Commentary on the WHO classification of tumors of lymphoid tissues (2008): ��Gray zone�� lymphomas overlapping with Burkitt lymphoma or classical Hodgkin lymphoma

The 2008 WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues has introduced two new categories of high-grade B-cell lymphomas: entities in which features of diffuse large B-cell lymphoma (DLBCL) overlap with Burkitt lymphoma (DLBCL/BL) or classical Hodgkin lymphoma (DLBCL/HL). The DLBCL/BL category encompasses cases that resemble Burkitt lymphoma morphologically, but have one or more immunophenotypic or molecular genetic deviations that would exclude it from the BL category; conversely, some cases have immunophenotypic and/or genetic features of BL, but display cytologic variability unacceptable for BL. Many of the cases in the DLBCL/BL category contain a translocation of MYC as well as either BCL2 or BCL6 (so-called double-hit lymphomas) and have a very aggressive clinical behavior. The DLBCL/HL category encompasses lymphomas that exhibit the morphology of classical Hodgkin lymphoma but the immunophenotype of DLBCL, or vice versa. Most DLBCL/HL cases described present as mediastinal masses, but this category is not limited to mediastinal lymphomas. These new categories acknowledge the increasing recognition of cases that display mixed features of two well-established diseases. Whether the existence of such cases reflects shortcomings of our current diagnostic armamentarium or a true disease continuum in which such hybrid or intermediate neoplasms actually exist remains to be determined.     

Diagnosis of Hodgkin's disease: an update on histopathological and immunophenotypical features

The Hodgkin lymphoma (HL) is a B-cell lymphoma, as was proved by molecular studies with single-cell PCR. Histologically, it is characterized by a minority of neoplastic cells, Reed-Sternberg cells and its variants, related to a variable non-neoplastic inflammatory background. Nowadays, (WHO classification) the following types of HL are recognized: Nodular Paragranuloma and the Classical Hodgkin Lymphoma, the latter including Nodular Sclerosis, Mixed Cellularity, Lymphocyte-rich Classical Hodgkin Lymphoma and Lymphocyte Depletion. Morphology together with immunohistochemical studies allows to classify the different forms of Hodgkin lymphoma and to make a differential diagnosis with non-Hodgkin lymphomas. All classical Hodgkin lymphomas are treated similarly, and chances for remission and survival are currently good. Molecular parameters should be added to the current classification and patients could benefit from new therapeutic targets.     

Diverse Hematological Malignancies Including Hodgkin-Like Lymphomas Develop in Chimeric MHC Class II Transgenic Mice

A chimeric HLA-DR4-H2-E (DR4) homozygous transgenic mouse line spontaneously develops diverse hematological malignancies with high frequency (70%). The majority of malignancies were distributed equally between T and B cell neoplasms and included lymphoblastic T cell lymphoma (LTCL), lymphoblastic B cell lymphoma (LBCL), diffuse large B cell lymphoma (DLBCL), the histiocyte/T cell rich variant of DLBCL (DLBCL-HA/T cell rich DLBCL), splenic marginal zone lymphoma (SMZL), follicular B cell lymphoma (FBL) and plasmacytoma (PCT). Most of these neoplasms were highly similar to human diseases. Also, some non-lymphoid malignancies such as acute myeloid leukemia (AML) and histiocytic sarcoma were found. Interestingly, composite lymphomas, including Hodgkin-like lymphomas, were also detected that had CD30⁺ Hodgkin/Reed-Sternberg (H/RS)-like cells, representing a tumor type not previously described in mice. Analysis of microdissected H/RS-like cells revealed their origin as germinal center B cells bearing somatic hypermutations and, in some instances, crippled mutations, as described for human Hodgkin lymphoma (HL). Transgene integration in an oncogene was excluded as an exclusive driving force of tumorigenesis and age-related lymphoma development suggests a multi-step process. Thus, this DR4 line is a useful model to investigate common molecular mechanisms that may contribute to important neoplastic diseases in man.     

Birth characteristics and risk of lymphoma in young children

BackgroundLymphoma is the third most common childhood malignancy and comprises two types, Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). The etiology of pediatric lymphomas is largely unknown, but has been suggested to have prenatal origins.MethodsIn this population-based study, California birth certificates were identified for 478 lymphoma cases diagnosed in children 0–5 years of age between 1988 and 2007; 208,015 controls frequency-matched by birth year were randomly selected from California birth records.ResultsCompared to non-Hispanic whites, Hispanic children had an increased risk of HL (odds ratio (OR) and 95% confidence interval (CI) 2.43 [1.14, 5.17]), and in particular, were diagnosed more often with the mixed cellularity subtype. For all types of lymphoma, we observed an about twofold risk increase with indicators for high risk pregnancies including tocolysis, fetopelvic disproportion and previous preterm birth. NHL risk doubled with the complication premature rupture of membranes (OR and 95% CI 2.18 [1.12, 4.25]) and HL with meconium staining of amniotic fluids (OR and 95% CI 2.55 [1.01, 6.43]).ConclusionThese data support previously reported associations between Hispanic ethnicity and HL and suggest that pregnancy related factors, such as intra-uterine infections and factors associated with preterm labor, may be involved in lymphoma pathogenesis.     

Expression and Functional Relevance of Cannabinoid Receptor 1 in Hodgkin Lymphoma

Background

Cannabinoid receptor 1 (CB₁) is expressed in certain types of malignancies. An analysis of CB₁ expression and function in Hodgkin lymphoma (HL), one of the most frequent lymphomas, was not performed to date.

Design and Methods

We examined the distribution of CB₁ protein in primary cases of HL. Using lymphoma derived cell lines, the role of CB₁ signaling on cell survival was investigated.

Results

A predominant expression of CB₁ was found in Hodgkin-Reed-Sternberg cells in a vast majority of classical HL cases. The HL cell lines L428, L540 and KM-H2 showed strong CB₁-abundance and displayed a dose-dependent decline of viability under CB₁ inhibition with AM251. Further, application of AM251 led to decrease of constitutively active NFκB/p65, a crucial survival factor of HRS-cells, and was followed by elevation of apoptotic markers in HL cells.

Conclusions

The present study identifies CB₁ as a feature of HL, which might serve as a potential selective target in the treatment of Hodgkin lymphoma.     

Lymphoma subtype incidence rates in children and adolescents: first report from Brazil

BackgroundLymphoma is the third most common pediatric malignancy. The purpose of this study was to analyze the incidence rates of lymphoma in children and adolescents in Brazil.MethodsAll cases of Hodgkin lymphoma (HL), non-Hodgkin lymphoma (NHL), and Burkitt lymphoma (BL) were extracted from 14 population-based cancer registries (PBCRs) from 2000 to 2005, and included children and adolescents 0–19 years old. Analyses included age-adjusted incidence rates (AAIRs) and age-specific incidence rates (ASIRs) by each PBCR. A social exclusion index (SEI) was built and used as proxy for socioeconomic status (SES) levels. Correlations between SES and incidence rates were investigated using Spearman's test.ResultsThe median incidence of lymphoma was 22.7/million. AAIRs of lymphomas varied from 12.9 (Salvador) to 34.5 per million (São Paulo). Median AAIR was 8.8/million, 9.8/million, and 2.9/million for NHL, HL, and BL, respectively. In all PBCRs except that of Recife, AAIR was slightly higher in males than females. The median ASIR was highest for HL (18.5/million) at 15–19 years for both genders. For NHL there were two peaks for ASIR: 11.1/million (1–4 years of age) and 13.2/million (15–19 years of age). The median ASIR for BL was highest among children aged 1–4 years (4.7/million) and in males. Higher SEI correlated with higher incidence of HL (P = 0.06), whereas rates of NHL and BL did not correlate with SEI. Borderline different incidence rates were observed in HL correlated with cities with higher SEIs.ConclusionIncidence rates of lymphomas in Brazil do not differ compared to rates reported worldwide, although SES differences deserve further investigation.     

The Kelch Protein KLHDC8B Guards against Mitotic Errors,Centrosomal Amplification,and Chromosomal Instability

The malignant cell in classical Hodgkin lymphoma (HL) is the binucleated giant Reed-Sternberg cell. Chromosomal instability and mitotic errors may contribute to HL pathogenesis; one potential mitotic regulator is the kelch protein KLHDC8B, which localizes to the midbody, is expressed during mitosis, and is mutated in a subset of familial and sporadic HL. We report that disrupting KLHDC8B function in HeLa cells, B lymphoblasts, and fibroblasts leads to significant increases in multinucleation, multipolar mitoses, failed abscission, asymmetric segregation of daughter nuclei, formation of anucleated daughter cells, centrosomal amplification, and aneuploidy. We recapitulated the major pathologic features of the Reed-Sternberg cell and concluded that KLHDC8B is essential for mitotic integrity and maintenance of chromosomal stability. The significant impact of KLHDC8B implicates the central roles of mitotic regulation and chromosomal segregation in the pathogenesis of HL and provides a novel molecular mechanism for chromosomal instability in HL.     

The Hodgkin and Reed/Sternberg cell

Hodgkin and Reed/Sternberg (HRS) cells are the hallmark cells of Hodgkin's lymphoma (HL). They are large, often multinucleated with a peculiar morphology and an unusual immunophenotype, that does not resemble any normal cell in the body. Despite their rarity in HL tissues, HRS cells are the clonal tumour cells of HL. HRS cells in nearly all cases of HL derive from B cells, and only rarely from T cells. Notably, the pattern of somatic mutations in their rearranged immunoglobulin V genes suggests that they are derived from pre-apoptotic germinal center B cells. The pathogenesis of HL is still largely unresolved, but it is now clear that aberrant activation of several signalling pathways (such as the NFkappaB pathway) is of key importance for HRS cell survival. HRS or HRS-like cells are also found in several other diseases, e.g. as rare intermingled cells in some non-Hodgkin lymphomas and in infectious mononucleosis.     

Immunosenescence and lymphomagenesis

One of the most important determinants of aging-related changes is a complex biological process emerged recently and called “immunosenescence”. Immunosenescence refers to the inability of an aging immune system to produce an appropriate and effective response to challenge. This immune dysregulation may manifest as increased susceptibility to infection, cancer, autoimmune disease, and vaccine failure. At present, the relationship between immunosenescence and lymphoma in elderly patients is not defined in a satisfactory way.This review presents a brief overview of the interplay between aging, cancer and lymphoma, and the key topic of immunosenescence is addressed in the context of two main lymphoma groups, namely Non Hodgkin Lymphoma (NHL) and Hodgkin Lymphoma (HL). Epstein Barr Virus (EBV) plays a central role in the onset of neoplastic lymphoproliferation associated with immunological changes in aging, although the pathophysiology varies vastly among different disease entities. The interaction between immune dysfunction, immunosenescence and Epstein Barr Virus (EBV) infection appears to differ between NHL and HL, as well as between NHL subtypes.     

Clonal relationship of relapsing lymphoid neoplasms

Lymphomas encompass a broad spectrum of neoplasias. Traditionally it has been assumed that recurrent neoplasia, especially lymphoma, represents a relapse of the original clone. However, this concept has been challenged. Here we present an overview of novel perceptions regarding the clonal relationship of relapsing lymphoid neoplasms, i.e. precursor cell acute lymphoblastic lymphoma/leukemia (ALL), so called non-Hodgkin lymphomas (NHL) and classical Hodgkin lymphoma (cHL) and discuss the potential implications of these findings. In ALL, approximately 10% of "relapses" were found to be clonally unrelated to the original disease. In NHL, small series and case reports showed the occurrence of meta- or synchronous lymphoid malignancies, which were of different clonal origin. In cHL, there is evidence that both early and late "relapses" may constitute to a certain proportion a novel neoplasm of different clonal origin too. These findings warrant further investigations in order to verify and strengthen the existing data and might have important clinical implications because novel clonally unrelated lymphomas imitating relapses could possibly be treatable with less aggressive regimens compared to true recurrences.     

Common germinal-center B-cell origin of the malignant cells in two composite lymphomas, involving classical Hodgkin's disease and either follicular lymphoma or B-CLL

BACKGROUND: Classical Hodgkin's disease (HD) and B-cell non-Hodgkin lymphoma (NHL) occasionally occur in the same patient. Such composite lymphomas represent interesting models to study the pathogenesis of B-cell lymphomas and the relationship between HD and B-cell NHL. MATERIALS AND METHODS: We analyzed two composite lymphomas (a combination of classical HD with follicular lymphoma [FL] and a combination of classical HD with B-cell chronic lymphocytic leukemia [B-CLL]) by micromanipulation of single cells from tissue sections and amplification of immunoglobulin V region genes for the clonal relationship of the tumor cells. RESULTS: In both cases, clonally related variable (V) genes with both shared as well as distinct somatic mutations were obtained from the two lymphomas, showing that in each of the cases the distinct tumor cells were members of a common germinal center (GC) B-cell clone. FL cells from two different lymph nodes of patient 1 showed a similar mutation pattern, suggesting that infiltration of these lymph nodes by tumor cells was not restricted to a particular FL cell or subclone. In the FL, a single cell was identified with a mutation signature indicating that premalignant cells can persist in the tissue. CONCLUSIONS: The cases presented here further underline the close relationship between HD and B-cell NHL and the role of the GC in lymphomagenesis. Whereas the latter was already suggested for FL and HD, the present study indicates that also in the B-CLL subset characterized by mutated Ig genes, important steps in malignant transformation happen in the GC, and that HRS cells can derive from CD5-positive B cells.     

Contribution of flow cytometric immunophenotyping to the evaluation of tissues with suspected lymphoma?

BACKGROUND: A critical analysis of the contribution of flow cytometric immunophenotyping (FCI) to the evaluation of lymph nodes and extranodal tissues with suspected lymphoma by a large, retrospective approach has not been reported previously and represents the purpose of this study. METHODS: A total of 278 lymph nodes and 95 extranodal tissue specimens submitted over a 2-year period with complete histologic, FCI, and immunohistochemical (IH) data formed the basis of the study. RESULTS: The FCI data contributed significantly to or was consistent with the final tissue diagnosis in the majority (94%) of the tissue samples. There is no well-described utility of flow cytometry markers for Hodgkin's lymphoma (HL) due to the usual scarcity of tumor cells in the final cell suspensions obtained from these tumors. However, the FCI data excluded non-Hodgkin's lymphoma (NHL) and suggested the possible usefulness of CD15 and CD30 by FCI in HL. In addition, immunophenotypic data by FCI in combination with touch imprint cytomorphology was useful in excluding a diagnosis of NHL in cases of nonhematopoietic malignancies and was particularly useful in defining the following hematopoietic tumors and malignancies: thymoma, T-cell lymphoblastic lymphoma, leukemia cutis, and plasma cell dyscrasia. Thus, IH was not essential for the diagnosis in these latter cases and was performed in only two cases (one thymoma and one plasma cell dyscrasia). Of interest, FCI supported the diagnosis in 3 cases of Ewing's sarcoma/primitive neuroectodermal tumor by detection of CD56 on the surface of the malignant cell. Only 11% of NHL were "negative" by FCI (i.e., an aberrant T-cell or monoclonal B-cell population was not identified). Reasons for these discrepancies included partial tissue involvement by the NHL with sampling differences, T-cell rich or lymphohistiocytic-rich variants with a small population of monoclonal B cells, marked tumoral sclerosis, poor tumor preservation, and T-cell NHL without an aberrant immunophenotype. Only 60% of CD30+ anaplastic large cell lymphomas (ALCL) were CD30+ by FCI. CONCLUSIONS: FCI data should always be correlated with light microscopy if no FCI abnormalities are detected; IH may need to be performed in selected cases. It is less necessary to perform microscopic examination of tissues when the FCI data are positive and indisputable. However, in selected cases in which FCI data is diagnostic, microscopic observations may provide additional information due to sampling.     

乳腺恶性血液病的病理类型、临床特点及生存分析

目的:探讨乳腺恶性血液病的病理分型、患者的临床特征及预后。方法:回顾性分析2014年1月至2019年1月空军军医大学西京医院收治的33例乳腺恶性血液病患者的病理分型、临床特征及预后。结果:33例患者中,32例为女性,1例为男性,平均年龄为45.5岁(12-78岁)。经病理确诊29例(29/33,87.9%)为非霍奇金淋巴瘤,其中弥漫大B细胞淋巴瘤(18/29,62.1%)最为常见,其次是NK/T细胞淋巴瘤(3/29,10.3%),B淋巴母细胞白血病/淋巴瘤(2/29,6.8%),而伯基特淋巴瘤、滤泡淋巴瘤、原发皮肤间变大细胞淋巴瘤各1例(1/29,3.4%),其余3例未进一步分型。此外,1例(1/33,3.0%)霍奇金淋巴瘤,3例(3/33,9.1%)急性白血病复发累及乳腺。原发性乳腺恶性血液病为19例(57.6%),继发性为14例(42.4%),病变主要累及右侧乳腺(18例,54.5%),其次为左侧(10例,30.3%),双侧均累及的为少数(5例,15.2%)。19例原发性乳腺恶性血液病均为淋巴瘤,与14例继发性乳腺恶性血液病相比,其血小板计数明显升高(P=0.004),β2-MG显著降低(P=0.049),B症状少(P=0.017),Ann Arbor分期主要为Ⅰ-Ⅱ期(P<0.01),骨髓受累少(P<0.01)等特点。生存分析提示原发性乳腺恶性血液病患者比继发性患者生存期更长(HR=9.846,P=0.002)。恶性血液病累及骨髓可导致生存期显著缩短(HR=6.434,P<0.01)。结论:乳腺恶性血液病患者以中年女性为主,原发性乳腺恶性血液病比继发性发病率高(分别为57.5%和42.5%),最常见的病理类型为弥漫大B细胞淋巴瘤,病变主要累及右侧乳腺。与继发性乳腺恶性血液病相比,原发性乳腺恶性血液病患者具有血小板计数相对更高,β2-MG水平更低,往往不伴B症状,Ann Arbor分期主要为Ⅰ-Ⅱ期,骨髓不受累,且生存期显著延长等特点。此外,恶性血液病累及骨髓提示预后不良。     

Aurora B kinase in Hodgkin lymphoma: immunohistochemical pattern of expression in neoplastic Hodgkin and Reed-Sternberg cells

Aurora B is a member of the chromosomal passenger complex, which is essential for proper completion of mitosis and cell division (cytokinesis). Inappropriate chromosomal segregation and cytokinesis due to deregulated expression of chromosome passenger proteins may lead to aneuploidy and cancer including lymphomas. According to our knowledge there are extremely limited studies investigating the immunohistochemical expression of Aurora B in tumor specimens of Hodgkin lymphoma. Our purpose was to characterize the expression of Aurora B in biopsies of Hodgkin lymphomas, and to evaluate the pattern of immunoreactivity in neoplastic Hodgkin and Reed-Sternberg cells (RS cells). We examined Aurora B immunoreactivity in paraffin sections of 15 samples of Hodgkin lymphomas, obtained from 15 patients, 8 men and 7 women. Ten were of nodular sclerosis type and five were of mixed cellularity. Our results showed immunoexpression of Aurora B in mononuclear lymphoid cells as well as in bi- and multinucleated RS cells. In addition, positive neoplastic cells in mitosis were observed, whereas a subpopulation without evidence of immunoreaction was also detected in each case. Taken together our results point to a possible association between Aurora B expression and mitotic deregulation in Hodgkin lymphoma, which may provide novel targets for treatment.     

Spatial Analysis of Childhood Cancer: A Case/Control Study

BackgroundChildhood cancer was the leading cause of death among children aged 1-14 years for 2012 in Spain. Leukemia has the highest incidence, followed by tumors of the central nervous system (CNS) and lymphomas (Hodgkin lymphoma, HL, and Non-Hodgkin’s lymphoma, NHL). Spatial distribution of childhood cancer cases has been under concern with the aim of identifying potential risk factors.ObjectiveThe two objectives are to study overall spatial clustering and cluster detection of cases of the three main childhood cancer causes, looking to increase etiological knowledge.MethodsWe ran a case-control study. The cases were children aged 0 to 14 diagnosed with leukemia, lymphomas (HL and NHL) or CNS neoplasm in five Spanish regions for the period 1996-2011. As a control group, we used a sample from the Birth Registry matching every case by year of birth, autonomous region of residence and sex with six controls. We geocoded and validated the address of the cases and controls. For our two objectives we used two different methodologies. For the first, for overall spatial clustering detection, we used the differences of K functions from the spatial point patterns perspective proposed by Diggle and Chetwynd and the second, for cluster detection, we used the spatial scan statistic proposed by Kulldorff with a level for statistical significance of 0.05.ResultsWe had 1062 cases of leukemia, 714 cases of CNS, 92 of HL and 246 of NHL. Accordingly we had 6 times the number of controls, 6372 controls for leukemia, 4284 controls for CNS, 552 controls for HL and 1476 controls for NHL. We found variations in the estimated empirical D(s) for the different regions and cancers, including some overall spatial clustering for specific regions and distances. We did not find statistically significant clusters.ConclusionsThe variations in the estimated empirical D(s) for the different regions and cancers could be partially explained by the differences in the spatial distribution of the population; however, according to the literature, we cannot discard environmental hazards or infections agents in the etiology of these cancers.     

Primary non-Hodgkin's lymphoma of the breast: a case report

Extranodal non-Hodgkin's lymphoma (NHL) of the breast is a rare entity. It represents 0.04-1.1% of malignant tumors of the breast. 1.7-2.2% of extranodal lymphomas and 0.7% of all NHL. However, primary NHL (PNHL) is the most frequent hematopojetic tumor of the breast. CASE: A 23-year-old woman presented with a mass in the left breast for 3 months followed by enlarged left axillary lymph nodes. Mammography showed a diffuse increase in the density of the left breast. Other investigations were unremarkable. Both fine needle aspiration cytology (FNAC) and histopathology were diagnostic of NHL. Immunohistochemistry was confirmatory of NHL, diffuse large cell type, of B-cell lineage. CONCLUSION: Primary and secondary lymphomas of the breast, though rare, should be considered in the differential diagnosis of breast malignancies. PNHL of the breast is usually right sided, but this patient had left breast involvement. Diagnosis by FNAC was successful as the cytologic picture is similar to that of any other lymphoid or extranodal NHL. When histopathology and immunohistopathology are conclusive, FNAC, supplemented by immunocytochemistry, can be applied as a simple, reliable and cost-effective tool in the early diagnosis of breast lymphomas.     

Immunological microenvironment gene expression in patients with diffuse large B cell non Hodgkin lymphoma

BackgroundNon Hodgkin lymphoma (NHL) is one of the immune system cancers. The occurrence and progression of malignant lymphomas depends on cellular pathways deregulation. Understanding the relationship between the immune system at the genetic level and malignant transformation is critical to reach its etiology.ObjectiveThe aim of this work is to evaluate the expression of five immune related genes (PD-1, FOXP3, GrA, GrB and CD11c) in patients with diffuse large B cell non Hodgkin lymphoma (DLBCL).Materials and methodsThis study was conducted on fifty patients with DLBCL and fifty sex and age matched apparently healthy subjects. The participants were subjected to these laboratory investigations: complete blood count, serum lactate dehydrogenase and β2microglobulin (β₂M) levels and determination of PD-1, FOXP3, GrA, GrB and CD11c gene expressions.ResultsThe results of this study revealed that PD-1, FOXP3, GrA, GrB and CD11c gene expressions were significantly increased in DLBCL patients.ConclusionPatients with DLBCL have variablePD-1, FOXP3,GrA, GrB and CD11cgene expressions levels, which are correlated with the overall survival (OS) indicating that they can be good predictors of outcome in these patients.     

Establishment of a Therapeutic Anti-Pan HLA-Class II Monoclonal Antibody That Directly Induces Lymphoma Cell Death via Large Pore Formation

To develop a new therapeutic monoclonal Antibody (mAb) for Hodgkin lymphoma (HL), we immunized a BALB/c mouse with live HL cell lines, alternating between two HL cell lines. After hybridization, we screened the hybridoma clones by assessing direct cytotoxicity against a HL cell line not used for immunization. We developed this strategy for establishing mAb to reduce the risk of obtaining clonotypic mAb specific for single HL cell line. A newly established mouse anti-human mAb (4713) triggered cytoskeleton-dependent, but complement- and caspase-independent, cell death in HL cell lines, Burkitt lymphoma cell lines, and advanced adult T-cell leukemia cell lines. Intravenous injection of mAb 4713 in tumor-bearing SCID mice improved survival significantly. mAb 4713 was revealed to be a mouse anti-human pan-HLA class II mAb. Treatment with this mAb induced the formation of large pores on the surface of target lymphoma cells within 30 min. This finding suggests that the cell death process induced by this anti-pan HLA-class II mAb may involve the same death signals stimulated by a cytolytic anti-pan MHC class I mAb that also induces large pore formation. This multifaceted study supports the therapeutic potential of mAb 4713 for various forms of lymphoma.     

PCR clonality detection in Hodgkin lymphoma

B-cell clonality detection in whole tissue is considered indicative of B-cell non-Hodgkin lymphoma (NHL). We tested frozen tissue of 24 classical Hodgkin lymphomas (cHL) with a varying tumor cell load with the multiplex polymerase chain reaction (PCR) primer sets for IGH and IGK gene rearrangement (BIOMED-2). A clonal population was found in 13 cases with the IGH FR1 and/or FR2/FR3 PCRs. Using the IGK-VJ and IGK-DE PCRs, an additional six cases had a dominant clonal cell population, resulting in a detection rate of 79% in frozen tissue. Of 12 cases, also the formalin-fixed and paraffin-embedded (FFPE) tissue was tested. Surprisingly, in eight of the 12 FFPE cases with acceptable DNA quality (allowing PCR amplification of >200 nt fragments), the IGK multiplex PCRs performed better in detecting clonality (six out of eight clonal IGK rearrangements) than the IGH PCRs (four out of nine clonal rearrangements), despite a rather large amplicon size. There was no evidence of B-cell lymphoma during follow-up of 1 to 6 years and no correlation was found between the presence of a clonal result and Epstein–Barr virus in the tumor cells. Our results indicate that the present routine PCR methods are sensitive enough to detect small numbers of malignant cells in cHL. Therefore, the presence of a clonal B-cell population does not differentiate between cHL and NHL.