Characterization of expression of protein kinase C isozymes in human B-cell lymphoma: Relationship between its expression and prognosis

Protein kinase C (PKC) enzymes play a major role in signal transduction and contribute to the regulation of cellular differentiation and proliferation. However, little is known about subtype-specific intracellular expression of PKC in human malignant lymphoma. To characterize the relationship between expression of PKC and B-cell lymphomas based on the different subspecies, we investigated the expression of four subspecies (alpha, beta II, gamma and delta) in five cases of reactive lymphoid tissues, 77 cases of human B-cell lymphoma and 17 human lymphoma cell lines. In the reactive lymphoid tissues, PKC beta II-positive cells were found in the mantle zones and marginal zones, and centroblasts and centrocytes in the germinal centers showed cytoplasmic staining with strong intensity against PKC delta. The present study is the first report to examine the expression of PKC delta in reactive lymphoid tissues. In interfollicular areas, a small number of T-cells were positive for PKC alpha. Protein kinase C gamma-positive cells were not found in these lymphoid tissues. Eight cases of Burkitt lymphoma (BL) (8/10; 80%) showed the overexpression of PKC alpha (P < 0.01), but other B-cell lymphoma cases except three cases of diffuse large B-cell lymphoma did not express PKC alpha. In addition, six and eight out of nine BL cell lines expressed the protein and mRNA of PKC alpha, respectively. These results indicate that PKC alpha was predominantly expressed on BL in comparison with other types of lymphoma. The expression of PKC gamma was observed in only five cases of BL. The overall survival of PKC gamma-positive BL was significantly better than that of PKC gamma-negative BL (P < 0.05). The expression of PKC gamma seems to be associated with a better prognosis in the limited number of BL cases in the present study.     

Preferential expression of the mucosal homing receptor integrin alpha 4 beta 7 in gastrointestinal non-Hodgkin's lymphomas.

Recent studies have identified the integrin alpha 4 beta 7 as a mucosal homing receptor that mediates lymphocyte migration to the intestinal mucosa by binding to MAdCAM-1, a vascular recognition molecule (addressin) selectively expressed on mucosal endothelium. In the present study, we have assessed the expression of alpha 4 beta 7 on B- and T-cell non-Hodgkin's lymphomas of different primary localization and on related normal lymphocytes. Among B-lineage lymphomas, expression of alpha 4 beta 7 was present in the majority of cases of malignant lymphomatous polyposis of the intestine and low-grade lymphoma of the mucosa-associated lymphoid tissue/monocytoid B-cell lymphoma and in some cases of precursor B-cell lymphoma. CLL/small lymphocytic lymphoma, (nodal) mantle cell lymphoma, follicular center cell lymphoma, Burkitt's lymphoma, and diffuse large B-cell lymphoma were virtually always alpha 4 beta 7 negative, as was the case when localized in the mucosa-associated lymphoid tissue. The normal B cells of the follicle mantles and part of the B cells of the extrafollicular B-cell compartment of lymphoid tissues expressed moderate levels of alpha 4 beta 7. By contrast, follicular center cells were alpha 4 beta 7 negative. Among T-lineage lymphomas, expression of alpha 4 beta 7 was also strongly related to the primary localization; in mucosal, nodal, and cutaneous T cell lymphomas the percentage of positive cases was 56%, 17%, and 0%, respectively. All cases of precursor T-cell lymphoma were alpha 4 beta 7 negative. High expression of alpha 4 beta 7 was found on a subset of peripheral blood memory T cells as well as on lymphocytes in the intestinal mucosa. We conclude that non-Hodgkin's lymphomas that are related to mucosa-associated B- and T-lymphocyte populations selectively express the mucosal homing receptor alpha 4 beta 7. The presence of this receptor underscores their distinctive character and may play an important role in determining their characteristic mucosal dissemination pattern.     

bcl-10蛋白异常表达对黏膜相关淋巴组织结外边缘区B细胞淋巴瘤的诊断价值

目的探讨bcl-10蛋白表达对黏膜相关淋巴组织结外边缘区B细胞淋巴瘤（MALT淋巴瘤）的诊断价值。方法收集140例不同部位的MALT淋巴瘤,包括胃38例、眼眶35例、肠16例、皮肤15例、涎腺15例、肺14例、甲状腺3例、其他部位4例。对照：10例扁桃体反应性滤泡增生（RFH）、5例眼眶的淋巴组织增生和143例非MALT淋巴瘤、不同类型的非霍奇金淋巴瘤（NHL）,包括20例NK／T细胞淋巴瘤、20例滤泡性淋巴瘤（FL）、20例间变性大细胞淋巴瘤（ALCL）、20例淋巴结内弥漫大B细胞淋巴瘤（DLBCL）、10例原发胃DLBCL、13例淋巴结边缘区淋巴瘤（NMZL）、12例套细胞淋巴瘤（MCL）、11例脾脏边缘区淋巴瘤（SMZL）、6例血管免疫母细胞性T细胞淋巴瘤（AITL）、6例外周T细胞淋巴瘤（PTCL）、3例B．小淋巴细胞淋巴瘤（B-SLL）、1例淋巴浆细胞性淋巴瘤（LPL）和1例浆细胞瘤。免疫组织化学EnVision法检测bcl-10蛋白;免疫组织化学双标记法检测CD20与bcl-10的共表达。结果在扁桃体RFH中,bel-10蛋白呈中等强度表达于生发中心B细胞质中,套细胞不表达,边缘区细胞和副皮质区T细胞呈弱表达。在眼眶淋巴组织增生中,2例bel-10阴性,3例主要呈淋巴滤泡生发中心B细胞质阳性,与扁桃体RFH的表达类似。在非MALT淋巴瘤的其他类型NHL中,除3例（3／10）原发胃DLBCL呈胞核阳性外,其余均未见胞核表达;在不同NHL中的胞质阳性分别为：结内（12／20）和胃（7／10）DLBCL、FL和ALCL（16／20）、PTCL（5／6）、AILT（6／6）、NMZL（13／13）、SMZL（11／11）、B-SLL（3／3）和浆细胞瘤（1／1）,11例MCL呈胞质可疑阳性,20例NK／T细胞淋巴瘤和1例LPL阴性;在部分淋巴瘤中可见肿瘤性细胞表达而反应性小淋巴细胞不表达：MALT淋巴瘤之bcl-10的总表达率为92．1％（129／140）,其中54．3％（76／140）胞质阳性,37．9％（53／140）胞核阳性;但不同部位之胞核阳性率有所不同。在MALT淋巴瘤中,bcl-10蛋白核强表达最常见于眼眶（25．7％,9／35）;除出现异常bcl-10胞核表达外,约20％有反应性滤泡的病例呈生发中心失表达。双标记显示bcl-10阳性细胞为CD20阳性细胞,但CD20阳性细胞多于bcl-10阳性细胞。结论（1）淋巴细胞增生性病变中bcl-10蛋白普遍表达,细胞质表达可出现在多数NHL和反应性增生中,但在淋巴瘤中呈肿瘤细胞表达而反应性细胞不表达,提示bcl-10异常可能与部分淋巴瘤的形成有关;（2）细胞核内bcl-10异常表达主要见于MALT淋巴瘤;眼眶、肺等部位的胞核强阳性和生发中心阴性的特殊模式,对MALT淋巴瘤的诊断及其与反应性病变的鉴别诊断有一定辅助意义。     

Expression of glucocorticoid receptors in non-neoplastic lymphoid follicles and B cell type malignant lymphomas

OBJECTIVE: To evaluate the expression of human glucocorticoid receptors (hGRs), such as hGR (4H2), hGR-alpha, and hGR-beta, in non-neoplastic lymphoid follicles and B cell type malignant lymphomas. METHODS: The expression of hGRs in non-neoplastic lymphoid follicles and malignant lymphomas, including diffuse large cell lymphoma, mantle cell lymphoma, and follicular lymphoma, was examined immunohistochemically. HGR (4H2) expression was confirmed by double immunostaining of tissues and in isolated cells from tonsillar germinal centres, and by immunoelectronmicroscopy. RESULTS: In secondary lymphoid follicles of any non-neoplastic diseases--such as chronic tonsillitis, reactive lymphadenitis, and Kimura's disease--the germinal centre cells often expressed hGR (4H2) and hGR-alpha. Double immunocytochemical staining of isolated germinal centre cells showed that the majority of hGR (4H2) positive cells were CD20 positive B cells, and that follicular dendritic cells also expressed hGR. Immunoelectronmicroscopy revealed the presence of nuclear hGR (4H2) in the binucleated follicular dendritic cells and germinal centre cells. The frequency of hGR (4H2) expression in diffuse large B cell lymphoma was higher, that in mantle cell lymphoma was lower, and that in follicular lymphoma was intermediate among the types of malignant lymphoma. The hGR (4H2) expression was less frequent in cases of grade I follicular lymphoma. CONCLUSIONS: There are differences in hGR expression between the germinal centre and the mantle zone in non-neoplastic lymphoid follicles, and differences of hGR (4H2) expression among the types of malignant lymphoma and grades of follicular lymphoma, which probably contribute to the different steroid sensitivities.     

Expression of the eukaryotic translation initiation factors 4E and 2alpha in non-Hodgkin's lymphomas.

Transition of cells from quiescence to proliferation requires an increase in the rate of protein synthesis, which is regulated in part by two key translation initiation factors, 4E and 2alpha. The expression and activity of both factors are increased transiently when normal resting cells are stimulated to proliferate. They are constitutively elevated in oncogene transformed cultured cells, and overexpression of either initiation factor in rodent cells makes them tumorigenic. In this study we investigate an association between the expression of translation initiation factors and lymphomagenesis. We have analyzed the expression of the protein synthesis initiation factors 4E and 2alpha by immunohistochemistry in reactive lymph nodes and several types of non-Hodgkin's lymphoma representing a wide range of clinical behaviors based on the Revised European-American Lymphoma behavioral classification. The study included 7 benign lymph nodes with follicular hyperplasia, 26 indolent lymphomas (6 marginal zone lymphomas, 7 small lymphocytic lymphomas, and 13 follicular lymphomas, grades 1 and 2), 16 moderately aggressive lymphomas (8 mantle cell lymphomas and 8 follicular lymphomas, grade 3), 24 aggressive lymphomas (14 large-B-cell lymphomas and 10 anaplastic large-cell lymphomas), and 15 highly aggressive lymphomas (7 lymphoblastic lymphomas and 8 Burkitt's lymphomas). Strong expression of initiation factors 4E and 2alpha was demonstrated in the germinal centers of reactive follicles. Minimal or no expression was seen in the mantle zones and surrounding paracortices, indicating that high expression of initiation factors 4E and 2alpha is associated with the active proliferation of lymphocytes. Most cases of aggressive and highly aggressive lymphomas showed strong expression of initiation factors 4E and 2alpha, in contrast to the cases of indolent and moderately aggressive lymphoma, in which their expression was intermediate between the germinal centers and the mantles of reactive follicles. A positive correlation was found between the expression of both initiation factors 4E and 2alpha and the Revised European-American Lymphoma behavior classification (P < 0.05). Thus, constitutively increased expression of initiation factors 4E and 2alpha may play an important role in the development of lymphomas and is correlated with their biological aggressiveness.     

caspase-3、bcl-2蛋白在非霍奇金淋巴瘤组织的表达及其与细胞凋亡和增殖的关系

目的探讨caspase-3、bcl-2蛋白在非霍奇金淋巴瘤(NHL)发生、发展中的可能作用及相互关系.方法应用TdT介导的dUTP缺口末端标记(TUNEL)技术和免疫组织化学链霉素抗生物素-过氧化酶(SP)法,检测5例反应性增生淋巴组织和119例NHL组织中的细胞凋亡和增殖细胞核抗原(PCNA)、caspase-3、bcl-2蛋白的表达水平.结果 caspase-3和bcl-2在119例NHL中表达的阳性率分别为86.6%(103例)和53.8%(64例).二者在良、恶性淋巴组织中的表达方式相反在反应性增生淋巴滤泡中心caspase-3高表达而bcl-2阴性表达,滤泡套区caspase-3阴性表达而bcl-2高表达;在肿瘤性滤泡中心bcl-2常高表达而caspase-3常表达减弱或不表达;在NHL中二者的表达与肿瘤恶性度呈相反关系,高度恶性组中caspase-3的表达(44.4%)高于低度恶性组(23.7%,P<0.01),而B细胞性淋巴瘤中bcl-2的表达(42.6%)低于低度恶性组(75.5%,P<0.01);caspase-3的表达与凋亡指数呈正相关(r=0.512, P <0.01)),bcl-2的表达与凋亡指数呈负相关(r=-0.436, P<0.01).此外,NHL的凋亡指数与增殖指数呈显著正相关(r=0.710, P<0.01).结论 caspase-3可能参与了NHL的凋亡调节机制.caspase-3和bcl-2蛋白在良、恶性淋巴组织中常呈现相反的表达方式,提示二者在淋巴细胞增殖动力学调节中可能存在着密切联系.     

Expression of lymphocyte homing receptors and vascular addressins in low-grade gastric B-cell lymphomas of mucosa-associated lymphoid tissue.

In this study, we examined lymphocyte homing receptor and vascular addressin expression in a case of primary gastric B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) with a secondary intestinal spread. We compared the findings with that observed in B cells of normal MALT and MALT acquired as a consequence of Helicobacter pylori-associated gastritis and other low-grade gastric B-cell MALT lymphomas. The neoplastic B cells in the gastric tumor were alpha 4 beta 7-, CD62L+, whereas the intestinal secondary was alpha 4 beta 7+, CD62L-. Incubation of isolated tumor cells from the stomach by H. pylori generated T-cell-dependent proliferation of neoplastic B cells and induced expression of alpha 4 beta 7 integrin similar to the intestinal tumor. These observations indicate that reversal of homing receptor profile in the gastric tumor by antigen specific stimulation may be responsible for secondary intestinal dissemination. In normal stomach and normal MALT, alpha 4 beta 7 and CD62L expression reflected the differentiation of the B cell. Plasma cells were alpha 4 beta 7+, CD62L-, whereas a subset of memory B cells were alpha 4 beta 7-, CD62L+. Homing receptor expression in MALT lymphoma B cells was heterogeneous, however, in line with their memory B-cell phenotype in the majority of cases, the neoplastic B cells were alpha 4 beta 7-, CD62L+. Neoplastic plasma cells were always alpha 4 beta 7+, CD62L-. The venules in normal gastric mucosa expressed mucosal addressin cell adhesion molecule-1 but not peripheral lymph node addressin. In normal MALT, H. pylori-associated follicular gastritis and MALT lymphomas high endothelial venules coexpressed mucosal addressin cell adhesion molecule-1 and peripheral lymph node addressin. These findings suggest expression of lymphocyte homing receptors by B cells and vascular addressins by mucosal venules are similar in normal MALT and MALT lymphomas, and factors controlling normal mucosal B-cell traffic are also operational in MALT lymphomas.     

CD40 expression in Hodgkin's disease.

CD40 is a transmembrane protein that belongs to a superfamily of proteins related to nerve growth factor receptor. CD40 is expressed on B cells and some B cell malignancies. It appears to be involved in B cell proliferation and the prevention of apoptosis in germinal center cells, which is accompanied by expression of bcl-2. Its expression is up-regulated by the EBV protein latent membrane protein-1 and cytokines interleukin-4 and interferon-gamma. The expression of CD40 in 37 cases of Hodgkin's disease and 23 cases of non-Hodgkin's lymphoma (11 T cell lymphomas and 12 B cell lymphomas) was examined by paraffin section immunohistochemistry using the BB-20 monoclonal antibody. In 26 of 37 cases of Hodgkin's disease the Reed-Sternberg cells showed strong membrane or cytoplasmic expression of CD40. Only 3 of 23 non-Hodgkin's lymphomas showed any expression of CD40 and then only weakly. There was no correlation between expression of bcl-2 or latent membrane protein-1 with CD40 expression. These results show that there is probable hyperexpression of CD40 in Hodgkin's disease and suggest that dysregulation of CD40 expression may play a role in the pathogenesis of Hodgkin's disease.     

Expression of angiogenic factors and hypoxia inducible factors HIF 1, HIF 2 and CA IX in non-Hodgkin's lymphoma

AIMS: Angiogenesis in solid tumour pathology is well established but less is known about its role in haematological malignancies. Our study investigated the immunohistochemical expression of a variety of angiogenic and hypoxic factors and microvessel densities on 110 cases of high- and low-grade non-Hodgkin's lymphomas and reactive lymphoid tissues. methods and results: Expression of vascular endothelial growth factor (VEGF) was present in 82 (96%) of the non-Hodgkin's cases and 35 (100%) of the reactive lymphoid tissue cases. Both hypoxia inducible factors 1 alpha and 2 alpha (HIF 1 alpha, 2 alpha) were weakly expressed in the majority of high- and low-grade lymphomas. Carbonic anhydrase IX (CA IX), a HIF-inducible membrane-bound enzyme, expression was not abundant with membranous staining being present in seven (8%) of the lymphoma cases and none of the reactive cases. Thymidine phosphorylase (TP) was distributed amongst macrophages and follicular dendritic cells but was not present in the neoplastic population. The vasculature was stained using CD34 which gave rise to a distinct vascular, predominantly paracortical network present in low-grade lymphomas and reactive lymphoid tissue but which was lost in high-grade lymphomas. CONCLUSION: Our results suggest that non-Hodgkin's lymphomas may be less angiogenic and hypoxically driven than most solid tumours, which has implications for possible future therapies.     

Fine-needle aspiration biopsy findings in marginal zone B cell lymphoma

Marginal zone B cell lymphomas (MZBCLs) represent a category of non-Hodgkin's lymphoma which may arise in a wide variety of extranodal organs where they are termed low grade B cell lymphomas of mucosa-associated lymphoid tissue (MALT). MZBCLs may involve primarily lymph nodes and or spleen where they are designated monocytoid B cell lymphoma or splenic marginal zone lymphoma, respectively. Recognition of this category of lymphoma, in particular, extranodal MALT lymphoma, is clinically significant in determining optimal therapy. Although there have been recent case reports describing the cytologic findings in low grade MALT lymphoma in various extranodal organs, this category of lymphoma has not been widely recognized or discussed in the cytology literature. The cytologic findings in seven fine-needle aspirations and two bronchial washings of histologically confirmed marginal zone lymphoma (five extranodal MALT lymphomas and four nodal marginal zone lymphomas) are described. In all of the cases, the cytologic specimens showed a polymorphous proliferation comprising a predominant population of intermediate sized lymphoid cells with centrocyte-like or monocytoid features, transformed cells, and variable numbers of plasma cells. These findings, while highly suggestive of MALT lymphoma in extranodal proliferations, may be more difficult to distinguish from reactive conditions in lymph nodes.     

CDK9/CYCLIN T1 expression during normal lymphoid differentiation and malignant transformation

CDK9 is a member of the CDC2-like family of kinases. Its cyclin partners are members of the CYCLIN T family (T1, T2a, and T2b) and CYCLIN K. The CDK9/CYCLIN T1 complex is very important in the differentiation programme of several cell types, controlling specific differentiation pathways. Limited data are available regarding the expression of CDK9/CYCLIN T1 in haematopoietic and lymphoid tissues. The aim of this study was to analyse the expression of the CDK9/CYCLIN T1 complex in lymphoid tissue, in order to assess its role in B- and T-cell differentiation and lymphomagenesis. CDK9/CYCLIN T1 expression was found by immunohistochemistry in precursor B and T cells. In peripheral lymphoid tissues, germinal centre cells and scattered B- and T-cell blasts in interfollicular areas expressed CDK9/CYCLIN T1, while mantle cells, plasma cells, and small resting T-lymphocytes displayed no expression of either molecule. CDK9/CYCLIN T1 expression therefore appears to be related to particular stages of lymphoid differentiation/activation. CDK9 and CYCLIN T1 were highly expressed in lymphomas derived from precursor B and T cells, from germinal centre cells, such as follicular lymphomas, and from activated T cells (ie anaplastic large cell lymphomas). Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma also showed strong nuclear staining. Diffuse large B-cell, Burkitt's lymphomas, and peripheral T-cell lymphomas, among T-cell lymphoproliferative disorders, showed a wide range of values. No expression of CDK9 or CYCLIN T1 was detected in mantle cell and marginal zone lymphomas. However, at the mRNA level, an imbalance in the CDK9/CYCLIN T1 ratio was found in follicular lymphoma and diffuse large B-cell lymphomas with germinal centre phenotype, and in the cell lines of classical Hodgkin's lymphomas, Burkitt's lymphomas, and anaplastic large cell lymphoma, in comparison with reactive lymph nodes. These results suggest that the CDK9/CYCLIN T1 complex may affect the activation and differentiation programme of lymphoid cells. The molecular mechanism through which the CDK9/CYCLIN T1 complex is altered in malignant transformation needs to be elucidated.     

Decreased expression of TGF-beta type 2 receptor in primary B-cell lymphomas of the stomach

TGF-beta insensitivity has been reported in some malignant lymphomas showing loss of TGF-beta receptor expression. This loss of TGF-beta sensitivity is thought to have removed the immunosuppressive properties of TGF-beta, thus enhancing cell proliferation and resulting in the development of malignant lymphoma. In this study, we performed immunohistochemical stains for TGF-beta1, TGF-beta RI and TGF-beta RII in primary gastric B-cell lymphomas in order to ascertain their possible roles in lymphomagenesis. A total of twenty cases of gastric lymphoma were included. All cases of low- and high-grade lymphomas were negative or weakly positive for TGF-beta1. Reactive lymphoid cells, including the germinal center, were also negative for TGF-beta1. In contrast, reactive germinal centers showed moderate to strong cytoplasmic or membranous staining for TGF-beta RI and TGF-beta RII. In malignant lymphomas, TGF-beta RI expression was maintained in all cases of low- and high-grade lymphomas. In contrast, TGF-beta RII expression was decreased in all low- and high-grade lymphoma cells. These findings suggest that the loss of TGF-beta RII expression may be involved in the lymphomagenesis of the stomach.     

Pathological and clinical study of the primary B and T cell lymphomas of intestines]

Thirty-one cases of primary non-Hodgkin's lymphoma of intestine were typed with monoclonal antibodies UCHL1, Ki-B5, L26 and Ki-MiP. Among them, there were 21 B cell lymphomas and 10 T cell lymphomas. Morphologically, the low-grade MALT lymphomas consisted of centrocyte-like cells, accompanying frequently with lymphoepithelial lesions and residual germinal centers, whereas the T cell lymphomas consisted of pleomorphic lymphoma cells, always accompanying with vascular infiltration, massive necrosis, atrophy of intestinal villi, phagocytosis of reactive histiocytes and epithelitropism. Clinically, T cell lymphomas of intestine occur more frequently in the young adults, usually with fever and diarrhea and is worse in prognosis than that of B cell lymphomas of the similar location.     

BIOMED-2聚合酶链反应Ig基因重排对成熟非霍奇金B细胞淋巴瘤诊断的价值

目的 探讨BIOMED-2聚合酶链反应(PCR)在成熟非霍奇金B细胞淋巴瘤(B-NHL)诊断中的价值.方法 收集成熟B-NHL组织标本72例,其中弥漫性大B细胞淋巴瘤37例,黏膜相关淋巴组织结外边缘区淋巴瘤35例为研究对象,并以反应性增生病变25例作为对照.提取以上组织的DNA,并以PCR来检测其完整性和可扩增性,选取质量合格的DNA.85.6%(83/97)的样品DNA长度>300 bp,其中60例成熟B-NHL和23例反应性增生可用于BIOMED-2 PCR检测免疫球蛋白重链(IgH)和kappa轻链(IgK)基因重排的克隆性.结果 利用BIOMED-2 PCR检测的60例成熟B-NHL中,57例存在Ig基因的克隆性重排,其检测敏感性为95%,23例反应性增生病例中未出现Ig基因的克隆性重排,其检测特异性为100%.结论 BIOMED-2 PCR适用于石蜡包埋组织.该方法具有很高的敏感性和特异性,对成熟B-NHL诊断的辅助价值很高.     

Heterogeneity of protein kinase C beta(2) expression in lymphoid malignancies

AIMS: Protein kinase C (PKC) beta is an important regulator of lymphoid survival and its expression has been shown to be altered in lymphomas. The aim was to determine the expression of PKC beta(2) in various subtypes of lymphoproliferative diseases by immunohistochemistry. METHODS AND RESULTS: One hundred and forty archival samples representing various subtypes of lymphoproliferative diseases were analysed. Certain subtypes, such as mantle cell, lymphocytic or follicular lymphoma, were found to express PKC beta(2) in > 90% of the samples. In follicular lymphomas, the follicular lymphomatous areas were constantly labelled, whereas residual germinal centres remained negative. In follicular hyperplasia, PKC beta(2)+ cells were found in the mantle and marginal zones. Most angioimmunoblastic T-cell lymphomas, lymphoblastic T-cell lymphomas and marginal zone/mucosa-associated lymphoid tissue (MALT) lymphomas were labelled with anti-PKC betaII antibody, but the pattern of expression was more heterogeneous in these subtypes. A minority of diffuse large B-cell lymphomas were stained and most plasma cell malignancies were negative. None of the cases of Hodgkin's disease and anaplastic large cell lymphoma expressed PKC beta(2). CONCLUSIONS: PKC beta(2) expression varies significantly among lymphoproliferative diseases. In our series, the highest level of expression was found in mantle cell lymphomas and chronic lymphocytic lymphoma.     

IMP-3 is differentially expressed in normal and neoplastic lymphoid tissue

IMP-3 is a member of the insulin-like growth factor II mRNA binding protein (IMP) family of proteins that play a role in RNA trafficking and stabilization and cell growth and migration during embryogenesis but which are down-regulated in adult tissue. However, IMP-3 has recently been shown to be overexpressed in several epithelial malignancies, with increased expression correlating with aggressive behavior. To our knowledge, there is no published literature evaluating IMP-3 in lymphoid tissue. Accordingly, we immunohistochemically evaluated IMP-3 expression in normal lymphoid tissue and 141 lymphoid neoplasms. Physiologically, IMP-3 expression was restricted to germinal center B cells. Among lymphoid neoplasms, Hodgkin lymphoma demonstrated the highest percentage of positive cases (26/26, 100%) often with bright staining. Burkitt lymphoma was positive in 10 (83%) of 12 cases with moderate to bright staining. Although follicular lymphoma was also positive in a high percentage of cases (12/15, 80%), the intensity was exclusively weak to moderate. Although 22 (85%) of 26 of diffuse large B-cell lymphomas were positive for IMP-3, there was wide variability in staining intensity, which did not correlate with classification into activated B cell versus germinal center B origin. By contrast, lower proportions (8%-20%) of other non–germinal center B lymphoma subtypes were IMP-3–positive. In conclusion, although IMP-3 expression is seemingly restricted to physiologic germinal center B cells, its expression in lymphomas of germinal center B origin is less robust. However, there does appear to be some association with the latter group of lymphomas, which may prove to have diagnostic or therapeutic relevance as the biologic role of IMP-3 is further elucidated.     

Flow cytometric analysis of immunoglobulin heavy chain expression in B-cell lymphoma and reactive lymphoid hyperplasia

The diagnosis of B-cell lymphoma (BCL) is often dependent on the detection of clonal immunoglobulin (Ig) light chain expression. In some BCLs, the determination of clonality based on Ig light chain restriction may be difficult. The aim of our study was to assess the utility of flow cytometric analysis of surface Ig heavy chain (HC) expression in lymphoid tissues in distinguishing lymphoid hyperplasias from BCLs, and also differentiating various BCL subtypes. HC expression on B-cells varied among different types of hyperplasias. In follicular hyperplasia, IgM and IgD expression was high in mantle cells while germinal center cells showed poor HC expression. In other hyperplasias, B cell compartments were blurred but generally showed high IgD and IgM expression. Compared to hyperplasias, BCLs varied in IgM expression. Small lymphocytic lymphomas had lower IgM expression than mantle cell lymphomas. Of importance, IgD expression was significantly lower in BCLs than in hyperplasias, a finding that can be useful in differentiating lymphoma from reactive processes.     

Expression of TCL1 in hematologic disorders.

OBJECTIVE: TCL1, MTCP1 and TCL1b are three members of a new family of oncogenes that are expressed in T cell leukemias of ataxia telangiectasia patients (T-PLL, T-CLL). TCL1 is located at 14q32.1 and activated by juxtaposition to the alpha/delta-locus at 14q11 or beta-locus at 7q35 of the T cell receptor during the reciprocal translocations t(14;14)(q11;q32), t(7;14)(q35;q32), or inversion inv(14)(q11;q32). TCL1 encodes a predominantly cytoplasmic protein of 114 aa (14 kD) of unknown function. Recent studies suggest that TCL1 promotes cell survival rather than stimulating cell proliferation, as previously proposed. METHODS: In an attempt to clarify the contexts in which TCL1 is expressed, we investigated TCL1 expression in 114 lymphoma and leukemia patients by Northern blot, RT-PCR and immunohistochemistry. RESULTS: TCL1 expression is restricted to lymphoid cells, and is found in neoplastic (T and B cell neoplasms, and Hodgkin's disease) and nonneoplastic proliferations (reactive lesions). Out of 114 cases, 18 neoplasms of myeloid and 4 cases of epithelial origin were TCL1-negative. In lesions of the lymphoid system, both low- and high-grade lymphomas were found to express TCL1. CONCLUSIONS: We propose that TCL1 expression especially in high-grade B cell non-Hodgkin's lymphomas might interfere with B cell differentiation and promote the transition from low- to high-grade lymphoma.     

Immunologic methods in cytology: definitive diagnosis of non-Hodgkin's lymphomas using immunologic markers for T- and B-cells

The cytologic diagnosis of malignant lymphoma can be extremely difficult because the cytologic features of the malignant cells in small cell and mixed small and large cell lymphomas may be indistinguishable from those of reactive lymphoid cells. In addition, large cell lymphoma can be difficult to distinguish from undifferentiated carcinoma in cytologic specimens. Using the avidin-biotin immunoperoxidase technic and antibodies to the B-cell markers alpha, gamma, and mu heavy chains and kappa and lambda light chains, to the T-cell markers Leu-1, Leu-2a, and Leu-3a, to the lymphoid marker T200, to TdT, and to Leu-M3, the authors studied 35 cytologic specimens including pleural, cerebrospinal, and ascites fluids and fine-needle aspirations. Immunologic staining allowed them to make a definitive diagnosis of lymphoma or reactive effusion in every case studied and resulted in a significant modification of the morphologic diagnosis in over 50% of cases. In 16 cases the lymphoid cells were monoclonal B-cells: ten expressing IgM kappa; four expressing IgM lambda; one expressing IgA kappa; and one expressing kappa without demonstrable heavy chain expression. Although there are no good markers of monoclonality for T-cells, the authors were able to make a positive diagnosis in two cases of T-cell lymphoid malignancies by the expression of an aberrant phenotype on the malignant cells. The expression of TdT confirmed the diagnosis in one case of common ALL and one lymphoblastic lymphoma. In a patient with a "null cell" large cell lymphoma, the expression of T200 on the malignant cells ruled out the possibility of carcinoma. In 15 cases the marker studies indicated a reactive lymphoid proliferation. The authors conclude that immunologic markers are very useful in the cytologic diagnosis of lymphoma.