on the most common forms of NHL.

Integration of molecular testing for the personalized management of patients with diffuse large B-cell lymphoma and follicular lymphoma

Diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) are the most common forms of aggressive and indolent lymphoma, respectively. The majority of patients are cured by standard R-CHOP immunochemotherapy, but 30%-40% of DLBCL and 20% of FL patients relapse or are refractory (R/R). DLBCL and FL are phenotypically and genetically hereterogenous B-cell neoplasms. To date, the diagnosis of DLBCL and FL has been based on morphology, immunophenotyping and cytogenetics. However, next-generation sequencing (NGS) is widening our understanding of the genetic basis of the B-cell lymphomas. In this review we will discuss how integrating the NGS-based characterization of somatic gene mutations with diagnostic or prognostic value in DLBCL and FL could help refine B-cell lymphoma classification as part of a multidisciplinary pathology work-up. We will also discuss how molecular testing can identify candidates for clinical trials with targeted therapies and help predict therapeutic outcome to currently available treatments, including chimeric antigen receptor T-cell, as well as explore the application of circulating cell-free DNA, a non-invasive method for patient monitoring. We conclude that molecular analyses can drive improvements in patient outcomes due to an increased understanding of the different pathogenic pathways affected by each DLBCL subtype and indolent FL vs R/R FL.

Classification of B-Cell Lymphomas and Immunodeficiency-Related Lymphoproliferations: What’s New?

New insights from genomic studies have had an impact on the definition and the diagnosis of several lymphoid tumors including follicular B-cell lymphomas, aggressive diffuse large B-cell lymphomas, and lymphoproliferations associated with acquired and posttransplant immunodeficiencies. Follicular lymphoma (FL) includes tumors whose behavior varies widely from indolent/early lesions to aggressive/transformed lymphomas. Although some large B-cell lymphomas can be subclassified as specific entities, the majority lack the characteristics necessary for subclassification and, thus, are termed diffuse large B-cell lymphoma, NOS. There have been, however, some changes in the classification of specific subtypes of large B-cell lymphoma as well as the addition of new entities, a few of which are highlighted in this article. The immunodeficiency-related lymphoproliferative disorders are currently divided into four major categories based on the clinical setting in which they arose: primary immune deficiency, post-transplant, HIV infection, and iatrogenic immunosuppression. In the two upcoming classifications systems for hematolymphoid neoplasms, International Consensus Classification (ICC) and WHO-HAEM-5, there is a divergence in the approach to categorize these lesions. Furthermore, whereas the WHO-HAEM-5 confirms the ability to classify a spectrum of EBV+ lesions as EBV+ DLBCL, NOS, the ICC has separated out lesions that are composed of a heterogenous cellular infiltrate into a new separate category, “EBV-positive polymorphic B cell lymphoproliferative disorder, NOS”. Both WHO-HAEM-5 and ICC recognize a number of KSHV/HHV8-associated lymphoid lesions and acknowledge that there is significant overlap among the different lesions. In the future, translation of these innovations in general practice requires further validation.

Ancillary Studies in the Diagnostic Evaluation of Large B-Cell Lymphoma.

Large B-cell lymphoma classification has changed significantly over the decades, evolving from a purely morphologic categorization to one using sophisticated ancillary studies including molecular analysis, immunohistochemistry, and cytogenetics, in addition to morphology and clinical presentation. To discuss and interpret the key ancillary studies required for subclassification in 2019 and review the differential diagnosis of diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS). Recent literature on the subcategories of large B-cell lymphoma is reviewed, along with relevant updates from the 2016 World Health Organization Classification of Tumours of Hematopoietic and Lymphoid Tissues, with an emphasis on Epstein-Barr virus-positive lymphoproliferative disorders, high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, and large B-cell lymphoma with IRF4 rearrangement. Cases with DLBCL, NOS histology can be further subclassified on the basis of cell of origin studies, Epstein-Barr virus-encoded small RNAs, MYC and BCL2 and/or BCL6 rearrangement studies, and other relevant cytogenetic and immunohistochemical studies. The diagnosis of DLBCL, NOS is therefore a diagnosis of exclusion.

Aggressive B-cell lymphomas—from morphology to molecular pathogenesis

The2016 revised World Health Organization (WHO) classification of lymphoidmalignancies recognizes several distinct entities within the group of diffuselarge B-cell lymphoma (DLBCL) characterized by unique clinical and pathologicalfeatures. Nevertheless, diffuse large B-cell lymphoma, not otherwise specified(DLBCL, NOS) is the most common aggressive B-cell lymphoma. In the last 20 yearsour understanding of the genetic changes and biology of DLBCL has increasedtremendously. According to the 2016 WHO classification, the diagnosis of DLBCL,NOS, should include cell of origin (COO); germinal centre B-cell (GCB) oractivated B-cell (ABC)/non-GCB subtypes, because of their different molecularfeatures, biologic behavior, prognosis and treatment. High-grade B-celllymphoma (HGBL) with MYC and BCL2 and/or BCL6 rearrangements (i.e., double-hit or triple-hit lymphoma, DHL or THL) as well asHGBL, NOS, are two new categories in the 2016 revised WHO classification thatsubstituted the provisional category of B-cell lymphoma, unclassifiable (BCLU)with features intermediate between DLBCL and Burkitt lymphoma (BL), which wasintroduced in the 2008 WHO classification. The pathogenesis and molecularchanges of BL are better understood and led to the recognition of a newprovisional entity called Burkitt-like lymphoma with 11q aberration. In thisarticle, we will review the progress made in the last years within the mostcommonly encountered aggressive B-cell lymphomas, highlighting the betterunderstanding of the underlying disease mechanisms that eventually might be translatedinto more rational and effective therapeutic strategies. Controversial issuesabout fluorescent in situ hybridization (FISH) for the detection of MYC , BCL2 and BCL6 translocations will be addressed, as well as newmolecular techniques used to improve diagnosis and prognostication inaggressive B-cell lymphomas.

KLHL6 Is Preferentially Expressed in Germinal Center-Derived B-Cell Lymphomas.

KLHL6 is a recently described BTB-Kelch protein with selective expression in lymphoid tissues and is most strongly expressed in germinal center B cells. Using gene expression profiling as well as immunohistochemistry with an anti-KLHL6 monoclonal antibody, we have characterized the expression of this molecule in normal and neoplastic tissues. Protein expression was evaluated in 1,058 hematopoietic neoplasms. Consistent with its discovery as a germinal center marker, KLHL6 was positive mainly in B-cell neoplasms of germinal center derivation, including 95% of follicular lymphomas (106/112). B-cell lymphomas of non-germinal center derivation were generally negative (0/33 chronic lymphocytic leukemias/small lymphocytic lymphomas, 3/49 marginal zone lymphomas, and 2/66 mantle cell lymphomas). In addition to other germinal center markers, including BCL6, CD10, HGAL, and LMO2, KLHL6 immunohistochemistry may prove a useful adjunct in the diagnosis and future classification of B-cell lymphomas.

Klasyfikacja WHO 2016 chłoniaków z komórek B — ważne zmiany

W zaktualizowanej klasyfikacji Światowej Organizacji Zdrowia (WHO) 2016 chłoniaków z ko­mórek B uwzględniono najnowsze dane dotyczące objawów klinicznych, biologii, patomorfologii, kryteriów diagnostycznych i bardzo intensywnie rozwijających się badań genetycznych, głównie w zakresie już istniejących jednostek histoklinicznych. Zwrócono szczególną uwagę na wczesne sta­dia limfoidalnej neoplazji, grupę wysoce agresywnych chłoniaków z komórek B oraz na znaczenie nowych badań genetycznych/molekularnych, szczególnie w kontekście potencjalnego zastosowania w terapiach celowanych. Pojawiło się kilka nowych jednostek „tymczasowych”. Podobnie jak w poprzednich wydaniach zaktualizowana klasyfikacja WHO 2016 chłoniaków z komórek B jest platformą do kodyfikacji zmieniających się danych, stanowiąc wyraz porozumienia między hema­topatologami, genetykami i klinicystami w zakresie potencjalnie kontrowersyjnych zagadnień. Jest również podstawą do wytycznych praktycznego postępowania klinicznego.

Characteristics and classification of high-grade B-cell lymphomas in resource-limited settings

Distinguishing Burkitt lymphoma (BL) from diffuse large B-cell lymphoma (DLBCL), important for prognosis and guiding therapy, typically requires a panel of immunohistochemistry (IHC) and FISH. We define a practical approach to high-grade B-cell lym-phoma classification in resource-limited settings. Among 65 cases previously diagnosed as DLBCL from 3 Kenyan hospitals, 43/65 cases (66%) were reclassified as DLBCL, 19 (29%) as BL, and 3 (5%) as plasmablastic lymphoma (PBL) based on a combination of morphology and IHC, with MYC and BCL 2 FISH in select cases. All BL were CD10+ with high MYC (median 80%, range 25–100%) and Ki67 (median 75%, range 0–100%); 18/19 (95%) were BCL2-. Ki67 was higher in BL vs DLBCL ( p = 0.002) and >40% MYC more commoninBL vs DLBCL ( p

Portraying the Expression Landscapes of B-CellLymphoma-Intuitive Detection of Outlier Samples and of Molecular Subtypes.

We present an analytic framework based on Self-Organizing Map (SOM) machine learning to study large scale patient data sets. The potency of the approach is demonstrated in a case study using gene expression data of more than 200 mature aggressive B-cell lymphoma patients. The method portrays each sample with individual resolution, characterizes the subtypes, disentangles the expression patterns into distinct modules, extracts their functional context using enrichment techniques and enables investigation of the similarity relations between the samples. The method also allows to detect and to correct outliers caused by contaminations. Based on our analysis, we propose a refined classification of B-cell Lymphoma into four molecular subtypes which are characterized by differential functional and clinical characteristics.

Gray Zone Lymphoma (GZL) With Features Intermediate Between Classical Hodgkin Lymphoma (cHL) and Diffuse Large B-Cell Lymphoma (DLBCL): A Large Retrospective Multicenter Analysis Of Clinical Characteristics, Treatment, Outcomes, and Prognosis In The Current Era

▪ BackgroundThe WHO recognizes a category of B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and cHL, which is commonly referred to as GZL. This is an uncommon entity that is reported to present primarily with mediastinal involvement; there is a paucity of data describing non-mediastinal presentations. Furthermore, treatment of this entity is challenging due to disease heterogeneity, lack of data regarding prognostication, and no standard guidelines for management. MethodsWe performed a multicenter retrospective analysis of newly diagnosed GZL patients (pts) treated from 2001-2012 at 18 North American academic centers. Inclusion criteria included availability of clinical information as well as minimum follow up of 12 months for non-relapsing pts. Diagnosis was established by institutional expert pathology review. We examined detailed pt characteristics, treatment and outcome, and we determined prognostic factors associated with survival on univariate and multivariate Cox regression analyses. Results100 pts with GZL were identified; 4 were excluded for inadequate follow-up. Of 96 cases, median age was 39 years (19-86) with 23% of pts age ≥ 60 years; M:F ratio was 1.5:1. Clinical characteristics at diagnosis were as follows: 52% stage III/IV; 56% B symptoms; 89% ECOG PS 0-1; 38% elevated LDH; 31% hypoalbuminemia, 62% anemia; 13% bone marrow involvement; 24% bulky disease >10cm (26% stage I/II and 20% stage III/IV had bulk disease); and 23% of pts had IPI 3-5 and 18% IPS 4-7. Notably, 44% of pts presented with mediastinal involvement (MGZL), while 56% had systemic disease without mediastinal involvement (NMGZL). Compared with NMGZL, pts with MGZL were younger (37 vs 50 years, P<0.0001) and more frequently had stage I/II disease (77% vs 17%, P=0.0001). Further, MGZL had lower IPS (12% 3-7) and IPI scores (12% 3-5) compared with NMGZL (44% IPS 3-7, P=0.0002; and 33% IPI 3-5, P=0.0006). The most common first-line therapy for all pts was R-CHOP (n=48), followed by ABVD (n=25), R-EPOCH (n=10), CHOP (n=5), BEACOPP or hyperCVAD (n=5), and other (n=2); 69% of pts received rituximab as part of first-line therapy and 31% received consolidative radiotherapy (RT) (RT: 70% of MGZL and 13% of NMGZL). The overall response rate (ORR) to first-line therapy was 70% with 58% achieving a complete remission (CR); 27% of pts had primary refractory disease. While there was a trend for improved CR rate for pts who received rituximab as part of first-line therapy (65% vs 40% for those not receiving rituximab, P=0.07), there were no significant differences in response based on other individual treatment regimens or modalities. At a median follow-up of 25 months (8-109), the 2-year progression-free survival (PFS) and overall survival (OS) for all pts were 41% and 84%, respectively (Figure 1). PFS and OS were superior for pts with stage I/II disease compared with stage III/IV (PFS: 52% vs 32%, respectively, P=0.02; OS: 97% and 71%, respectively, P=0.001). On univariate analysis, clinical factors that predicted PFS and OS are detailed in Table 1. Interestingly, despite having lower risk features, the PFS or OS for MGZL did not differ from NMGZL. On multivariate regression analysis for PFS, elevated LDH was the only factor that predicted poorer outcome (HR 2.01 (95% CI 0.99-4.09), P=0.05). Several factors were significant for inferior OS including: presence of B symptoms (HR 17.41 (95% CI 1.53-197.57), P=0.02), hypoalbuminemia (HR 8.09 (95% CI 1.37-47.83), P=0.02), and stage 4 vs 1-3 disease (HR 21.39 (95% CI 2.90-157.74), P=0.003). [Display omitted] [Display omitted] ConclusionsTo the best of our knowledge, this is the largest series of GZL reported to date. We describe a new clinical subtype (NMGZL), which has distinct characteristics, but similar outcomes as MGZL. Within the limitations of a retrospective analysis, overall PFS appeared inferior to that observed in cHL and DLBCL, though OS was excellent, suggesting in part the success of salvage therapy. An elevated LDH was associated with worse PFS, while there were no differences seen based on clinical presentation or initial therapy. Further, there were several clinical factors identified (i.e., B symptoms, albumin, and stage) that strongly predicted OS. Continued examination both biologically and clinically of this unique subset of lymphoma is warranted. Disclosures:No relevant conflicts of interest to declare.

Long Term Follow-Up Of De Novo Or Minimally Treated Burkitt Lymphoma/Leukemia (BL/B-ALL) After Frontline Therapy Per The Hyper-CVAD Regimen With Or Without Rituximab: 20-Year Cumulative Experience

BackgroundIncorporation of the anti-CD20 monoclonal antibody rituximab into intensive, multi-agent chemotherapy regimens has been widely applied as frontline therapy of BL/B-ALL. We previously reported significant improvements in disease-free (DFS) and overall survival (OS) rates with the addition of rituximab to hyper-CVAD compared with the historical experience. We now report a cumulative update of the findings over a 20-year period. Methods52 patients (pts) with newly diagnosed non-HIV BL (n=12) or B-ALL (n=40) were treated with hyper-CVAD and rituximab from February 2000 to June 2013. Chemoimmunotherapy was administered as previously described (Thomas DA et al, Cancer 2006:106; 1569-80). A separate cohort (n=9) with bcl-2 expression was excluded since they represented the category of B-cell lymphoma, unclassifiable, with intermediate features between diffuse large B-cell lymphoma and BL as per the 2008 revision of the WHO classification. Median age was 41 yrs (range, 17–77); 11 (21%) were aged 60 yrs or older. Six of the 52 pts were inevaluable for response: 3 were enrolled in complete remission (CR) after pretreatment with one cycle of chemotherapy and 3 had surgical resection of the tumor mass without evidence of residual disease. Seven (13%) had CNS involvement at presentation. Lactate dehydrogenase (LDH) level (ULN > 618 U/L) was elevated in 40 (77%). Outcome of the chemoimmunotherapy group was compared to historical experience with 44 pts treated with hyper-CVAD without rituximab from August 1992 to January 2000. ResultsAll evaluable pts responded; 42 of 44 (95%) achieved CR and 2 achieved partial response. All 11 pts aged 60 yrs or older achieved CR. After a median follow up of 90 months, 10 (19%) pts relapsed with only one survivor (late relapse after 7 yrs successfully salvaged with DA-EPOCH-R). Twelve (29%) pts died in CR from infections (n=4), other malignancies (n=4), other preexisting comorbid medical conditions (n=2), or unknown causes (n=2). Overall 5-yr DFS and OS rates were 70% and 70% respectively, improved compared with corresponding historical cohort rates of 60% and 51%. Six pts developed secondary dyscrasias (1 with acute myelogenous leukemia [AML] at 7 yrs, 1 with t(8;21) AML at 3 yrs, 1 with monosomy 7 AML at 3 yrs, 3 with myelodysplastic syndrome (range 1-8 yrs). Toxicity profile was similar to hyper-CVAD alone. In the cohort (n=9) of bcl-2 positive dual hit lymphoma/leukemia (DHL) typically associated with poor prognosis, the 5-yr DFS and OS rates were 71% and 56% respectively; 4 were long-term survivors beyond 5 years without disease recurrence. ConclusionsThe incorporation of rituximab into the hyper-CVAD regimen has improved outcomes for de novo BL/B-ALL, with achievement of respectable cure rates. Bortezomib has been incorporated for the DHL subset in an effort to improve the results. Later generation anti-CD20 monoclonal antibodies such as ofatumumab have supplanted rituximab. Investigation of other novel monoclonal antibodies such as blinatumomab or inotuzumab for BL/B-ALL is clearly warranted. Disclosures:No relevant conflicts of interest to declare.

The Impact of MYC Rearrangements and “Double Hit” Abnormalities in Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is heterogeneous. Gene expression profiling (GEP) has identified two principal subtypes: germinal center B cell (GCB) and activated B cell (ABC). Most DLBCL cases are distinct from Burkitt lymphoma (BL), but a subset of tumors has a GEP profile between BL and DLBCL, suggesting a spectrum. In parallel, the 2008 World Health Organization (WHO) classification included the category of B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL (BCL-U). MYC rearrangement and potential synergy with other genetic aberrations, particularly BCL2 or BCL6, so-called double hit lymphoma, have also been studied in DLBCL and gray zone lymphoma. These subsets have been associated with a poor patient outcome, with the data being strongest for MYC/BCL2 double hit lymphomas. This review summarizes the literature on the impact of MYC rearrangement, as well as MYC/BCL2 double hit, in patients with DLBCL and BCL-U. We also emphasize the evolving nature of these concepts, and outline suggestions for future studies.

I. Pathological and clinical diversity in diffuse large B‐cell lymphoma

I. Pathological and clinical diversity in diffuse large B‐cell lymphoma

B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma: Report of a case in the oral cavity

B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma (DLBCL/BL) is a new category of B-cell lymphoma according to the 4 th edition of the World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues (2008). The following report presents a case of this rare, newly described entity on the palate of a 59 year-old male.

Rituximab Plus Dose Intense Rapid-Cycling Chemotherapy with Intrathecal CNS Prophylaxis in Patients with Burkitt Lymphoma (BL) and Intermediate Unclassifiable Diffuse Large B-Cell Lymphoma/BL: Single Institution Experience

Abstract 1631Introduction. Burkitt Lymphoma (BL) and the novel category of B-cell lymphoma, unclassifiable, with features intermediate between BL and diffuse large B-cell lymphoma (intermediate DLBCL/BL) listed in the 2008 WHO classification, are mature B-cell non-Hodgkin lymphomas. They were characterized by a high degree of proliferation with an aggressive clinical course. With the introduction of dose intense, rapid-cycling chemotherapy (Magrath 1996), mainly when supplemented with Rituximab, the prognosis of BL was improved. Conversely, the issue of intermediate DLBCL/BL treatment is still a matter of debate. On this basis, we conducted a retrospective analysis to investigate the outcome of adult patients with BL and intermediate DLBCL/BL treated in a single hematological center. Methods. We retrospectively analyzed 23 adult patients divided in two groups according to histological diagnosis treated with Rituximab plus dose intense rapid-cycling chemotherapy with intrathecal CNS prophylaxis. Group 1: 18 adult BL patients, including three with a diagnosis of L3 acute lymphoblastic leukemia, treated according to CODOX-M/IVAC regimen including Cyclophosphamide, Doxorubicin, Vincristine, Methotrexate, Ifosfamide, Etoposide and high dose Cytarabine in association with Rituximab and intrathecal liposomal Cytarabine (R-CODOX-M/IVAC). Group 2: five intermediate DLBCL/BL, treated with Rituximab intensified CHOP with intrathecal Methotrexate followed by high dose Cytarabine and Mitoxantrone and high dose chemotherapy with autologous stem cell transplantation (R-HDC plus ASCT) or with R-CODOX-M/IVAC. Results. Group 1 included 18 patients with a median age of 45 years (range 29–74), stage IV in 14 cases (78%), performance status (PS) 2 in 14 (78%), LDH upper normal value in 13 (72%), bone marrow involvement in eight (44%), B symptoms in eight (44%) and liquor positivity at citoflussimetry in one (5%). Between 2006 and 2011 all 18 patients were treated according to R-CODOX-M/IVAC. Group 2 included five patients with median age of 47 years (range 32–58), stage IV in four patients (80%), PS 2 in all patients, LDH upper normal value in four (80%) bone marrow involvement in three (60%), B symptoms in three (60%) and liquor positivity at citoflussimetry in two (50%). Between 2008 and 2011 two patients were treated with R-HDC plus ASCT while the other three patients were treated with R-CODOX-M/IVAC regimen. All 18 BL patients of group 1 were evaluable for response: 15 patients were in persistent complete remission (CR) and three died of progressive disease. With a median follow-up of 70.3 months, progression free survival and overall survival were 76.5% and 80.3%, respectively. Therapy was well tolerated, with no significant acute and late treatment related toxicities and no toxic deaths. In group 2 the two patients treated with R-HDC plus ASCT died of progressive disease; of the three patients treated with R-CODOX-M/IVAC regimen, one died of early relapse disease occurred three months after achieving CR and two are still on therapy. Conclusions. Our data suggest that in BL R-CODOX-M/IVAC is a safe and highly effective therapeutic regimen providing a high rate of persistent CR. Within the limits of a small sample size, in our experience, patients with intermediate DLBCL/BL have a clinical aggressive disease with a poor prognosis regardless of the type of treatment. Additional and larger studies are warranted to clarify the behavior of this new histological entity and develop novel and efficacy therapeutic approaches. Disclosures:Vitolo:Roche Italy: Speakers Bureau; Celgene: Speakers Bureau; Jannsen-Cilag: Speakers Bureau.

Lymphoma with Features Intermediate Between DLBCL and Burkitt Lymphoma: Better Outcome with Intensive Chemotherapy Regimens

Abstract 2710Introduction Recent refinement in B-cell lymphoma classification by the WHO in 2008 has defined an entity that exists in the gray zone between diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). Varying in morphology, immunohistochemical, or genetic features, B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL (Intermediate DLBCL/BL) has been reported to have a poor clinical outcome. We aim to describe the clinical factors affecting outcomes and compare therapy response in a representative population.Methods A retrospective search of the Nebraska Lymphoma Study Group Registry from 1983–2009 meeting the diagnostic criteria for Intermediate DLBCL/BL yielded clinical data at presentation, follow-up, and treatment information. Treatments were grouped as CHOP-like +/− Rituximab (R) vs. intensive regimens (e.g. CODOX-M +/− R, R-EPOCH). Diagnostic slides were re-reviewed to verify the diagnosis. Probabilities of progression-free survival (PFS) and overall survival (OS) were approximated using Kaplan-Meier method. Cox proportional regression analysis was used to evaluate the clinical variables associated with risk of treatment-failure and death.Results Our cohort of 63 patients had a median age of 69 (19–93), male sex in 49%, a Karnofsky performance status of at least 80 at time of diagnosis in 73%, an elevated serum lactate dehydrogenase (LDH) in 62%, and stage IV disease in 46%. International Prognostic Index (IPI) scores were low in 38%, low-intermediate in 27%, high-intermediate in 24% and high in 11%. The probability of PFS at 5 and 10 years was 25% (95% CI 15–37%) and 10% (95% CI 4–21%) respectively, with a median time to treatment-failure of only 5.7 months. The 5 and 10 year probability of OS was 32% (95% CI 21–44%) and 20% (95% CI 10–32%) respectively, with a median survival of 10.4 months. Univariate regression analysis showed the following factors to be associated with an increased risk for treatment-failure: Ann Arbor stage IV disease (HR 2.49, 95% CI 1.33–4.68); elevated LDH (HR 1.85, 95% CI 1.02–3.37) and having at least 2 extra-nodal sites (HR 2.12, 95% CI 1.12–4.04). The following factors were associated with an increased risk of death: elevated LDH (HR 2.03, 95% CI 1.08–3.81), stage IV disease (HR 1.88, 95% CI 1.00–3.45), and having at least 2 extra-nodal sites (HR 2.26, 95% CI 1.15–4.40). The IPI scores of low-intermediate, high-intermediate, and high risk were associated with treatment-failure (HR 2.01, 95% CI 1.00–4.11; 4.62, 95% CI 2.11–10.14; 6.11, 95% CI 2.31–16.17) respectively, and death (HR 2.57, 95% CI 1.23–5.37; 3.13, 95% CI 1.41–6.94; 8.30, 95% CI 3.07–22.43) respectively. The median OS of patients who received CHOP/CHOP-like regimens +/− R was 8.7 months, whereas those who received a more intensive regimen +/− R was 45 months (p=0.38). The median PFS was 5.4 months for CHOP/CHOP-like regimens +/− R and 52.3 months for a more intensive regimen (p=0.08) (Fig.1). [Display omitted] Summary Our analysis confirmed poor clinical outcome with stage IV disease, elevated serum LDH, at least 2 extra-nodal sites at presentation, or worse IPI score. There was a better outcome with intensive chemotherapy regimens. This study underscores the importance of early identification and proper treatment choice. Disclosures:No relevant conflicts of interest to declare.

Frequent Chromosome 1q Aberrations in HIV Associated B-Cell Lymphoma Unclassifiable with Intermediate Features Between Diffuse Large B-Cell Lymphoma and Burkitt Lymphoma,

Abstract 3572Human Immunodeficiency Virus (HIV) infection is known to be strongly associated with an increased risk of high grade B-Cell Lymphoma (such as Diffuse Large B-Cell Lymphoma and Burkitt Lymphoma). As South Africa has more than 5 million people living with HIV infection, this region sees a sharp increase in the diagnosis of high-grade lymphomas. HIV infection may associate with a number of atypical morphological features making it difficult to differentiate between classically described DLBCL and BL. As these two diseases have different prognosis and treatment, it is essential to accurately differentiate the type of disease and/or to diagnose the intermediate category of B-Cell Lymphoma, unclassifiable, with features intermediate between DLBCL and BL newly introduced in the 2008 WHO classification.In this study, we report on twelve patients (seven males and five females) who presented with high grade B cell lymphoma and a cell morphology comprising a mixture of medium to large cells that expressed B Cell markers. Patients' age ranged from 29 to 43 years old with a mean age of 34 years. Eight patients had a documented HIV positive status. Complex cytogenetic features associated with atypical morphologic features best fitted the diagnosis of B cell lymphoma unclassifiable, with features intermediate between DLBCL and BL.Conventional cytogenetics analysis revealed the presence of a complex karyotype in all cases. The chromosomes number varied from 46 to 49 with the exception of one case that had near-tetraploid cells (69 to 84 chromosomes). Ten cases had a t(8;14) classical Burkitt translocation involving the Immunoglobulin heavy chain gene as a partner, and one case had a variant Burkitt translocation t(8;22) involving the lambda light chain gene. Double hits were seen in two cases. In both cases, a translocation t(3;22)(q27;q11) rearranged the BCL6 gene in addition to a t(8;14). MYC and BCL6 genes rearrangements were confirmed using fluorescence in situ hybridization with the MYC and BCL6 break-apart probes (Abbott Molecular) and with the IGH/MYC/CEP probes. The most common secondary chromosomal aberration associated with a MYC rearrangement, was a chromosome 1 long arm structural abnormality present in nine cases, (75%) and resulting in a full trisomy 1q (n=3), or in partial duplication/ triplication of chromosome 1q (n=3), with both types of aberrations associated in 3 cases.Genome-Wide Affymetrix SNP6.0 array analysis was used to delineate chromosome 1q regions of gains. In brief, high molecular weight tumor DNA was extracted from tumor cells together with normal controls. DNA was processed and hybridized to the arrays according to the manufacturer's instructions. Data analysis was performed using the dChip software and Circulary Binary Segmentation. Copy number analysis using SNP arrays delineated three minimum regions of gains on the chromosome 1 long arm, 1q21.1q23.3, 1q24.1q24.2 and 1q32.1q32.2. The smallest region of amplification 1q24.11q24.2 included 27 genes of which the RCSD1 gene normally expressed in B-cells and previously found to be involved in acute B cell lymphoid leukemia (De Braekeleer et al 2007). These regions were smaller than 1q gains previously mapped by array comparative genomic hybridization in acute lymphoblastic leukemia and BL (Davidsson, et al 2007). Abnormalities of chromosome 7q were also non-randomly detected in four cases, in the form of trisomy 7q, or partial 7q duplication. Gains of 1q and 7q are known to occur in 20% and 10% of Burkitt lymphomas respectively (Boerma et al 2009; Scholtysik et al 2010).On the basis of these molecular cytogenetic features, we argue that these aggressive immunodeficiency associated, mostly t(8;14) positive lymphomas, represent advanced, clonally evolved forms of BL. These findings support the notion that there are distinguishable subgroups in DLBCL/BL intermediate lymphomas. Disclosures:No relevant conflicts of interest to declare.

Predictive Value of Blood and Bone Marrow Flow Cytometry in B-Cell Lymphoma Classification: Comparative Analysis of Flow Cytometry and Tissue Biopsy in 252 Patients

Predictive Value of Blood and Bone Marrow Flow Cytometry in B-Cell Lymphoma Classification: Comparative Analysis of Flow Cytometry and Tissue Biopsy in 252 Patients

Diffuse large B-cell lymphoma classification using linguistic analysis and ensembled artificial neural networks

The purpose of this study is to apply non-medical methods to classify two types of diffuse large B-cell lymphoma (DLBCL), which are the germinal-center type (GCB) and the activated B-cell type (ABC). The study materials are MicroRNAs (miRNAs) acquired from DLBCL patients. In order to achieve this goal, statistical methods ( i.e. linguistic analysis) and engineering method ( i.e. ensembled artificial neural networks (EANN)) have been independently used to do qualitative and quantitative analysis. On this basis, a novel noise elimination enhanced algorithm has been proposed to improve the efficiency of linguistic analysis, namely ensembled linguistic analysis. According to the results, the phylogenetic tree can achieve better performance than initial linguistic analysis. On the other hand, EANN model was established to perform the classification quantitatively, and sensitivity analysis (SA) for EANN was carried out to evaluate the significance ranking of the miRNAs and finally select the 5 most important miRNAs. Besides, classical linear and logistic regression models were developed for comparison with EANN classification results. The regression results were evidently worse than EANN model. This study proves that each lymphoma type has a distinctive pattern of miRNAs expression and the miRNAs expression pattern of ABC is more close to white noise than GCB. Both linguistic analysis and EANN model achieved accurate results; however the performance of EANN model for classification is much better. The 5 selected important miRNAs will be helpful for further study.

Strong BCL2 expression in Burkitt lymphoma is not uncommon in adults

The distinction between Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) is not always easy, so much so that the WHO 2008 Blue Book has incorporated a provisional category of "B-cell lymphoma, unclassifiable with features intermediate between DLBCL and BL." One of the immunohistochemical (IHC) markers used at times to differentiate between the two is IHC expression of BCL2, which was initially believed to be consistently negative in BL. Later it was recognized that weak BCL2 expression is still compatible with the diagnosis of BL. To verify or otherwise this current view this study was undertaken. We retrieved 39 confirmed cases of BL, in both children and adults. All these cases had typical morphology, IHC profile, and Mib-1 index that are typical of BL. All these cases were then stained with a monoclonal antibody against BCL2 oncoprotein, using 2-step Envision system. Out of 39 cases, 31 cases (79.4%) were completely negative for BCL2, whereas 5 (12.8%) were weak focal positive. However, another 4 (10.2%) cases did show strong diffuse cytoplasmic staining for BCL2. Fluorescent in-Situ hybridization (FISH) for t(14:18) was optimally done on 6 out of 9 cases. All these 4 cases were from adults with 3 out of 4 arising in the parotid region. Two out of 4 cases also showed t(8:14) on FISH. It was concluded that contrary to the common belief, strong BCL2 IHC expression is possible in typical BL in adults and cannot be absolutely relied upon to distinguish between BL and DLBCL.