Differential cytokine expression in EBV positive peripheral T cell lymphomas.

AIM: To investigate whether specific cytokines are secreted locally at the tumour site in Epstein-Barr virus (EBV) positive peripheral T cell lymphoma (PTCL). METHODS: An RNase protection assay system was used to study the differential expression of 21 cytokines in parallel in eight cases of EBV positive non-nasal PTCL, and compared with 11 EBV negative non-nasal PTCLs and three EBV positive nasal natural killer (NK) cell lymphomas. RESULTS: Among the eight EBV positive cases, interferon gamma (IFN-gamma), lymphotoxin beta (LT beta), interleukin 10 (IL-10), tumour necrosis factor alpha (TNF-alpha), transforming growth factor beta 1 (TGF-beta 1), and IL-1 receptor a (IL-Ra) were frequently detectable. IL-15, IL-6, IL-4, IL-1 beta, TNF-beta, and IL-9 were sporadically detectable. Of the frequently detectable cytokines, IFN-gamma and LT beta were commonly detected in the EBV negative cases. For cases with > 50% EBV encoded small non-polyadenylated RNA (EBER) positive cells, IL-10, TNF-alpha, and TGF-beta 1 were detected in three of three cases, and IL-1Ra in two of three cases. For cases with < 20% EBER positive cells, IL-10 was detected in three of five cases, TNF-alpha in two of four cases, but TGF-beta 1 and IL-1Ra were not detected. Interestingly, IL-6 was detected in two of three cases with > 50% EBER positive cells, but only in one of five cases with < 20% EBER positive cells. For comparison, in NK cell lymphomas, IL-10, TNF-alpha, IL-1Ra, and IL-6 were all detectable, but TGF-beta 1 was not detected at all. Immunohistochemical staining revealed IL-10 in many cells; in contrast, EBV latent membrane protein 1 (LMP1) was only found to be positive in isolated cells. CONCLUSIONS: Certain cytokines, such as IL-10 and TNF-alpha, might be expressed preferentially in EBV positive peripheral T cell lymphomas. It is likely that such a cytokine environment enhances EBV infection and contributes towards tumorigenesis.     

Epstein–Barr virus infection, drug resistance and prognosis in Korean T- and NK-cell lymphomas

T-cell lymphomas are a biologically heterogeneous group of diseases with varying clinical presentations and outcomes. We tried to understand the effect of Epstein-Barr virus (EBV) on lymphogenesis, prognostic factors and drug resistance of T-cell lymphomas, and to establish their relationship with international prognostic factors. Formalin-fixed paraffin-embedded tissue sections from 35 patients (12 women and 23 men) with T-cell lymphomas were examined to detect the presence of EBV using RNA in situ hybridization for EBV-encoded small nuclear RNA (EBER) 1/2 and immunohistochemical stain for latent membrane protein (LMP)-1. We also tried to establish the expression of p53 and P-glycoprotein (P-gp) using immunohistochemistry. The distribution according to the subgroup was: two T-lymphoblastic lymphomas, 13 NK/T-cell lymphomas, one angioimmunoblastic T-cell lymphoma, 17 peripheral T-cell lymphomas, unspecified, and two anaplastic large cell lymphomas. The EBER was detected in 15 of 35 T-cell lymphomas (42.9%) and among these it was detected in five of 17 nodal lymphomas (29.4%) and 10 of 18 extranodal lymphomas (55.6%). There was close correlation between EBER positivity and NK/T-cell lymphoma (P = 0.032). Expression of LMP was found in a proportion of tumor cells in seven of the 15 EBER-positive cases (46.7%). There was no correlation between EBER expression and complete response (CR rate), but coexpression of EBER and p53 was associated with treatment failure (P = 0.047). The 18 patients (51.4%) with p53 expression had significantly poorer outcomes compared with the 17 patients without p53 expression (CR rate, P < 0.0005; overall survival, P = 0.0102). Twenty of 35 patients (57.1%) were positive for P-gp expression. P-gp expression was significantly associated with treatment failure (P = 0.001) and overall survival (P = 0.0089). Seventeen of 35 patients (48.6%) treated with systemic chemotherapy or radiation therapy achieved a CR after initial treatment. When the prognostic factors were grouped using the international prognostic index, the CR rate was 58.8% for the low risk group, 50.0% for the low-intermediate risk group, 14.3% for the high-intermediate risk group, and 0% for the high risk group. In conclusion, high incidence of EBV was detected among Korean patients with T-cell lymphomas. Our study supports the prediction that patients who express p53 and P-gp have a poorer prognosis than those who do not and this should be considered when treatment strategies for individual patients are selected.     

Pathologic characteristics of primary cutaneous T-cell lymphoma in Korea.

Cutaneous T-cell lymphomas (CTCL) represent a heterogeneous group of peripheral T-cell lymphomas arising in the skin and show considerable variations in clinicopathological features. This study was designed to examine viral genomes and cellular proliferation markers in CTCLs arising in Korea. On the basis of their morphologic characteristics and immunophenotypes, 43 cases of primary CTCL were classified, and evaluated for association with either HTLV-I or EBV, p53 protein immunoreactivity and Ki-67 labeling index (LI). EBV was demonstrated in 15 cases (35%) either by EBER in-situ hybridization or PCR; particularly high rates were exhibited by angiocentric T-cell lymphomas. PCR was used to detect HTLV-I proviral DNA, but none was found. The p53 expression rate was higher in large cell lesions, but the Ki-67 LI failed to show any significant differences among the different types. We therefore concluded that in Korea, HTLV-I is less frequently associated with CTCL than in other endemic countries. EBV was found particularly in angiocentric lesions, regardless of cell size or degree of pleomorphism. Because of its high positive rates in high grade lesions, the p53 expression showed positive correlation with histologic grade; however, the Ki-67 labeling index did not correlate with the histologic grade in CTCL.     

Prevalence of EBV RNA in sinonasal and Waldeyer's ring lymphomas.

A high incidence of a T cell phenotype of sinonasal lymphomas in other Asian countries has been associated with a high incidence of Epstein Barr virus (EBV) infection. We analyzed 13 sinonasal and 18 Waldeyer''s ring lymphomas for the prevalence of EBV encoded RNA (EBER) using a sensitive and specific in situ hybridization. In addition, we examined the relationship of histologic findings and immunophenotype as well as the location of the lymphomas to the presence of EBV. The EBER was detected in each of 12 sinonasal lymphomas with a T cell immunophenotype. One B cell sinonasal lymphoma was EBER negative. Four of 18 Waldeyer''s ring lymphomas were positive for EBER, including two T cell lymphomas. Two of 16 B cell Waldeyer''s ring lymphomas were EBER positive. Morphologically, 11 of 20 diffuse large cell lymphomas, 2 diffuse mixed small and large cell lymphomas, 2 of 4 immunoblastic lymphomas and 1 lymphoplasmacytic lymphoma were EBER positive. Four follicular large cell lymphomas were EBER negative. A characteristic angiocentric or angiodestructive pattern was found in most T cell lymphomas and EBER positive cases. These findings indicate that EBV infection is more strongly associated with the T cell immunophenotype, angiocentric pattern and sinonasal location of the lymphoma.     

EBV in situ hybridization study for non-Hodgkin's lymphomas.

Epstein-Barr virus(EBV) has been implicated in the pathogenesis of B-lymphoproliferative disorders, T-cell lymphomas and Hodgkin''s disease. In this report, we performed an in situ hybridization study on EBV genome in 10 cases of nasal non-Hodgkin''s lymphoma(NHL), 20 cases of Waldeyer''s ring(WR) NHL, and 20 cases of nodal NHLs to document EBV association with lymphomas in Koreans. For immunophenotyping, monoclonal antibodies for CD 20, MB 2, CD 45Ro & CD 43 were used. For in situ hybridization study, EBV DNA probe for Bam HI ''V'' fragment and EBV RNA probe for EBER and BHLF were used. Twenty two cases(44%) of malignant lymphomas were positive for EBV genome. Generally, T-cell lymphomas showed a higher positive rate(61%) than B-cell lymphomas(24%). Among T-cell lymphomas, nasal lymphomas showed a higher positive rate(80%) than WR(50%) or nodal lymphomas(50%). Of 22 EBV genome positive cases, 10 cases were positive for EBER, 10 cases for BHLF, and 2 cases for both EBER and BHLF. The histologic types by Working Formulation(WF) were not correlated with EBV genome positive rate, whereas lymphomas showing the histologic spectrum of polymorphic reticulosis(PR) showed a higher positive rate(65%) than lymphomas without PR-like features(40%). These results indicate that nasal T-cell lymphomas with the histologic spectrum of PR are strongly associated with EBV and that the anatomic site may be an important factor in this association.     

Differential cytokine expression in EBV positive peripheral T cell lymphomas.

AIM: To investigate whether specific cytokines are secreted locally at the tumour site in Epstein-Barr virus (EBV) positive peripheral T cell lymphoma (PTCL). METHODS: An RNase protection assay system was used to study the differential expression of 21 cytokines in parallel in eight cases of EBV positive non-nasal PTCL, and compared with 11 EBV negative non-nasal PTCLs and three EBV positive nasal natural killer (NK) cell lymphomas. RESULTS: Among the eight EBV positive cases, interferon gamma (IFN-gamma), lymphotoxin beta (LT beta), interleukin 10 (IL-10), tumour necrosis factor alpha (TNF-alpha), transforming growth factor beta 1 (TGF-beta 1), and IL-1 receptor a (IL-Ra) were frequently detectable. IL-15, IL-6, IL-4, IL-1 beta, TNF-beta, and IL-9 were sporadically detectable. Of the frequently detectable cytokines, IFN-gamma and LT beta were commonly detected in the EBV negative cases. For cases with > 50% EBV encoded small non-polyadenylated RNA (EBER) positive cells, IL-10, TNF-alpha, and TGF-beta 1 were detected in three of three cases, and IL-1Ra in two of three cases. For cases with < 20% EBER positive cells, IL-10 was detected in three of five cases, TNF-alpha in two of four cases, but TGF-beta 1 and IL-1Ra were not detected. Interestingly, IL-6 was detected in two of three cases with > 50% EBER positive cells, but only in one of five cases with < 20% EBER positive cells. For comparison, in NK cell lymphomas, IL-10, TNF-alpha, IL-1Ra, and IL-6 were all detectable, but TGF-beta 1 was not detected at all. Immunohistochemical staining revealed IL-10 in many cells; in contrast, EBV latent membrane protein 1 (LMP1) was only found to be positive in isolated cells. CONCLUSIONS: Certain cytokines, such as IL-10 and TNF-alpha, might be expressed preferentially in EBV positive peripheral T cell lymphomas. It is likely that such a cytokine environment enhances EBV infection and contributes towards tumorigenesis.     

肠道T细胞淋巴瘤中的EB病毒感染和T细胞内抗原1的表达

目的 探讨ＥＢ病毒感染在肠道Ｔ细胞淋巴瘤发病中的意义。方法 用ＥＢＥＲ１／２原位杂交及三步ＡＢＣ法免疫组织化学染色技术,观察２４例肠道Ｔ淋巴瘤患者中ＥＢ病毒感染及Ｑ细胞内抗原（ＴＩＡ－１）抗原表达情况,选用的抗体有ＴＬＡ－１,ＬＭＰ－１,ＣＤ３,ＣＤ２０,ＣＤ３０和ＣＤ４５ＲＯ等。     

Therapeutic outcome of Epstein-Barr virus positive T/NK cell lymphoma in the upper aerodigestive tract

Expression of the natural killer (NK) cell antigen CD56 is uncommon in malignant lymphoma, but when it is, it is almost exclusively of the non-B cell lineage and show a preference for the nasal and nasopharyngeal region. T/NK cell lymphoma is known to be aggressive and refractory to treatment. It is highly associated with the Epstein-Barr Virus (EBV), but clinical investigations are rarely reported, that is until recently. We report here, on the clinical features and therapeutic outcomes of patients with T/NK cell lymphomas and its association with EBV. We reviewed fifty-four cases with peripheral T cell lymphomas in the upper aerodigestive tract between Jan. 1987 and Aug. 1998 from the Severance Hospital, Yonsei University College of Medicine. The diagnosis of T/NK cell lymphoma was made according to the expression of the NK cell markers, CD56 antigen and cytoplasmic CD3epsilon, in tumor specimens, by immunohistochemistry. Epstein-Barr early region (EBER) RNA was detected using in situ hybridization on paraffin-embedded sections. Among the 54 cases with malignant lymphomas occurring in the upper aerodigestive tract, 20 had T/NK cell lymphoma (37%). The primary sites of T/NK cell lymphomas were the nasal cavity, 12 cases (60%), the tonsils, 4 cases (20%), the nasopharynx, 2 cases (10%), and the oropharynx, 2 case (10%). There were no differences between the features, at diagnosis or therapeutic modalities for patients with T/NK cell lymphoma and non-T/NK cell lymphoma. The complete remission rate of T/NK cell lymphomas was lower than non-T/NK cell lymphomas (65% vs 85%, p=0.02). The overall survival of T/NK cell lymphomas was 13 months (1-74 month), which was significantly lower than non-T/NK cell lymphomas [60.6% with a median follow up of 22 months (1-101 month, p=0.02)]. Disease free survival of T/NK cell lymphomas was 22 months (4-66 month), significantly lower than non-T/NK cell lymphomas [73.8% with a median follow up of 22 months (2-95 month), p=0.04]. The overall survival rates for T/NK cell lymphomas were significantly lower than for EBV positive non-T/NK cell lymphomas (p=0.018). EBER RNA was detected in the paraffin-embedded tissue sections of all T/NK cell lymphomas, compared to only 17.6% (6 of 34 cases) for non- T/NK cell lymphomas. In conclusion, as patients with T/NK cell lymphomas showed poor clinical outcomes, and a high association with EBV positivity, clinical trials with more investigational therapeutic strategies, and further research into the relationship of EBV infection with pathogenesis of T/NK cell lymphoma is warranted.     

High frequency of Epstein–Barr virus in Chinese peripheral T-cell lymphoma

Forty-two cases of Chinese T-cell lymphoma were studied for expression of Epstein–Barr virus (EBV) encoded RNA (EBER-1) and EBV latent membrane protein-1 (LMP-1) using in situ hybridization and immunohistochemistry, respectively. EBV was detected in tumour cells in 24/39 peripheral T-cell lymphomas (62%), comprising 18/27 pleomorphic, medium and large cell lymphomas (67%), 4/6 angioimmunoblastic lymphadenopathy-like lymphomas (67%), 2/2 Lennert's lymphomas, 0/2 anaplastic large cell lymphomas, and 0/2 T-zone lymphomas. EBV was not found in three T-lymphoblastic lymphomas. EBV was associated with 12/24 nodal (50%) compared with 12/15 extranodal (80%) peripheral T-cell lymphomas. In EBV positive nodal lymphomas, 9/12 cases (75%) contained less than 10% EBER positive tumour cells. In EBV positive extranodal lymphomas, 9/11 cases (82%) showed EBV gene expression in more than 50% of the tumour cells, and in five of these almost all tumour cells were positive. Lymphomas of the nasopharynx (mainly midline granuloma-type) showed EBER-1 expression in nearly all tumour cells. LMP-1 was detected in 19/23 EBER positive peripheral T-cell lymphomas (83%). Our results show that EBV is strongly associated with peripheral T-cell lymphomas in Chinese. An important role for the virus is suggested in lymphomas of the nasopharynx. The significance of EBV in T-cell lymphomas that contain only a minor population of virally infected tumour cells is currently unclear.     

Histological and immunophenotypic profile of nasal NK/T cell lymphomas from Peru: high prevalence of p53 overexpression.

Nasal NK/T-cell lymphoma is a unique form of lymphoma highly associated with Epstein-Barr virus (EBV). These lymphomas are rare in Western populations and much more prevalent in some Asian and Latin American countries. Although there are several sizable studies from Asian countries, the same is not true from South America. The aim of this study was to analyze a series of 32 cases of nasal T-cell lymphoma from Peru and to further extend the characterization of this disease. Immunohistochemistry was performed on paraffin sections using the following antibodies: CD20 (L26), CD45RO, CD3, Ki67, CD57, CD56, TIA-1, bcl-2, and p53. The presence of EBV was investigated with immunohistochemical analysis for latent membrane protein (LMP)-1 and in situ hybridization using an antisense riboprobe to EBER 1. The 32 patients included 18 men and 14 women (M:F ratio, 1.2:1), with a median age of 43 years (11 to 72). Three categories were identified: (1) Nasal NK/T cell lymphomas (28 cases): The morphology ranged from small or medium-sized cells to large transformed cells. Necrosis was present in 86% of the cases, and angioinvasion was seen in 36% of the cases. All cases were positive for CD45RO, CD3, and for TIA-1. CD56 was positive in 21 of 27 cases (78%), and CD57 was negative in all cases. EBER 1 positivity was identified in most of the tumor cells in 27 of 28 cases (96%), including the six cases in which CD56 was negative. Overexpression of p53 was detected in 24 cases (86%). (2) Blastic NK cell lymphoma (1 case): The neoplastic cells resembled those of lymphoblastic lymphoma. CD56 and CD45RO were positive; TIA-1, TdT, and EBER-1 were negative. (3) Peripheral T-cell lymphoma (PTCL) unspecified (3 cases): CD56, TIA-1, and EBER-1 were negative. Nasal lymphomas from Peru with a T cell phenotype are predominantly EBV-associated NK/T cell lymphomas, similar to those described in Asian countries. The expression of CD56, TIA-1, and EBER-1, in combination, are very useful markers for the diagnosis of nasal NK/T cell lymphoma in paraffin-embedded tissue. The differential diagnosis of T-cell lymphomas in the nasal region should include rare cases of PTCL unspecified and the blastic variant of NK cell lymphoma. P53 is overexpressed in 86% of the cases. The significance of this finding with regard to clinical behavior and prognosis remains to be determined.     

Lymphomas in patients with connective tissue disease. Comparison of p53 protein expression and latent EBV infection in patients immunosuppressed and not immunosuppressed with methotrexate

Cell cycle dysregulation as measured by p53 protein expression and latent Epstein-Barr (EBV) infection are important in the pathogenesis of lymphoma, particularly in immunosuppressed patients. Although latent EBV commonly is detected in lymphomas arising in patients with connective tissue disease who are immunosuppressed with methotrexate, p53 protein expression has not been reported. We compared the immunohistologic expression of p53 protein and the incidence of latent EBV infection in lymphomas arising in patients with connective tissue disease treated and not treated with methotrexate. Increased p53 staining was detected in 10 of 11 lymphomas arising in patients after methotrexate therapy vs 5 of 11 in patients not treated with methotrexate. Latent EBV was detected in 7 of 13 lymphomas arising in patients after methotrexate therapy vs 2 of 11 in patients not treated with methotrexate. Concordant p53 expression and latent EBV were detected in 5 of 7 lymphomas arising after treatment with methotrexate, including 1 that regressed after methotrexate therapy was withdrawn. These findings suggest that cell cycle dysregulation and EBV-related transformation are important in the pathogenesis of lymphomas arising in patients with connective tissue disease who are immunosuppressed with methotrexate.     

Distribution and ZAP-70 expression of WHO lymphoma categories in Shanxi, China: a review of 447 cases using a tissue microarray technique.

This study aims to assess the distribution of lymphoma subtypes in Shanxi, China, according to the World Health Organization (WHO) classification, and to compare the relative distribution with other areas of the world. H&E-stained tissue sections from the archives of the Shanxi Tumor Hospital, China, were reviewed and 447 cases with sufficient materials were selected for detailed study. A panel of antibodies and probes was assembled, including antibodies to ALK1, bcl-6, CDs 1alpha, 3, 4, 5, 7, 8, 10, 15, 20, 23, 30, 43, 56, 68, 79alpha, and 99, cyclin D1, EMA, kappa, lambda, LMP1, PAX5, TdT, Vs38C and ZAP70, plus EBER RNA probe by in situ hybridization. The 447 lymphoma cases, subtyped according to the WHO classification, were assembled in triplicate into 11 tissue microarrays and examined with the panel of markers described. Among the 447 cases, 385 (82.6%) were confirmed to be non-Hodgkin lymphomas (NHL) and 62 (13.9%) were Hodgkin lymphomas of classic type (CHL). Of the NHL cases, 68.6% were B-cell lymphomas and 30.6% T/NK-cell lymphomas. Histiocytic neoplasms accounted for only three cases (0.8%). Diffuse large B-cell lymphomas (DLBCL) were the most common subtype (35.1%), followed by peripheral T-cell lymphomas unspecified (PTun, 12.0%), extranodal marginal zone B-cell lymphomas (MALT lymphomas, 11.7%), follicular lymphomas (FL, 8.6%), T-lymphoblastic lymphomas (T-LBL, 7.0%), anaplastic large cell lymphomas (ALCL, 4.2%), B small lymphocytic lymphomas (B SLL, 3.6%), and mantle cell lymphomas (MCL, 2.6%). Of 263 B-cell neoplasms, 105 (39.9%) expressed immunoglobulin light chain, including 52 kappa and 53 lambda, detectable in paraffin sections. The incidence of DLBCL was similar to many Western countries and Asia. The frequency of FL was, however, much lower than the usual pattern in Western countries, although NK/T-cell lymphomas were more common (30.6%), similar to other countries in Asia, including Japan and Korea. With regard to markers of EBV infection, 8 of 385 (2.1%) NHL cases gave positive findings by both in situ hybridization (EBER RNA) and immunohistochemistry (LMP-1), whereas 24 (6.2%) expressed only the EBER and 12 (3.1%) expressed only LMP-1. EBV positivity was found in 24 of 119 (20.2%) T and NK cell lymphomas, in 20 of 263 (7.6%) B cell neoplasms, and in 37 of 62 (59.7%) CHLs. In CHLs there was complete concordance of results by both in situ hybridization (EBER RNA) and immunohistochemistry (LMP-1) procedures. ZAP70 was detected in most T cell-lineage disorders (61.4%) and also in a subset of B small lymphocytic lymphomas (50%). However, ZAP-70 was expressed in a minority of other types of B-cell lymphomas, including precursor B-cell acute lymphoblastic leukemia (25%), diffuse large B-cell lymphoma (26.7%), follicular lymphoma (15.2%), and lymphoplasmacytic lymphoma (9.1%). Immunohistochemical analysis represents an effective method for assessing ZAP-70 expression and reveals that a variety of B-cell malignant neoplasms express ZAP-70, albeit at low frequency.     

HLA antigen expression in enteropathy associated T cell lymphoma.

AIMS: To investigate the occurrence of abnormal patterns of HLA-ABC and HLA-DR expression in enteropathy associated T cell lymphoma and to relate such abnormalities to the Epstein Barr virus (EBV) status of the tumours. METHODS: Eleven enteropathy associated T cell lymphomas were immunostained with HC10 (HLA-ABC heavy chain) and TAL 1B5 (HLA-DR alpha chain) monoclonal antibodies and polyclonal anti-beta 2 microglobulin (beta 2m, the HLA-ABC light chain) antibodies. In situ hybridisation for EBV using EBER probes was performed on all cases. RESULTS: Tumour cells of two of 11 patients were EBER positive. One of these showed partial, and the other, complete loss of beta 2m. HLA-DR expression was undetectable in both patients. Of the remaining nine EBER negative tumours, two were HLA-ABC heavy chain negative or showed only occasional positive cells and five of nine showed partial or complete loss of the HLA-ABC light chain, beta 2m. Seven of the nine cases were either negative for HLA-DR or showed weak expression in a proportion of tumour cells. CONCLUSIONS: These data show that low or absent HLA-ABC and HLA-DR antigen expression occurs commonly in enteropathy associated T cell lymphoma. These abnormal patterns of HLA expression may be associated with escape from immune attack which, in a minority of patients, could be directed against EBV antigens.     

Prevalence of Epstein-Barr virus in non-Hodgkin's lymphomas in central region of Tunisia

The purpose of this study was to evaluate the prevalence of EBV in non-Hodgkin's lymphomas occuring in non-immunocopromised patients in Tunisia through a series of 126 cases. EBV was investigated by EBER oligonucleotide in situ hybridization (ISH) and LMP1-immunohistochemistry. Serological study of EBV has been performed before therapy in 28 patients. EBV was detected in tumor cells by ISH in 28/126 (22.2%) cases. Variable proportions of tumor cells were positive. LMP1 was identified in only 8 cases. EBV was more frequently observed in T-cell lymphomas (9/24 patients; 37.5%) than in B-cell lymphomas (19/102 patients; 18.6%) (p=0.04). There was a strong relationship between EBV and small intestine lymphomas (6/8 patients; 75%) and T/NK nasal type lymphomas (3/3 patients; 100%). EBV serological reactivation was noted in 7/13 patients in clinical stages III/IV and in only 1/10 patients in stages I/II (p=0.03). In conclusion, the prevalence of EBV in Tunisian non-Hodgkin's lymphomas is low but variable depending on the histological type and anatomical location with a predilection for small intestine and nasal lymphomas.     

Analysis of chromosomal copy number changes and oncoprotein expression in primary central nervous system lymphomas: frequent loss of chromosome arm 6q

Primary central nervous system lymphoma (PCNSL) is a rare disease. A small number of cytogenetic studies of PCNSL have been conducted and several reports have been published on associated molecular and protein expression data. We combined these approaches in a series of eight PCNSL cases, analyzing the chromosomal abnormalities using comparative genomic hybridization (CGH), testing for Epstein Barr virus (EBV) involvement by in situ hybridization for EBER, assessing expression of p53, Bcl-2, Bcl-6 and CD10 by means of immunohistochemistry, and screening for mutations of the TP53 gene by DGGE. TP53 gene mutations and EBV expression were not detected. Most of the cases showed p53, Bcl-6 and Bcl-2 protein expression. CGH revealed DNA copy number changes in all eight cases. The most frequent changes were gains of chromosome 12 (63%), chromosome 18 (50%) and 20q (38%), and loss of chromosome arm 6q (75%). No correlation between protein expression and chromosomal abnormalities was found in these eight cases. Although gains of chromosome 12, 18 and 20q and loss of 6q have also been reported in systemic diffuse large B-cell lymphomas, the frequency of 6q deletion is clearly higher in PCNSL. This creates a similarity to primary lymphomas of the testes that also frequently have deletions of 6q. This suggests that suppressor genes located on chromosome 6q may play a role in the development of lymphomas at immunoprivileged sites, like the CNS.     

Lymphomas of the oral cavity: histology, immunologic type, and incidence of Epstein-Barr virus infection

The purpose of this study was to determine the histologic class and immunologic phenotype of lymphomas presenting initially in the oral cavity and whether this correlated to a high incidence of Epstein-Barr virus (EBV) infection as has been reported with lymphomas in the nasal cavity. Seventy-one cases of oral lymphomas from the oral pathology referral service were analyzed retrospectively. They were classified according to the Revised European American Lymphoma (REAL) classification system using routine immunohistochemistry. EBV infection was determined by detection of early viral RNA sequences (EBER) and latent membrane protein (LMP-1) expression. Only non-Hodgkin's lymphomas were observed, with a female predominance of 2:1. They were primarily of B-cell origin and histologically classified mainly as large B-cell type (68%); T-cell lymphomas were rare (8%). EBV infection was observed in 14% of the B-cell lymphomas, an incidence rate higher than that reported in studies of B-cell lymphomas not located in the oral cavity but not as high as that observed in pleomorphic T-cell lymphomas (all sites, 36%) or nasal cavity T-cell lymphomas (nearly 100%). Interestingly, EBV proliferation did not correlate with expression of either Bcl-2 or p53.     

不同亚型T细胞淋巴瘤与EB病毒的关系

目的 :探讨不同组织学类型T细胞淋巴瘤 (TCL)与EBV感染的关系。方法 :对 83例 (6种类型 )TCL进行研究 ,包括低度恶性 30例 (其中小多形 2 1例、小淋巴细胞性 9例 ) ,高度恶性 5 3例 (其中大 /中多形 31例、淋巴母细胞性 9例、间变性大细胞性 7例、透明细胞性 6例 )。采用PCR检测EBV特征性的DNA序列 (EBV DNA)和ISH法检测EBV编码的RNA(EBER 1/2 )。结果 :每种类型TCL均有EBV的阳性表达 ,低度恶性组与高度恶性组之间EBER 1/ 2表达率差别有显著性 (P <0 0 5 )。结论 :各种类型TCL的发生发展均与EBV感染有关 ,但高度恶性组EBER 1/ 2的表达比低度恶性组更显著。     

Proliferation and apoptosis in primary gastric B-cell non-Hodgkin's lymphoma

To elucidate the role of cell turnover in primary gastric B-cell non-Hodgkin's lymphomas we studied tissue samples of 72 patients—26 small cell (25 MALT lymphomas) and 46 large cell (31 MALT lymphomas). Proliferation indices and apoptotic indices were measured by Mib-1 expression and terminal deoxynucleotidyl-transferase (TdT)-mediated nick end labelling, respectively. Furthermore, expression of the apoptosis related gene-products bcl-2 and p53 was studied. Large cell lymphomas showed significantly higher proliferation indices (59.1% vs. 15.4%) and apoptotic indices (3.2% vs. 0.7%) than small cell lymphomas. Proliferation and apoptotic indices were positively correlated ( r =0.371, P =0.03). Expression of the bcl-2 protein was significantly higher in the small cell lymphomas. Furthermore, cases with a high bcl-2 expression showed both a significantly decreased proliferation ( P <0.0001) and apoptotic index ( P =0.0096) compared to bcl-2 negative cases. Expression of the mutant p53 protein was present in 8.0% of small cell and in 18.2% of large cell lymphomas. p53 positive cases showed significantly higher proliferation indices, but showed no correlation with apoptotic index. These data suggest that impaired apoptosis by bcl-2 may be more prominent than proliferation in the genesis of small cell lymphomas, whereas a high cell turnover characterizes large cell primary gastric lymphomas.     

TCL1 expression and Epstein-Barr virus status in pediatric Burkitt lymphoma

Elevated T-cell leukemia-1 (TCL1) oncoprotein expression might promote human Burkitt lymphoma (BL) because increased TCL1 causes Burkitt-like lymphomas in TCL1 transgenic mice. Epstein-Barr virus (EBV) infection has been implicated as a cause of increased TCL1 expression in multiple BL cell lines, suggesting a critical connection between EBV and TCL1-induced BL. The TCL1 expression and EBV status of 14 sporadic pediatric BL cases was determined by immunohistochemical staining for TCL1 and in situ hybridization for EBV-encoded RNA (EBER). Our results showed TCL1 protein in 11 cases, predominantly in the nucleus with strong-intensity staining. EBER was positive in 4 cases, with 3 of these cases also TCL1+. In the 10 cases that were EBER-, TCL1 was strongly positive in 8. These data indicate that the TCL1 oncoprotein is expressed strongly in most pediatric BL cases. However, persistent EBV is not essential for increased TCL1 expression, although elevated TCL1 and c-MYC coexpression might cooperate in the development of most pediatric and adult BL cases.