Non-neoplastic Lymphoid Tissues Research Articles

Immunohistochemical analysis of arachidonate 5-lipoxygenase expression in B-cell lymphomas: Implication for B cell differentiation and its analogy with lymphomagenesis.

Arachidonate 5-lipoxygenase (ALOX5) is a cardinal enzyme in the synthesis of leukotrienes, which are powerful immune-regulating lipid mediators. We previously reported that ALOX5 is preferentially expressed in B lymphocytes in the mantle zone of human lymphoid tissue. In the context of physiological relevance, the loss of the Alox5 gene in mice significantly impairs the development of follicular B helper T cells and antibody production. However, ALOX5 expression in B-cell lymphomas has not been investigated in detail. In this study, we examined ALOX5 expression in representative B-cell lymphomas and non-neoplastic lymphoid tissues by immunohistochemistry with a commercially available anti-ALOX5 antibody that can be used on formalin-fixed paraffin-embedded specimens. Interestingly, 22/22 cases of mantle cell lymphoma, 7/7 cases of chronic lymphocytic leukemia/small cell lymphoma, and 20/20 cases of follicular lymphoma expressed ALOX5. A small proportion of extranodal marginal zone lymphoma/mucosa-associated lymphoid tissue lymphoma or nodal marginal zone lymphoma cases were positive for ALOX5 (2/13 or 1/3, respectively). In contrast, no cases with diffuse large B-cell lymphoma, regardless of germinal center B cell (GCB) or non-GCB type, expressed ALOX5 (0/25 cases). These findings suggest that ALOX5 may be a novel marker for identifying the cell of origin of B-cell lymphoma. Further investigation is required to clarify the biological significance of ALOX5 expression in lymphoma cells.

SDHC Methylation Pattern in Patients With Carney Triad.

Carney triad is a multitumor syndrome affecting almost exclusively young women in a nonfamilial setting, which manifests by multifocal gastric gastrointestinal stromal tumors, paragangliomas, and pulmonary chondroma. The Carney triad-associated tumors are characterized by a deficiency of the mitochondrial succinate dehydrogenase enzymatic complex. Recently, it has been observed that the deficiency results from epigenetic silencing of the SDHC gene by its promoter hypermethylation. To elucidate anatomic distribution of SDHC promoter methylation in Carney triad patients and thus to shed some light on the possible natural development of this epigenetic change, both neoplastic and available non-neoplastic tissues of 3 patients with Carney triad were tested for hypermethylation at the SDHC promoter site. SDHC promoter hypermethylation was proven in all tumors studied. Lack of SDHC epigenetic silencing in the non-neoplastic lymphoid and duodenal tissue (ie, tissues not involved in the development of Carney triad-associated tumors) together with the finding of SDHC promoter hypermethylation in the non-neoplastic gastric wall favors the hypothesis of postzygotic somatic mosaicism as the biological background of Carney triad; it also offers an explanation of the multifocality of gastrointestinal stromal tumors of the stomach occurring in this scenario as well. However, the precise mechanism responsible for the peculiar organ-specific distribution of Carney triad-associated tumors is still unknown.

Fatty acid beta oxidation enzyme HADHA is a novel potential therapeutic target in malignant lymphoma

Cancer cells, including malignant lymphoma cells, alter their metabolism, termed “metabolic reprograming,” on initiation of malignant transformation as well as upon accumulation of genetic abnormalities. Here, to identify a novel therapeutic target involved in the metabolic changes during malignant lymphoma, we performed global analyses combined with shotgun proteomics, in silico database analysis, and clinic-pathologic analysis of nonneoplastic lymphoid tissue and malignant lymphoma tissue and verified the molecular functions in vitro. In total, 2002 proteins were detected from both samples and proteins related to fatty acid beta-oxidation (FAO) were detected more frequently in malignant lymphoma tissue. Consequently, the most frequently detected protein, the mitochondrial trifunctional enzyme subunit-alpha (HADHA), was identified as a potential target. Immunohistochemical analyses revealed that HADHA tended to be overexpressed in a high-grade subtype of malignant lymphoma tissue. Clinicopathologic study revealed that HADHA overexpression was correlated with significantly worse overall survival (P= 0.013) and was an independent prognostic predictor in diffuse large B-cell lymphoma (P= 0.027). In vitro, downregulation of HADHA negatively regulated cell growth by causing G0/G1 arrest (P= 0.0008) similar to treatment with etomoxir, an inhibitor of FAO (P= 0.032). Moreover, downregulation of HADHA increased the susceptibility to doxorubicin (P= 0.002) and etoposide (P= 0.004). Moreover, these phenotypes were confirmed in an HADHA knockout system. Thus, we provide a basis for a novel therapeutic strategy through the regulation of HADHA and FAO in patients with refractory malignant lymphoma.

Monoamine oxidase A is highly expressed in classical Hodgkin lymphoma.

Monoamine oxidase A (MAOA) is a mitochondrial enzyme that catalyzes oxidative deamination of neurotransmitters and dietary amines and produces H2 O2 . It facilitates the progression of gliomas and prostate cancer, but its expression and functional relevance have not been studied in lymphoma. Here, we evaluated MAOA in 427 cases of Hodgkin and non-Hodgkin lymphoma and in a spectrum of reactive lymphoid tissues by immunohistochemistry on formalin-fixed, paraffin-embedded specimens. MAOA was expressed by Hodgkin Reed-Sternberg (HRS) cells in the majority of classical Hodgkin lymphomas (cHLs) (181/241; 75%), with 34.8% showing strong expression. Weak MAOA was also noted in a minority of primary mediastinal large B-cell lymphomas (8/47; 17%) and in a mediastinal gray-zone lymphoma. In contrast, no MAOA was found in non-neoplastic lymphoid tissues, nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL; 0/8) or any other non-Hodgkin lymphomas studied (0/123). MAOA was more common in Epstein-Barr virus (EBV)-negative compared to EBV-positive cHL (p < 0.0001) and was especially prevalent in the EBV-negative nodular sclerosing subtype. Similar to primary human lymphoma specimens, most cHL-derived cell lines displayed MAOA activity, whereas non-Hodgkin-lymphoma-derived cell lines did not. The MAOA inhibitor clorgyline reduced the growth of L1236 cells and U-HO1 cells, and shRNA knockdown of MAOA reduced the growth of L1236 cells. Conversely, ectopic overexpression of MAOA increased the growth of MAOA-negative HDLM2 cells. Combined treatment with clorgyline and ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) was more effective in reducing cell growth than either regimen alone. In summary, MAOA is highly expressed in cHL and may reflect the distinct biology of this lymphoma. Further studies on the potential utility of MAOA as a diagnostic marker and therapeutic target are warranted. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Expression of the Class II and III Beta-Tubulin in Neoplastic and Non-Neoplastic Lymphoid Tissues

Aim:Abnormal expression patterns of beta-tubulin isotypes may provide a molecular rationale for the behaviour of lymphoma subtypes. In the present study class II and III beta-tubulin expression was assessed in non-neoplastic and neoplastic lymphoid tissues with reference to potential utility as new tumour biomarkers.Methods and results:In this cross-sectional study class II and III beta-tubulin expression was assessed in 304 neoplastic and 20 normal lymphoid tissues using qualitative and semi-quantitative immunohistochemistry. Class II beta-tubulin was found to be positive in the germinal centres, mantle zone and interfollicular regions of normal lymphoid tissues. It was also expressed in 15/15 (100%) lymphoblastic lymphomas, 229/231 (99%) mature B cell lymphomas, 22/22 (100%) T/NK-cell lymphomas and 36/36(100%) classical Hodgkin lymphomas. Class III beta-tubulin in contrast was germinal centre restricted and more selective, being found mainly in classical Hodgkin lymphomas (34/36 (94%)). It was also expressed in 58/171(34%) DLBCL, 11/12 (92%) mantle cell lymphomas and 6/6 (100%) Burkitt lymphomas. Other mature B cell, T/NK cell lymphomas and precursor lymphoblastic lymphomas were usually negative.Conclusions:Class II beta-tubulin shows ubiquitous expression in neoplastic and non-neoplastic lymphoisd tissues. In contrast, Class III beta-tubulin is germinal centre-restricted. Its consistent expression in classical Hodgkin lymphomas may point to use in the identification of Reed-Sternberg and Hodgkin cells. Its expression in a proportion of DLBCL, Burkitt and mantle cell lymphomas is of interest as this may be related to their aggressiveness.

Immunohistochemical analysis of the novel marginal zone B-cell marker IRTA1 in malignant lymphoma

Marginal zone lymphoma (MZL) is a low-grade B-cell lymphoma derived from marginal zone B cells. Because of a lack of specific immunohistochemical markers, MZL is mainly diagnosed based on the cytological appearance and growth pattern of the tumor. Marginal zone B cells were recently shown to selectively express immunoglobulin superfamily receptor translocation-associated 1 (IRTA1), but the antibody used in that study is not commercially available. We therefore investigated the IRTA1 expression in nonneoplastic lymphoid tissues and 261 malignant lymphomas, examining the ability of a commercially available antibody to accurately diagnose MZL. Among 37 MZLs, 23 of 25 extranodal MZLs of mucosa-associated lymphoid tissue (MALT lymphomas), 3 of 6 splenic MZLs and 3 of 6 nodal MZLs were positive for IRTA1. Among the 98 diffuse large B-cell lymphomas, 33 were positive for IRTA1, including 1 of 38 follicular lymphomas, and all precursor B-lymphoblastic (2/2) and T-lymphoblastic (7/7) leukemia/lymphomas. Other mature B-cell and T-cell lymphomas, and Hodgkin lymphoma were negative for IRTA1. In MALT lymphoma, positive cells were detected mainly in intraepithelial and subepithelial marginal zone B cells. In 1 case of grade 3 follicular lymphoma, IRTA1 was also expressed in the area of large cell transformation. When tumors were classified as germinal center B cell-like (GCB) or non-GCB using the algorithm of Hans, positive expression of IRTA1 was correlated significantly with non-GCB diffuse large B-cell lymphomas (P < .05). These results demonstrated the ability of the commercially available IRTA1 antibody to distinguish MALT lymphoma from other low-grade B-cell lymphomas.

Localization of collagen modifying enzymes on fibroblastic reticular cells and follicular dendritic cells in non-neoplastic and neoplastic lymphoid tissues

The aim of this study was to evaluate the localization of collagen modifying enzymes (CMEs) on fibroblastic reticular cells (FRCs) and follicular dendritic cells (FDCs) in non-neoplastic lymphoid tissues and various malignant lymphomas. The expression of prolyl 4-hydroxylase 1 (P4H1), lysyl hydroxylase 3 (LH3), and protein disulfide isomerase (PDI) was frequently observed on FRCs and FDCs in the germinal center (GC), except for the mantle zone. The expression of CMEs was lower in most lymphomas than in their respective postulated normal counterparts. The ratio of transglutaminase II+ FRCs/CD35+ FDCs was also lower in follicular lymphomas (FL) than in other lymphomas. The mRNAs of some CMEs (P4H1, prolyl 4-hydroxylase 3, LH3, and heat shock protein 47) were confirmed in almost all lymphomas. These results indicate that lymphoma cell proliferation suppresses/decreases the number of CMEs expressing FRCs and FDCs in most lymphomas.

Monoclonal antibody HBME-1 reacts with a minor subset of B cells with villous surface and can be useful in the diagnosis of hairy cell leukemia and other indolent lymphoproliferations of villous B lymphocytes

The Hector Battifora mesothelial epitope-1 (HBME-1) monoclonal antibody has been generated against human mesothelioma cells and recognizes a biochemically unknown membrane epitope. We have accidentally found that the HBME-1 reacts with scattered lymphocytes showing villous surface in hyperplastic lymphoid tissue. To evaluate its reactivity pattern, we have performed a consecutive immunohistochemical study in nonneoplastic bone marrow and lymphoid samples (n = 40), as well as in malignant lymphoproliferations (n = 427), including hairy cell leukemia (HCL) (n = 72), HCL variant (HCL-v) (n = 13), splenic diffuse red pulp small B cell lymphoma (SDRPL) (n = 8), splenic B cell marginal zone lymphoma (SMZL) (n = 59), and splenic B cell lymphoma/leukemia, not further classifiable on bone marrow morphology (SBCL) (n = 37) cases. The staining pattern of HBME-1 was compared to DBA.44. HBME-1(+) villous lymphocytes were constantly detected in low number in nonneoplastic lymphoid tissues. With multicolor immunofluorescence staining, HBME-1(+) lymphocytes showed a CD20(+)/CD79a(+)/IgM(+) B cell phenotype. In B cell lymphoproliferations of villous lymphocytes, HBME-1 reactivity was demonstrated in 96 % of HCL, 39 % of HCL-v, 50 % of SDRPL, 12 % of SMZL, and 19 % of SBCL cases. Nodal and extranodal marginal zone lymphoma cases were positive in 12 % of the cases. A small minority (4 %) of the other B cell lymphomas and no T cell lymphoma revealed tumor cell reactivity with HBME-1. In conclusion, our study has established that HBME-1 reacts with a minor subset of B lymphocytes and a small proportion of B cell lymphomas, which has not been described previously. We suggest that HBME-1 can be a useful marker in the diagnosis of HCL and other indolent lymphoproliferations of villous B lymphocytes.

PAX 8 Expression in Nonneoplastic Lymphoid Tissues

PAX 8 Expression in Nonneoplastic Lymphoid Tissues

Abstract P6-08-02: Comparative Analysis between Primary and Secondary in Breast Tumors by Polymorphysim of Androgen Receptor Gene and Mitochondria D-Loop Somatic Mutation

Abstract Background: It has not been fully understood how we can differentiate a new primary breast cancer from a recurrent tumor, when second tumor arises in ipsilateral breast after the surgery for primary breast cancer. To address this research question, we estimate the usefulness of a method analyzing polymorphism of androgen receptor gene and mitochondrial D-loop somatic mutation. Materials and methods: 1) Select patients: Among the 558 patients who received the breast conservative surgery in Tokai University Hospital (1991∼2004), 9 ipsilateral breast tumors and 11 contralateral breast tumors were submitted for the analysis. 2) Formalin-fixed paraffin-embedded (FFPE) sections of non-neoplastic lymph node were examined whether polymorphism of AR gene present or not. 3) When polymorphism of AR gene in non-neoplastic lymphoid tissue were demonstrated, ipsilateral and contralateral breast cancers were further examined. 4) When AR gene in breast cancers on same allele in primary and secondary tumors, FFPE sections were further analyzed by mutaion analysis of mitochondrial D-loop region. Results: 1) Polymorphism of AR was demonstrated in 8/9 (88.9%) and 9/11 (81.8%) non-neoplastic lymph nodes obtained from the patients who had ipsilateral and contralateral breast tumor, respectively. 2) Only 2 of 8 ipsilateral breast cancers demonstrated AR polymorphism different from primary cancer. In contrast, 6 of 9 contralateral breast cancers had different polymorphism for AR from primary breast cancers. 3) Analysis of mitochondrial D-loop mutation showed that 8 seconary ipsilateral cancers had different mutation in 3/8 (37.5%), identical mutation in 3/8 (37.5%), and no mutation in 2/8 (25.0%). Results of analysis for ipsilateral secondary breast cancers Conclusion: Half of the ipsilateral in breast secondary tumors were estimated as new primary lesions by molecular estimation. Combination analyses of AR gene polymorphism and mitochondrial D-loop somatic mutation unable us to distinguish between true recurrent or new primary cancers. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-08-02.

Is fascin really a useful marker in distinguishing between classical Hodgkin's lymphoma and various types of Non-Hodgkin's lymphomas in difficult cases?

BackgroundFascin is an actin cross-linking protein, which is part of the cytoskeleton and involved in cell motility in several cell types. The differentiation of epithelial cells is greatly influenced by...

Immunoexpression of Survivin in non-neoplastic lymphoid tissues and malignant lymphomas using a new monoclonal antibody reactive on paraffin sections

Survivin is a member of the inhibitor of apoptosis gene family, which is also implicated in mitosis regulation. Most reports in the literature impute poor prognosis to neoplasms with overexpression of this protein. The purpose of the present study is to validate and compare the immunohistochemical reactivity of malignant lymphomas and reactive lymphoid tissue using a new mouse monoclonal antibody to Survivin produced in our laboratory, 6-78. Survivin was detected by immunohistochemistry on tissue microarrays. It was shown that the antibody anti-Survivin 6-78 reliably stains formalin-fixed, paraffin-embedded reactive and neoplastic lymphoid tissues, mostly in a nuclear pattern. We confirmed using this novel antibody that Survivin immunostaining has a tendency to be lower in reactive lymphoid tissues and low-grade B cell lymphomas than in aggressive lymphomas. This antibody may represent a useful tool for standardizing the study of the immunoexpression of Survivin in neoplasms.

BAFF-R is Expressed on B-cell Lymphomas Depending on their Origin, and is Related to Proliferation Index of Nodal Diffuse Large B-cell Lymphomas

B-cell activating factor receptor (BAFF-R) is one of three known receptors for BAFF. BAFF-R is required for B-cell maturation and survival. We tried to determine the normal pattern of BAFF-R expression in non-neoplastic and neoplastic B- and T-cells. We used immunohistochemistry to evaluate the expression pattern of BAFF-R in non-neoplastic and neoplastic lymphoid tissues of routinely fixed paraffin-embedded samples, and examined the relationships among BAFF-R and expressions of CD10, bcl-6, MUM-1, and MIB-1. BAFF-R expression was detected on B-cells of the mantle zones, some cells within germinal centers, and scattered cells in the interfollicular areas of reactive lymph nodes. BAFF-R expression was only found in B-cell lymphoma (60/120, positive samples/examined samples), but not in T/NK cell lymphoma (0/10) or Hodgkin lymphoma (0/10). The proportions were as follows : follicular lymphoma (14/16), diffuse large B-cell lymphoma (DLBCL) (27/61), mantle cell lymphoma (4/4), and Burkitt lymphoma (0/4). According to Hans' criteria, DLBCLs were subclassified into germinal center B-cell-like (GCB) and non-germinal center B-cell-like (non-GCB) types. Interestingly, in nodal lymphomas, in the GCB subgroup (n=12), 9 of 12 (75%) were positive for BAFF-R, while 6 of 20 (30%) were positive in the non-GCB subgroup (n=20) (p < 0.05). In addition, expression of BAFF-R related to lower MIB-1 index was associated with GCB-type DLBCL. In conclusion, BAFF-R was only found in some B-cell lymphomas, which was closely associated with the expression pattern in normal counterparts, although BAFF-R expression on follicular lymphoma is different from that on germinal center cells, which is similar to bcl-2. BAFF-R was rather specifically related to low growth activity of GCB-type DLBCL of nodal origin.

The Reliability of Lymphoma Diagnosis in Small Tissue Samples Is Heavily Influenced by Lymphoma Subtype

A specific pathologic diagnosis is important in malignant lymphoma because the diverse disease subtypes require tailored approaches to clinical management. Reliance on small samples obtained with cutting needles has been advocated as a less invasive alternative to using larger, excised samples. Although published studies have demonstrated the safety and apparent sufficiency of this approach in informing clinical care, none have systematically determined the accuracy of pathologic lymphoma subtyping based on very small samples. We used a tissue microarray representing 67 cases of malignant lymphoma and 17 samples of nonneoplastic lymphoid tissue to model lymphoma diagnosis in small samples. Overall, 73.8% of the cases were diagnosed with a level of confidence deemed sufficient for directing clinical management; 85.9% of these diagnoses were accurate. Small cell lymphomas with highly distinctive immunophenotypes, including small lymphocytic, mantle cell, and T-lymphoblastic lymphoma, were recognized most consistently and accurately in the small samples. In contrast, follicular lymphoma and marginal zone lymphoma were especially difficult. Our results indicate that the reliability of lymphoma diagnoses based on small samples is heavily influenced by lymphoma subtype.

NPM-ALK–dependent expression of the transcription factor CCAAT/enhancer binding protein β in ALK-positive anaplastic large cell lymphoma

AbstractCCAAT/enhancer binding protein β (C/EBPβ) is one of a 6-member family of C/EBPs. These transcription factors are involved in the regulation of various aspects of cellular growth and differentiation. Although C/EBPβ has important functions in B- and T-cell differentiation, its expression has not been well studied in lymphoid tissues. We, therefore, analyzed its expression by immunohistochemistry and Western blot in normal lymphoid tissues and in 248 well-characterized lymphomas and lymphoma cell lines. Nonneoplastic lymphoid tissues and most B-cell, T-cell, and Hodgkin lymphomas lacked detectable levels of C/EBPβ. In contrast, most (40 of 45; 88%) cases of ALK-positive anaplastic large cell lymphoma (ALCL) strongly expressed C/EBPβ. Western blot analysis confirmed C/EBPβ expression in the ALK-positive ALCLs and demonstrated elevated levels of the LIP isoform, which has been associated with increased proliferation and aggressiveness in carcinomas. Transfection of Ba/F3 and 32D cells with NPM-ALK and a kinase-inhibitable modified NPM-ALK resulted in the induction of C/EBPβ and demonstrated dependence on NPM-ALK kinase activity. In conclusion, we report the constitutive expression of C/EBPβ in ALK-positive ALCL and show its relationship to NPM-ALK. We suggest that C/EBPβ is likely to play an important role in the pathogenesis and unique phenotype of this lymphoma.

Expression of retinoblastoma protein and P16 proteins in classic Hodgkin lymphoma: relationship with expression of p53 and presence of Epstein-Barr virus in the regulation of cell growth and death

Deregulation of several genes involved in cell cycle control has been reported in classic Hodgkin lymphoma (cHL). This study aimed to investigate the expression of tumor suppressor proteins (P16(INK4A), retinoblastoma protein, and p53) in cHL in relation to the proliferation and apoptosis of Hodgkin/Reed-Sternberg (H/RS) cells, correlating with the status of Epstein-Barr virus (EBV). A total of 66 cHL cases and 10 nonneoplastic reactive lymphoid tissues were retrieved from the archives. Immunohistochemistry technique was used for the detection of protein expression. Presence of EBV infection was detected by EBV early RNA in situ hybridization. p16(INK4A) gene deletion status was assessed by fluorescence in situ hybridization technique. Expression of P16(INK4A) was observed in 49.2% of the cases, whereas positive retinoblastoma protein and p53 expressions in the H/RS cells were detected in 89.1% and 81.5% of the cases, respectively. Epstein-Barr virus positivity was detected in 53.0% of the cases. Proliferation marker, Ki-67 expression, was observed in 86.7% of the cases. There was no significant correlation between the expression of the various tumor suppressor proteins and Ki-67. Retinoblastoma protein and p53 were also not associated with the presence of EBV. An inverse relationship was observed between the expression of P16(INK4A) and the presence of EBV. There were no significant homozygous or hemizygous deletions of the p16(INK4A) gene. However, an aberrant copy number of chromosome 9 with the loss of one or more p16(INK4A) loci was detected in all cases assessable by fluorescence in situ hybridization. Loss of function of one or more tumor suppressor proteins may be involved in defective cell regulation of H/RS cells. Epstein-Barr virus may have a role in inhibiting P16(INK4A) expression, thus resulting in a perturbed p16(INK4A)-Rb cell cycle checkpoint.

Checkpoint kinase 1 (CHK1) protein and mRNA expression is downregulated in aggressive variants of human lymphoid neoplasms

CHK1: gene encodes for a serine/threonine kinase involved in the regulation of cell cycle progression and DNA damage checkpoints. To determine the role of CHK1 in the pathogenesis of lymphoid neoplasms and its relationship to other DNA damage response genes, we have analyzed the gene status, protein, and mRNA expression in a series of tumors and nonneoplastic lymphoid tissues. CHK1 protein and mRNA expression levels were very low in both reactive tissues and resting lymphoid cells, whereas tumor samples showed a variable pattern of expression related to their proliferative activity. However, seven aggressive tumors showed a dissociate pattern of extremely low or negative protein expression in spite of a high proliferative activity. Four of these tumors were diffuse large B-cell lymphomas (DLCLs) with concordant reduced levels of mRNA, whereas one blastoid mantle cell lymphoma (B-MCL) and two DLCLs had relatively normal levels of mRNA. No gene mutations, deletions, or hypermethylation of the promoter region were detected in any of these cases. In all these tumors ATM, CHK2, and p53 genes were wild type. These findings suggest that CHK1 inactivation in NHLs occurs by loss of protein expression in a subset of aggressive variants alternatively to ATM, CHK2, and p53 alterations.

The EBV action in tonsils and adenoids

The bacteria involved in tonsil disease have been well studied, but we cannot say the same for the viruses. The method to detect virus make this approach difficult to study. Epstein–Barr Virus (EBV) infection usually occurs in early childhood and can persist in palatine and pharyngeal tonsil lymphocytes. EBV has been closely associated with the undifferentiated form of nasopharyngeal carcinoma (NPC) in its effect. Nevertheless, the presence of EBV in non-neoplastic lymphoid tissue of the nasopharynx and tonsil has rarely been investigated. Our objective was to study the frequency of EBV in tonsils and adenoids and to define the correlation between EBV and adenoid hyperplasia. In this study, we looked for EBV in adenoid and tonsil tissue of 165 patients (2 and 15 years old ) by in situ hybridization (ISH) for EBER 1/2 RNA. Resection of the adenoids was done for relief of upper respiratory tract obstruction, and the tonsils were resected because of recurrent tonsillitis and/or hyperplasia with upper airway obstruction. We divided the adenoid samples in two groups: one group 12–24 months old (average 18 months old) and the second group, 25 months to 15 years old. Tonsils were obtained from 85 patients, 3–13 years old (mean age 5.6 years) who underwent surgery due to recurrent tonsillitis or hyperplasia. EBV was demonstrated in lymphoid cells of 11 (34.3%) out of 32 adenoids for the first group and 36 (72%) out of 48 children of the second group. EBV was found in the respiratory epithelial cells of adenoid in one case. Children under 24 months of age can be infected by EBV, and this virus might be responsible for obstructive hyperplasia. Tonsils are less affected by EBV than the adenoids, suggesting that the EBV is more attracted to the adenoid tissue than the tonsillar tissue.

Epstein-Barr Virus (EBV) Subtypes and Variants in Malignant Tissue from Malaysian Patients

Epstein-Barr virus (EBV) is a ubiquitous virus that infects more than 90% of the world's population. In Malaysia this virus has been well documented in patients suffering from nasopharyngeal carcinoma, Hodgkin's lymphoma, and Burkitt's lymphoma. This study investigated the viral subtype and variant through the latent membrane protein-1 (LMP-1) gene taken from EBV-infected cancers in Malaysian patients. Nested polymerase chain reaction assays of EBV nuclear antigen-2 and single step polymerase chain reaction on the C-terminus of the LMP-1 gene were performed for virus typing and detection of a 30-bp deletion, respectively. Samples were obtained from 39 cases of nasopharyngeal carcinoma, 48 cases of Hodgkin's lymphoma, 19 cases of Burkitt's lymphoma and 19 cases of non-neoplastic reactive lymphoid tissues. All the tumors harbored EBV type A. Both the deleted and non-deleted variants were observed in the malignant tissues. In some cases, there was concurrent dual expression of both variants. Statistical analysis showed a significantly higher percentage of 30-bp deletions in cases of malignancies compared to reactive tissues. In conclusion, EBV type A predominates in Malaysian cancers, with a significant representation of the 30-bp deleted variant.

Diagnosis of B-Cell Lymphoma

To apply the polymerase chain reaction (PCR) to detect clonality for potentially helping to establish a definitive diagnosis of lymphoma in cytologic material. In this retrospective study, Papanicolaou-stained cytologic smears and formalin-fixed, paraffin-embedded tissues from 17 cases of B-cell lymphoma were examined to investigate their clonality by a PCR technique using three different approaches (FR3, FR3A and FR2) for amplification of immunoglobulin heavy chain genes. Cytologic smears from 10 cases of nonneoplastic lymphoid tissues and T-cell lymphomas served as negative controls. Monoclonality was detected in 9 of 17 cases (53%) of B-cell lymphoma in cytologic smears as compared with 8 of 16 cases (50%) in tissue sections. Semi-nested PCRs (FR3A/FR2) were superior to the single PCR (FR3) in the detection rate (41% vs. 18%). Five of seven cases (71%) of marginal zone B-cell lymphomas showed monoclonality, whereas only 4 of 10 cases (40%) of diffuse large B-cell lymphomas did so. Monoclonality was demonstrated in none of the negative controls. Clonality detection in B-cell lymphomas by PCR using cytologic smears is specific and equal in sensitivity to that using formalin-fixed, paraffin-embedded tissues. The detection rate is especially excellent in marginal zone B-cell lymphoma, in which the cytologic diagnosis is particularly challenging. Combined seminested PCRs for FR3A and FR2 are advocated for a reliable assessment of clonality.