Pathogenesis Of Hodgkin's Disease Research Articles

Hodgkin disease risk: Role of genetic polymorphisms and gene–gene interactions in inflammation pathway genes

Inflammation is a critical component of cancer development. The clinical and pathological features of Hodgkin disease (HD) reflect an abnormal immunity that results from cytokines secreted by Reed-Sternberg cells and the surrounding tumor. Numerous studies have reported the association between genetic polymorphisms in cytokine genes and the susceptibility to different hematologic cancers. However, the effects of such SNPs on modulating HD risk have not yet been investigated. We hypothesized that gene-gene interactions between candidate genes in the anti- and pro-inflammatory pathways carrying suspicious polymorphisms may contribute to susceptibility to HD. To test this hypothesis, we conducted a study on 200 HD cases and 220 controls to assess associations between HD risk and 38 functional SNPs in inflammatory genes. We evaluated potential gene-gene interactions using a multi-analytic strategy combining logistic regression, multi-factor dimensionality reduction, and classification and regression tree (CART) approaches. We observed that, in combination, allelic variants in the COX2, IL18, ILR4, and IL10 genes modify the risk for developing HD. Moreover, the cumulative genetic risk score (CGRS) revealed a significant trend where the risk for developing HD increases as the number of adverse alleles in the cytokine genes increase. These findings support the notion that epigenetic-interactions between these cytokines may influence pathogenesis of HD modulating the proliferation of regulatory T cells. In this way, the innate and adaptative immune responses may be altered and defy their usual functions in the host anti-tumor response. Our study is the first to report the association between polymorphisms in inflammation genes and HD susceptibility risk.

Correlation between expression of MCM6, a new proliferative marker, and treatment outcome in patients with Hodgkin's disease

e19547 Background: MCM6 is a proliferative marker, which in contrary to Ki67, is involved in all cell cycle phases, including early G1. We evaluated MCM6 expression in Hodgkin's disease (HD) patients in order to find any correlation between MCM6 expression and treatment outcome. Methods: Formalin-fixed paraffin-embedded lymph node specimens of 55 patients with HD treated with ABVD regimen (± radiotherapy) were assessed for MCM6 expression by IHC. The percentage of nuclear positivity in RS and mononuclear Hodgkin cells was evaluated in each case. Clinical data, response to treatment and relapse rates were obtained from patients’ medical records. These data were analyzed by SPSS software. Results: Mean MCM6 expression was 80.7% (ranging 35%-99%) with no significant difference between histology subtypes. In univariate analysis, MCM6 expression was not statistically significant for B-symptoms (P=0.27), sex (P=0.91), stage (P=0.18) and response to treatment (P=0.53), but was significant for age (P=0.008) (≤23 vs >23 yrs old). The MCM6 mean expression between relapsed and non-relapsed groups was marginally significant (21% vs 29.4%, P=0.057). In multivariate analysis, we evaluated MCM6 expression, B-symptoms, stage, response rate and age for relapse. None of risk factors were statistically significant predictor for relapse, including MCM6 expression (P=0.238), however, were significant regarding to response (P<0.001) and stage (P=0.048). We divided patients in 4 quartiles based on their MCM6 expression (Q1<74.25%, N=13, Q2=74.26–85.5%, N=14, Q3=85.6–91.75%, N=13, Q4>91.75%, N=12). Relapse and PFS were not significantly different between these quartiles (P=0.27 and P=0.83, respectively). Conclusions: Our study on a limited number of patients revealed MCM6 is not a strong predictor for treatment outcome in patients with HD. Our findings can be possibly explained by early G1 arrest of tumor cells and the role of cytokine production in pathogenesis of HD. We believe determining the accurate predictive role of proliferative markers needs to be focused on the markers which are exclusively involved in S phase. No significant financial relationships to disclose.

Genetic polymorphisms in DNA repair genes as modulators of Hodgkin disease risk

Although the pathogenesis of Hodgkin disease (HD) remains unknown, the results of epidemiologic studies suggest that heritable factors are important in terms of susceptibility. Polymorphisms in DNA repair genes may contribute to individual susceptibility for development of different cancers. However, to the authors' knowledge, few studies to date have investigated the role of such polymorphisms as risk factors for development of HD. The authors evaluated the relation between polymorphisms in 3 nucleotide excision repair pathway genes (XPD [Lys751Gln], XPC [Lys939Gln], and XPG [Asp1104His]), the base excision repair XRCC1 (Arg399Gln), and double-strand break repair XRCC3 (Thr241Met) in a population of 200 HD cases and 220 matched controls. Variants were investigated independently and in combination; odd ratios (OR) were calculated. A positive association was found for XRCC1 gene polymorphism Arg399Gln (OR, 1.77; 95% confidence interval [95% CI], 1.16-2.71) and risk of HD. The combined analysis demonstrated that XRCC1/XRCC3 and XRCC1/XPC polymorphisms were associated with a significant increase in HD risk. XRCC1 Arg/Arg and XRCC3 Thr/Met genotypes combined were associated with an OR of 2.38 (95% CI, 1.24-4.55). The XRCC1 Arg/Gln and XRCC3 Thr/Thr, Thr/Met, and Met/Met genotypes had ORs of 1.88 (95% CI, 1.02-4.10), 1.97 (95% CI, 1.05-3.73), and 4.13 (95% CI, 1.50-11.33), respectively. XRCC1 Gln/Gln and XRCC3 Thr/Thr variant led to a significant increase in risk, with ORs of 3.00 (95% CI, 1.15-7.80). Similarly, XRCC1 Arg/Gln together with XPC Lys/Lys was found to significantly increase the risk of HD (OR, 2.14; 95% CI, 1.09-4.23). These data suggest that genetic polymorphisms in DNA repair genes may modify the risk of HD, especially when interactions between the pathways are considered.

The Pathology of Hodgkin's Disease: What's New?

From the viewpoint of the pathologist, there are three major issues concerning Hodgkin's disease (HD) that must be addressed. First is making the correct diagnosis; second is identifying any pathological features that may be of prognostic importance; and third is defining the identity of the neoplastic cell. Since Hodgkin's disease (HD) was first described, the origin of the Reed-Sternberg cell and the pathogenesis of HD have remained elusive. Recently developed techniques have allowed investigators to analyze the immunophenotype and genotype of Reed-Sternberg cells. The results of these studies include recognition that, in many cases, Reed-Sternberg cells are of lymphoid origin. Thus, although in most cases of HD the diagnosis is straightforward on routinely stained sections, the conceptual dividing line between HD and non-Hodgkin's lymphoma is not as sharp as it once seemed. Occasionally, there is difficulty in distinguishing between HD and non-Hodgkin's lymphoma. Nevertheless, fundamental differences in the clinical features, histology, immunophenotype, and genotype between non-Hodgkin's lymphoma and HD remain. The impact of histological features on prognosis are controversial, largely because of the excellent prognosis of most cases of HD.

The plateled-derived growth factor level (PDGF) in Hodgkin's disease and non-Hodgkin's lymphoma and its relationship disease activation

The research reported in this paper was designed to study the role of plateled-derived growth factor (PDGF) in Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NHL). The PDGF levels in 9 patients with HD and 12 NHL and in a control group consisting of 20 people, was measured by ELISA method. The PDGF values in the disease group of 19 patients were raised. The values of PDGF in the control group were 28.977±9?pg/ml, but were measured at 147.083±54?pg/ml in HD group and 131.487±56?pg/ml in NHL group (p<0.01). The observation of a 5-fold increase in PDGF values in the disease group when compared to the control group suggests that PDGF could itself be considered as a possible factor in the pathogenesis of HD and NHL. In order to support this, there is a need to design additional studies monitoring PDGF in larger number of patients at various stages of the disease.

No adverse effect of ABVD chemotherapy in a patient with chronic hepatitis C and Hodgkin’s disease

There is insufficient information on the effects of chemotherapy protocols for Hodgkin's disease (HD) and the course of coexisting hepatitis C virus (HCV) infection. A single literature case reported a patient with HD who developed fulminant hepatitis and hepatic coma after receiving chemotherapy. The case described here is of a female patient previously exposed to prolonged war stress, complicated by intravenous drug abuse and chronic hepatitis C. One year after diagnosis of HCV infection she was diagnosed with HD (nodular sclerosis type II, clinical stage IIIB). The patient received six cycles of ABVD chemotherapy (doxorubicin, bleomycin, vinblastine and dacarbazine) resulting in complete remission of HD. There was no hepatitis flare either during or after chemotherapy. In conclusion, there were no adverse effects of the ABVD regimen on the course of HCV infection in this patient who was successfully treated for HD. Because concurrent HCV infection and HD is extremely rare, we discuss here the possibility of the synergistic contribution of chronic war stress and hepatitis C infection in the pathogenesis of HD.

Nuclear factor kappaB-dependent gene expression profiling of Hodgkin's disease tumor cells, pathogenetic significance, and link to constitutive signal transducer and activator of transcription 5a activity.

Constitutive nuclear nuclear factor (NF)-κB activity is observed in a variety of hematopoietic and solid tumors. Given the distinctive role of constitutive NF-κB for Hodgkin and Reed-Sternberg (HRS) cell viability, we performed molecular profiling in two Hodgkin's disease (HD) cell lines to identify NF-κB target genes. We recognized 45 genes whose expression in both cell lines was regulated by NF-κB. The NF-κB–dependent gene profile comprises chemokines, cytokines, receptors, apoptotic regulators, intracellular signaling molecules, and transcription factors, the majority of which maintain a marker-like expression in HRS cells. Remarkably, we found 17 novel NF-κB target genes. Using chromatin immunoprecipitation we demonstrate that NF-κB is recruited directly to the promoters of several target genes, including signal transducer and activator of transcription (STAT)5a, interleukin-13, and CC chemokine receptor 7. Intriguingly, NF-κB positively regulates STAT5a expression and signaling pathways in HRS cells, and promotes its persistent activation. In fact, STAT5a overexpression was found in most tumor cells of tested patients with classical HD, indicating a critical role for HD. The gene profile underscores a central role of NF-κB in the pathogenesis of HD and potentially of other tumors with constitutive NF-κB activation.

MDM2 gene amplification and lack of p53 point mutations in Hodgkin and Reed-Sternberg cells: results from single-cell polymerase chain reaction and molecular cytogenetic studies.

Hodgkin's disease (HD) is the most common haematological malignancy after chronic lymphocytic leukaemia, but very little is known about its pathogenesis or the genetic events that contribute to the malignant phenotype of the tumour cells. p53 is assumed to play an important role in the pathogenesis of HD, based on the observation that p53 protein is frequently accumulated in Hodgkin and Reed-Sternberg (H & RS) cells. We investigated single H & RS cells from five different HD patients for point mutations at the genomic level using multiplex polymerase chain reaction amplification and subsequent sequencing. No point mutations were detected in 50 single H & RS cells analysed. Hence, accumulation of p53 protein cannot be explained by mutations within the gene. A genome-wide screening for genomic imbalances using comparative genomic hybridization revealed gain on chromosome 12q14, i.e. the mapping position of the MDM2 gene in several HD cases. Therefore, we assessed the copy number of the MDM2 gene using fluorescence in situ hybridization. In four out of six HD cases analysed, the copy number of the MDM2 gene was found to be increased. As gene amplification is frequently associated with protein overexpression, the observed accumulation of p53 in the nuclei of H & RS cells could be as a result of elevated MDM2 protein levels resulting in stabilization of p53 protein.

Midkine Expression in Reed-Sternberg Cells of Hodgkin's Disease

Midkine (MK) was originally cloned as a product of a retinoic acid-responsive gene. The rationale for studying MK expression is based on previous reports showing that it transforms 3T3 cells, and that it acts as an autocrine growth factor in Wilm's tumors, and that its overexpression has been associated with worse outcome in bladder carcinoma. Besides bladder carcinoma, its expression was reported in various sollid tumors. We investigated the expression of MK protein and/or MK gene in biopsied specimens from 40 patients with primary malignant lymphoma, 21 with Hodgkin's disease (HD) and 19 with non-Hodgkin's lymphoma (NHL). Reed-Sternberg (R-S) cells were stained positive in 10 of 16 HD cases evaluated by immunohistochemical method, whereas 18 of 19 NHL cases did not stain, and one B-cell NHL stained weakly positive. Immunostaining analysis was extended to established cell lines and to normal lymphocytes with or without lectin stimulation or with EB virus transformation. Among hematopoietic ceils examined, erythro- or megakaryoblastic leukemia cell lines (K562, MEG-01 and UT7) were positive, while normal lymphocytes (except the EB virus-transformed one) and most myeloid and lymphoid cell lines (except Raji cells) were negative. On the contrary, solid tumor cell lines showed high and strongly positive staining including cell lines derived from of lung gastric, colon, and a pancreatic cancer.Using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), which is suitable for the detection of weakly expressed mRNA, the relative ratio of MK mRNA to β-actin mRNA of samples was measured and compared in cases where RNA was available. The mean values of relative ratio (MK/β-actin) of HD were almost twice as those of NHL samples, peripheral blood T cells, and spleen B cells. Our findings showed that MK is expressed in Reed-Sternberg cells of HD, and that MK might play a role in the pathogenesis of HD.

Sex Steroid Receptors in Hodgkin's Disease

A case report of a dramatic therapeutic response of Hodgkin's disease (HD) to diethylstilbestrol (DES) in a man who was being treated for concurrent prostate cancer suggested that there also may be a role for sex steroids in the pathogenesis of HD (I). High levels of estrogen receptors (ER) comparable to those seen in breast carcinoma cells were detected in that patient's Hodgkin's biopsy specimen. In order to determine whether this patient was unique or whether sex steroid receptors commonly are present in HD specimens. we examined expression of ER and progesterone receptors (PR) in diagnostic tissue from pediatric (n=14) and adult (n=41) patients with HD using immunohistochemistry. None of the 55 samples expressed PR. 16/55 (29%) demonstrated weak nuclear 13 positivity, which was confined to germinal center and occasional mantle zone lymphocytes and was comparable to that seen in non-malignant control lymph nodes. 4/55 (7.3%) samples exhibited moderate positivity in Reed Sternberg cells, which in one case was nuclear. ER commonly are expressed weakly in some HD tumors unrelated to clinical stage or patient sex but arc generally limited to germinal center and mantle zone lymphocytes. A rare patient displays moderate cytoplasmic or nuclear ER in Reed-Sternberg cells.

Mutation of the p53 Gene Is Not a Typical Feature of Hodgkin and Reed-Sternberg Cells in Hodgkin's Disease

AbstractPoint mutations of the p53 tumor suppressor gene are a frequent finding in human carcinomas and are thought to be an important oncogenic event. In non-Hodgkin lymphomas, p53 mutations occur in a minor fraction of cases. However, conclusive data are still lacking for Hodgkin's disease (HD) where the analysis meets technical problems. The neoplastic tumor cell clone in HD is represented by the large Hodgkin and Reed-Sternberg (HRS) cells, which account for only a minority of all cells in the tumor tissue (often <1%). To identify putative HRS cell-specific mutations, single HRS cells were micromanipulated from frozen tissue sections of HD biopsy specimens. Exons 4 to 8 of the p53 gene (in which more than 90% of p53 mutations associated with human neoplasms occur) were amplified from these single cells and sequenced. Mutations of p53 were not found in HRS cells of any of 8 cases of HD analyzed. We conclude that mutation of the p53 gene is only rarely, if at all, involved in the pathogenesis of HD.

Apoptosis-related genes and proteins in Hodgkin's disease.

During recent years it has become increasingly evident that L&H cells in nodular lymphocytic predominance (LP) Hodgkin's disease (HD) and Hodgkin and Reed-Sternberg (H-RS) cells in approximately half the cases of classical HD originate from B-lymphocytes, and that H-RS cells in most of the remaining cases of classical HD express a null phenotype. The pathogenesis of HD is unknown. An association with Epstein-Barr virus (EBV) has been suggested and there are also indications that genes involved in programmed cell death (apoptosis) may be implicated. In this study, the expression of four apoptosis-related proteins (bcl-2, bcl-x, bax and p53) in 53 cases of HD was examined and the data were correlated with the genotype, the EBV status and the phenotype (B, T or null) of the neoplastic cells. The H-RS cells expressed a B-cell phenotype in 3/3 cases of nodular LP and in 19/ 50 (38%) cases of classical HD. The remaining cases showed a null-cell phenotype in 29/50 (58%) and a T-cell phenotype in 2/50 (4%). EBV was more often positive in B (14/19, 74%) than in null (7/29, 24%) type HD. The H-RS cells were bcl-2-positive in 19/53 (36%), bcl-x-positive in 17/53 (32%), bax-positive in 1/53, and p53-positive in 41/53 (77%) cases. No relationship was found between bcl-2 expression and EBV status, or between bcl-2 and bcl-x expression. A t(14;18) translocation was seen in 2 of 34 cases. P53 point mutations were not detected. Our findings indicate that nodular LP and classical HD originate from B-cells in a high proportion of cases. They also suggest a role for bcl-2, bcl-x and p53 in tumorigenesis. The pathogenesis is not known at this stage.

Paediatric Hodgkin's disease in Spain: association with Epstein-Barr virus strains carrying latent membrane protein-1 oncogene deletions and high frequency of dual infections.

The present report analyses the distribution of 30-base pair (bp) latent membrane protein-1 (LMP-1) oncogene deletions in 24 cases of Epstein-Barr virus (EBV)-positive paediatric Hodgkin's disease (HD) and 39 normal controls. The 30 bp deletion was identified in 19/24 paediatric HD cases (79.2%), of which seven (29.2%) showed the deleted fragment alone, whereas in the remaining 12 (50%) it was accompanied by the nondeleted fragment. Conversely, the deletion was found in 8/22 (36.4%) EBV-positive healthy children, in two (9.1%) of whom the deleted fragment was alone, and was coinfecting with the nondeleted fragment in the other six (27.3%). The LMP-1 deletion was significantly associated with paediatric HD, both including dual infections (P=0.006) or excluding them (P=0.01). Type 2 EBV was carried by 25% of HD children, whereas all controls harboured type 1 EBV. The 30 bp deletion was present in all the paediatric HD specimens that contained type 2 EBV, suggesting that a deleted type 2 EBV strain may be more tumourigenic than a nondeleted type 2 EBV strain. These findings indicate that EBV strains carrying a 30 bp deletion in the third exon of the LMP-1 oncogene may have a more important role in the pathogenesis of paediatric HD than full-length EBV strains. Dual infection by LMP-1 deleted and nondeleted EBV strains is a frequent event both in healthy children and in the paediatric HD population.

Expression of Epstein-Barr virus in patients with Hodgkin's disease in Taiwan.

The association of Epstein-Barr virus (EBV) with Hodgkin's disease (HD) is intimately related to socioeconomic status. The proportion of HD patients with EBV is high in developing countries but low in developed countries. The aim of this study was to delineate the association of EBV with HD in Taiwan. Tissues from 70 consecutive cases of HD were examined for the presence of EBV, for the latent membrane protein (LMP- 1) by immunohistochemistry, and for EBER-1 by in situ hybridization. There were 53 males and 17 females, with a mean age of 42 years (range, 7-75 years). Histologic subtypes included nodular sclerosis in 36 cases (51.4%), mixed cellularity in 26 (37.1%), lymphocyte predominance in 6, and lymphocyte depletion in 2. Overall, EBV was expressed in 44 cases (62.9%), with EBER-1 expression detected in 40 (57.1%) and LMP-1 detected in 38 (54.3%). The following histologic subtypes were associated with EBV: lymphocyte predominance in 1 of 6 cases (16.7%), nodular sclerosis in 23 of 36 cases (63.9%), mixed cellularity in 18 of 26 cases (69.2%), and lymphocyte depletion in 2 of 2 cases (100%). EBV association with HD is relatively high in Taiwan. Although EBV was detected in all subtypes and at all ages in this study, the low endemic incidence of HD in Taiwan suggests that other factors, besides EBV, play a role in the pathogenesis of HD.

NPM/ALK fusion mRNA expression in Hodgkin and Reed-Sternberg cells is rare but does occur: Results from single-cell cDNA analysis

The translocation t(2;5)(p23;q35) leads to the fusion of the nucleophosmin gene (NPM) on chromosome 5q35 to the recently described receptor kinase ALK on 2p23. It is characteristic of a subgroup of CD30+ large-cell anaplastic non-Hodgkin's lymphoma (ALCL). Since some cases of Hodgkin's disease (HD) and ALCL share common features, a common pathogenesis has been proposed in a report of the expression of NPM/ALK fusion mRNA in 11/13 Hodgkin's lymphomas. We approached this question by micro-manipulatory isolation of single Hodgkin and Reed-Sternberg (H-RS) cells and subsequent RT-PCR amplification of NPM/ALK fusion cDNA from these single cells. Specificity of cell selection was shown by the HD-specific pattern of EBV-gene expression in single H-RS cells. In 4 out of 7 cases, NPM/ALK fusion cDNA was detected in the RNA from whole lymph node tissue. In 2 out of 9 cases, NPM/ALK fusion sequences were amplified from single H-RS cells, albeit in a very low frequency (< 5%). These data indicate that NPM/ALK fusion transcripts do not play an early role in the pathogenesis of HD. Whether the rare expression of NPM/ALK is the result of clonal heterogeneity or an indication for clonal evolution and progression toward ALCL can only be answered by the repeated analysis of indicator cases during the course of the disease.

Neoplastic cells of Hodgkin's disease show differences in EBV expression between Kenya and Italy

The Epstein-Barr Virus (EBV) has been implicated in the pathogenesis of Hodgkin's disease (HD). However, the association of EBV with this disease varies greatly from series to series and from country to country. Epidemiological studies have shown differences in HD occurring in different parts of the world. In particular, it has been reported that HD in developing countries differs from HD in Western countries in terms of epidemiological, pathological and clinical characteristics. These discrepancies among populations suggest an interaction with environmental factors and a direct role of different etiological agents. At present, there are no data on the frequency of association of EBV with HD in equatorial Africa. In this study, a large series of HD cases have been collected at the University of Nairobi, Kenya, and at the Universities of Bologna and Siena, Italy. The cases have been reviewed and classified according to the REAL Classification and the presence of EBV has been assessed by in situ hybridization (ISH). A statistical difference in EBV expression was found between HD from Kenya and HD from Italy. EBV-positive neoplastic cells were detected in 92% of Kenyan cases, whereas only 48% of Italian cases showed EBER1/2 positivity in the neoplastic cells. Our results suggest that, in Kenya, EBV plays a more direct role in the pathogenesis of HD, as it does for endemic Burkitt lymphoma.

Analysis of the BCL-6 gene configuration in diffuse B-cell non-Hodgkin's lymphomas and Hodgkin's disease.

BCL-6 is a novel proto-oncogene that codes for a zinc-finger protein sharing homologies with many transcription factors. It has recently been shown that BCL-6 is involved in chromosome band 3q27 aberrations in non-Hodgkin's lymphomas (NHLs) and BCL-6 rearrangements have been detected in 34-45 per cent of diffuse large cell lymphomas with B immunophenotype. We have studied the BCL-6 gene configuration by Southern blot analysis in 60 cases of B-cell NHL and in 17 cases of Hodgkin's disease (HD). BCL-6 was rearranged in 15/46 (32.6 per cent) diffuse B-large cell lymphomas, mainly with centroblastic morphology, and in 2/11 (18.2 per cent) follicular (centroblastic-centrocytic) lymphomas. Conversely, all cases of HD, including four cases of lymphocyte predominant, nodular type (nodular paragranuloma), had a germline configuration. These findings confirm that BCL-6 is rearranged in a significant percentage of diffuse B-large cell lymphomas, suggesting that this proto-oncogene might have a pathogenetic role in this subset of NHLs, but our preliminary analysis suggests that BCL-6 lesions are not involved in the pathogenesis of HD. However, further investigations using more sensitive techniques are required to confirm these findings.

Low incidence of mbr bcl-2/JH fusion genes in Hodgkin's disease.

Lymph node biopsies from 140 cases of Hodgkin's disease (HD) and from 30 non-malignant lesions were screened for the presence of t(14;18) translocations involving the major breakpoint region (mbr) of the bcl-2 gene and the joining region (JH) of the immunoglobulin heavy chain gene, using a polymerase chain reaction (PCR) assay with subsequent nucleotide sequencing of amplified bcl-2/JH junctional regions. Expression of the bcl-2 protein within the Hodgkin and Reed-Sternberg (HRS) cells was investigated in 86 cases of HD by immunohistochemistry on cryostat or paraffin sections. Although bcl-2 expression could be found in a proportion of neoplastic cells in up to one-third of HD cases, the frequency of t(14;18) gene fusions detected by PCR was low. We identified such gene fusions in only 3 out of 140 (2 per cent) HD cases, one biopsy of which presented with four clonally distinct bcl-2/JH sequences. No t(14;18) was found in any of 30 reactive lymph node lesions. All fusion gene sequences were unique regarding the localization of the chromosome 14 and 18 breakpoints and the extranucleotide N-insertions. None of these gene fusions conformed to t(14;18) breakpoint sequences previously characterized in our laboratories. Our findings point to a mere coincidence in some cases of HD lesions and cells carrying a t(14;18) in the same biopsy and argue against a significant role of bcl-2 in the pathogenesis of HD.

Hodgkin and Reed-Sternberg Cells Do Not Carry T-Cell Receptor γ Gene Rearrangements: Evidence From Single-Cell Polymerase Chain Reaction Examination

Hodgkin and Reed-Sternberg (H&RS) cells are generally accepted to be the neoplastic cells of Hodgkin's disease (HD), even though they represent only a minority of the cellular infiltrate in affected tissues. Recent immunologic studies and Southern blot analyses of DNA extracted from whole lymph node tissue favored, but did not convincingly prove a lymphoid origin of H&RS cells. To detect rearrangements of the T-cell receptor gamma chain (TCR gamma) genes at the single-cell level as an indication of early T-cell lymphoid differentiation, we isolated H&RS cells by micromanipulation from cytospin preparations of fresh biopsy material. TCR gamma chain rearrangement was detected by polymerase chain reaction using four "forward primers" that were constructed corresponding to all four V families and two "reverse primers" corresponding to consensus sequences of J segments. Rearrangements of all V families in combination with the different J segments were detected in human peripheral blood and tonsillar T cells. Although rearrangements of TCR gamma chain genes were shown in single cells of 10 of 10 T-cell leukemias, no rearrangement of these genes was found in single H&RS cells from 13 consecutive patients with HD. Our results indicate that H&RS cells from the vast majority of cases are not derived from T cells. This finding may have implications for the pathogenesis of HD and the development of more effective treatment regimens.

Pathology of Hodgkin's disease.

This review addresses several current questions about Hodgkin's disease (HD): 1) Does HD represent a single disease or multiple diseases? 2) What is the role of cytokines in HD? 3) What is the nature of the Reed-Sternberg cell? 4) How are Epstein-Barr virus (EBV) and oncogenes (bcl-2, c-myc, and p53) involved in the pathogenesis of HD? Nodular lymphocyte predominance HD appears to be a distinct clinicopathologic entity. Cytokines attract inflammatory cells, induce fibrosis, upregulate oncogenes and adhesion molecules, cause systemic symptoms, and mediate immune suppression. Reed-Sternberg cells are derived from B and T lymphocytes in most instances, although an alternative origin from a follicular dendritic reticulum cell has been proposed. EBV is an etiologic agent in some but not all HD cases. EBV gene products confer a growth advantage on Reed-Sternberg cells. The bcl-2 and p53 oncogenes protect Reed-Sternberg cells from apoptosis and are not directly upregulated by EBV.