Non-HTLV-1-associated primary gastric T-cell lymphomas show cytotoxic activity: clinicopathological, immunohistochemical characteristics and TIA-1 expression in 31 cases.

AIMS: Most primary gastrointestinal lymphomas are of B-cell origin and T-cell origin is very rare. Recent studies have suggested that human T-cell lymphotrophic virus type 1 (HTLV-1) may be involved in the development of primary gastric T-cell lymphoma. We analysed 31 patients with primary gastric T-cell lymphoma in south-west Japan, an area endemic for HTLV-1, and determined their phenotypes, genotypes, and HTLV-1 status. METHODS AND RESULTS: Here we present 31 cases of primary gastric T-cell lymphoma in a HTLV-1-endemic area in Japan and analyse the clinical status, histology, phenotype and virus status. The median age at onset of primary gastric T-cell lymphoma was 57 years with a gender ratio of M:F = 1.58:1. Six of the 31 primary gastric T-cell lymphoma cases had HTLV-1 proviral DNA (five males, one female), nine of the 31 cases were positive for anti-adult T cell leukaemia antibody, without examination of HTLV-1 proviral DNA (five males, four females), eight were non-HTLV-1-associated primary gastric T-cell lymphoma (four males, four females) and the other eight cases were unknown. Primary gastric T-cell lymphoma usually presented as a large ulcerated tumour at the corpus to the antrum and histologically consisted of anaplastic large cell type (n = 2), pleomorphic large cell type (n = 3), pleomorphic medium and large cell type (n = 14), pleomorphic medium cell type (n = 11), and angioimmunoblastic T-cell lymphoma type (n = 1). There were no clear macroscopic and microscopic differences between HTLV-1-associated and non-HTLV-1-associated primary gastric T-cell lymphoma. Most patients died within 2 years of diagnosis, and both types of primary gastric T-cell lymphoma (with and without HTLV-1) were associated with poor prognosis. Cytotoxic marker analysis showed that HTLV-1-associated lymphomas were negative for TIA-1, while non-HTLV-1-associated lymphomas were positive for TIA-1. CONCLUSIONS: Our results suggest that in HTLV-1-endemic areas, patients with HTLV-1-associated primary gastric T-cell lymphoma should be managed carefully and that TIA-1 seems to be useful for identifying the aetiology of this lesion.

Accessory cell tumour: a clinicopathological study of 16 aggressive tumours containing EBV-positive Hodgkin and Reed-Sternberg-like giant cells.

AIMS: Lymph nodes contain non-lymphoid accessory cells including follicular dendritic cells and interdigitating dendritic cells. Functionally, these cells belong to the category of immune accessory cells involved in antigen presentation to B or T-lymphocytes. Neoplastic proliferation of these cells is very uncommon. We present here the clinicopathological features of 16 cases of accessory cell tumour. METHODS AND RESULTS: We performed electron microscopic and immunohistochemical examinations, and used in-situ hybridization for EBV-encoded RNA (ISH-EBV) to detect the EBV genome in 11 cases, and Southern blot analysis to assess EBV clonality in two cases. Tumour cells were composed of oval-to-spindle cells arranged in diffuse, vague storiform, fascicular and sometimes whorled patterns in a background of small lymphocytes. In all cases, binucleated or multinucleated Hodgkin and Reed-Sternberg-like giant cells were encountered. Staining for CD68 was positive in all cases. CD21, CD35, Ki-M4p, Ki-FDC1p, and S100 exhibited variable reactivity. ISH-EBV yielded positive labelling in seven of 11 cases, of which five exhibited EBV only in Hodgkin and Reed-Sternberg-like giant cells. Southern blot analysis showed clonality of EBV terminal repeats (EBV-TR) in the two cases examined. Electron microscopic examination showed that many of the tumour cells had numerous interwoven long villous cell processes connected by occasional desmosomes. Many tumours were very refractory to chemotherapy and radiation, with a few exceptions, and half of the cases classified initially as stage IV. A short survival time, of 10 months or less, was observed in seven of 16 patients. CONCLUSIONS: Our study identified more aggressive behaviour of accessory cell tumours. Our results suggest that EBV may potentially induce activation of accessory cells to form Hodgkin and Reed-Sternberg-like giant cells, which correspond with poor prognosis.

Analysis of the immunoglobulin heavy chain gene variable region of intravascular large B-cell lymphoma.

Intravascular large B-cell lymphoma (IVLBL) is a rare neoplasm characterized by proliferation of lymphoma cells within the blood vessels. The cell origin of IVLBL has not yet been determined. We examined cell lineage, with immunohistochemical staining and molecular analysis, using polymerase chain reaction (PCR) of the variable region of the immunoglobulin heavy chain (Ig-VH) gene. We also investigated the cell origin using direct sequence analysis of the complementary-determining region 2 (CDR2) and framework region 3 (FR3) in six cases, consisting of two male and four female patients. The sequences in five cases showed frequent mutations. The percent homology to their closest germline genes ranged from 74.7 to 91.8%. However, one case showed a percent homology of 99.4% in CDR2 and FR3 of Ig-VH. All cases showed rearrangements of VH3 family genes. Interestingly, three of the IVLBL cases with hypermutated IgH genes showed the expression of CD5. Therefore, expression of CD5 in lymphoma cells does not indicate that the origin of IVLBL is the same as mantle cell lymphoma having the character of CD5 expression, which develops in pre-germinal center cells. Our results indicate that most IVLBLs may originate in the post-germinal center cells, based on the presence of somatic mutation in VH genes, although some heterogeneous cases are intermingled within IVLBL.

CD10 and Bcl10 expression in diffuse large B-cell lymphoma: CD10 is a marker of improved prognosis.

AIMS: Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically and pathologically heterogeneous. The Bcl10 gene was recently isolated from the breakpoint region of t(1;14)(p22;q32) in mucosa-associated lymphoid tissue (MALT) lymphomas, and is considered to be an apoptosis-associated gene. CD10 is considered to be a marker of follicular centre B-cell differentiation. To assess the clinical significance and roles of CD10 and Bcl10 in DLBCL, we analysed 138 cases, using immunohistochemical methods. METHODS AND RESULTS: CD10 expression was limited to the cytoplasm, whereas Bcl10 expression was detected in the cytoplasm and/or nuclei. CD10 expression was detected in 39 of 138 cases (28.2%), cytoplasmic Bcl10 in 68 cases (49.2%), and nuclear Bcl10 in 34 cases (24.6%). Nuclear Bcl10 was detected in 14 of 28 cases (50%) of extranodal DLBCL, but only 20 of 110 cases (18.2%) of nodal DLBCL. Cytoplasmic Bcl10 was detected in 19 of 28 cases (67.8%) of extranodal DLBCL and 49 of 110 cases (44.5%) of nodal DLBCL. CD10 expression closely correlated with improved survival (68% overall survival (OS) vs. 48% OS), but not with site of disease. A high International Prognostic Index (IPI) was considered to be a poor prognostic factor associated with a shorter OS. CD10 expression was detected in 27 of 84 cases (32.1%) with low-risk IPIs, and in 12 of 54 cases (22.2%) with high-risk IPIs. In the low-risk group, cases expressing CD10 carried a better prognosis than CD10- cases (93% OS vs. 71% OS), whereas this was not the case in the high-risk group (25% vs. 20%). CONCLUSIONS: Bcl10 expression was associated with extranodal DLBCL, but not with prognosis. CD10 expression was closely associated with improved survival, but not with risk as predicted by IPI. Overall, our results suggest that CD10 expression may be useful, in combination with clinical parameters, for determining the prognosis of DLBCL.

Expression of human tumor-associated antigen RCAS1 in Reed-Sternberg cells in association with Epstein-Barr virus infection: a potential mechanism of immune evasion.

RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is present in neoplastic cells, induces apoptosis of natural killer (NK)/T cells and plays a role in immune evasion. Fas ligand (FasL) is considered to have similar roles. The Epstein-Barr virus (EBV)-encoded latent membrane protein is expressed by malignant Hodgkin and Reed-Sternberg (H&RS) cells of EBV-associated Hodgkin's disease (HD) and considered to be a target of cytotoxic T lymphocytes (CTLs). However, CTL response is inadequate in HD. To determine whether RCAS1 and FasL are expressed in EBV-associated HD and participate in immune evasion, tissues of 20 EBV(-) and 15 EBV(+) HD cases were immunohistochemically stained for RCAS1, FasL and HLA classes I and II, whose deficiencies could explain CTL escape. Lymphocytes surrounding H&RS cells tended to be CD4(+) cells and rarely CD8(+), TIA-1(+) (cytotoxic marker) or NK cells. HLA class I and/or II were expressed in all EBV(+) HD cases, and RCAS1-expressing H&RS cells were found in 14/15 (93%) EBV(+) HD cases but only 8/20 (40%) EBV(-) HD cases (p < 0.05). FasL was detected in 9/15 (60%) and 7/20 (35%) EBV(+) and EBV(-) HD cases, respectively. ssDNA-positive (apoptotic) lymphocytes, surrounding H&RS cells, were rarely seen but were present in RCAS1(+) cases (20/22 cases, 91%) rather than negative cases (0/13 cases, 0%) (p < 0.005). Our findings suggest that EBV(+) H&RS cells might evade the host immune response by expressing RCAS1 rather than FasL.

Expression of hnRNP B1 in four major histological types of lung cancers.

Heterogeneous nuclear ribonucleoprotein B1 is one of the nuclear pre-mRNA binding proteins involved in RNA metabolism. Recently, over-expression of B1 has been reported to be useful in the early detection of squamous cell carcinomas of the lung. To elucidate its significance in other histological types of lung cancers, we carried out a comparative study, four major types of lung cancers and normal lung tissues. 37 surgical specimens were examined using a B1-specific monoclonal antibody (2B2). Immunohistochemically, 2B2 demonstrated B1 protein in the nuclei not only of squamous cell carcinoma (10/10) but also of adenocarcinoma (17/18), small cell carcinoma (5/5) and large cell carcinoma (3/4). A lesser amount of B1 protein was also detected in normal cells. Quantitative immunoblotting revealed that B1 expression was markedly higher in cancer tissues than normal tissues and it varied among the four histological types. To establish the usefulness of B1, a threshold should be set for over-expression.

Chromosome 16q deletion and loss of E-cadherin expression in Hodgkin and Reed-Sternberg cells.

Hodgkin and Reed-Sternberg (H&RS) cells are generally considered to be the neoplastic cells of Hodgkin's disease (HD); however, such H&RS cells are a few in number due to the numerous reactive cells. Very few data have so far been published on the cytogenetic abnormalities in HD. We have previously used the analysis of comparative genomic hybridization (CGH), employing sorted H&RS cells. The most commonly observed genetic aberrations were a loss on 16q11/21, a gain on 1p13 and a gain on 7q35/36. To confirm the loss of 16q, we analyzed the loss of heterozygosity (LOH) using the regions D16S3075 (16p13), D16S3068 (16q11), D16S3136 (16q12), D16S503 (16q13), D16S515 (16q21), D16S3091 (16q23) and D16S520 (16q24). A total of 100 sorted H&RS cells were compared with a similar number of sorted reactive T cells in 15 cases with HD, including 5 cases with nodular sclerosis (NS) type and 10 cases with mixed cellularity (MC) type. LOHs of 16q, especially 16q21-23, were frequently detected, but 16p deletions were infrequent. Analysis of 16q21 showed LOH in 12 of 15 cases with HD (80%), including 9 cases with MC type (90%) and 3 cases with NS type (60%). 16q23 showed LOH in 9 of 15 cases with HD (60%), including 5 cases with MC type (50%) and 4 cases with NS (80%). On the other hand, 16p13 showed LOH in 3 of 15 cases with HD (20%). Immunohistochemical staining showed that H&RS cells rarely expressed E-cadherin, which is located on 16q. Our findings suggest that 16q deletion, especially 16q21-23, is probably involved in H&RS giant cell formation and tumorigenesis.

Possible immortalization of Hodgkin and Reed-Sternberg cells: telomerase expression, lengthening of telomere, and inhibition of apoptosis by NF-kappaB expression.

Telomerase, an enzyme associated with cellular immortality, is expressed on malignant tumor cells. Deregulation of telomerase is thought to facilitate tumorigenesis and cellular immortality by providing cancer cells with unlimited proliferation capacity. Hodgkin and Reed-Sternberg (H&RS) cells are generally considered as neoplastic cells in Hodgkin's disease (HD), however, such cells are only found in a minority of HD lesions. In addition, H&RS cells with mitotic features are rare and mummified forms are occasionally encountered. There are no available data on the relationship between telomerase activity and apoptosis in HD. We studied 14 cases with Hodgkin's disease (mixed cellularity type, nine cases; nodular sclerosis type, five cases) to clarify the relationship between telomerase activity and apoptosis using in situ hybridization of human telomerase reverse transcriptase (hTERT), reverse transcriptase-polymerase chain reaction (RT-PCR) of hTERT, using extracted RNA and immunohistochemistry of nuclear factor-?B (NF-?B), and TdT-mediated dUTP-digoxigenin nick end-labeling (TUNEL) technique for apoptosis. We also analyzed the telomere length, using sorted H&RS cells. TUNEL showed a few apoptotic H&RS cells, but the cells frequently expressed hTERT, as confirmed by ISH and RT-PCR. Lengthening of the telomere of H&RS cells was noted in ten cases. In addition, H&RS cells frequently expressed NF-?B, which is known as an inducible transcription factor and inhibitor of apoptosis. Our findings of telomerase activity in H&RS cells indicate that these cells are neoplastic and are potentially immortal. In addition, NF-?B expression on H&RS cells suggests its possibility in inhibition of apoptosis of these cells.

Amplification and expression of a decoy receptor for fas ligand (DcR3) in virus (EBV or HTLV-I) associated lymphomas.

The recently identified decoy receptor 3 (DcR3) binds to FasL and inhibits FasL-induced apoptosis, and is considered to play a role in the immune escape system of neoplastic cells. To examine the involvement of DcR3 in the immune evasions of virus-associated lymphoma, we analyzed the amplification and expression of DcR3, using dot blot and in situ hybridization (ISH), in 45 cases, which included 17 cases with Epstein-Barr virus (EBV)-associated lymphoma (seven pyothorax-associated B-cell lymphomas (PAL); ten natural killer lymphoma (NKL)), seven cases with adult T-cell leukemia lymphoma (ATLL), 13 Hodgkin's disease (eight EBV-associated cases; five non-EBV-associated cases), and eight control cases (three reactive lymphadenopathy; five non-EBV-associated-B-cell lymphoma). EBV-associated PAL and NKL exhibited DcR3 amplification and expression in lymphoma cells. ATLL also showed DcR3 expression and amplification. The cases with DcR3 amplification showed DcR3 expression; however, the expression was confined in the neoplastic cells, but not in the reactive cells. In Hodgkin's disease (HD), DcR3 was expressed only in Hodgkin and Reed-Sternberg giant (H-RS) cells. However, DcR3 was not expressed or amplified in reactive lymphadenopathy. Non-EBV-associated B-cell lymphoma also rarely expressed DcR3, and showed no amplification except in two cases, in which rare expression was present. Our results suggest that EBV and HTLV-I probably use DcR3 to escape from the immune system during lymphomagenesis, or virus-infected lymphoma cells with DcR3 expression might be selected in the multistep tumorigenesis.

Follicular dendritic cell sarcoma: ultrastructural and immunohistochemical studies.

A rare case of follicular dendritic cell (FDC) sarcoma is reported. A 71-year-old woman was admitted for evaluation of constipation. Computerized tomography showed cervical, supraclavicular, retroperitoneal, and paraaortic lymphadenopathies. Histological findings from a cervical lymph node revealed Hodgkin's disease at first. But tumors that arose both in the cervical and the left interscapular regions during the chemotherapy were immunohistochemically confirmed to be of follicular dendritic cell origin. The ultrastructural findings were consistent with those of FDC sarcoma. FDC sarcoma is a rare nonlymphoid cell-derived malignant tumor originating from the lymphoid tissue. The diagnosis of FDC sarcoma is most accurately established by immunohistochemical methods, using its specific markers.

Gastrointestinal T cell lymphoma: predominant cytotoxic phenotypes, including alpha/beta, gamma/delta T cell and natural killer cells.

Gastrointestinal T cell lymphoma (TCL) is a rare subset of peripheral TCL, presenting with or without cytotoxic phenotype, a history of coeliac disease (CD) and enteropathy. However, CD is rare in Japan. Here, we describe the clinicopathological features of 18 Japanese cases. Lesions were found in the small intestine (n=13), stomach (n=3) and colon (n=2). Seven patients presented with enteropathy but none had a history of CD. Lymphomas appeared as ulceration (n=11), tumour formation (n=6), or polypoid growth (n=1). Histologically (REAL classification), neoplastic lesions were composed of intestinal type T cell lymphoma (ITCL, n=13, including one case with NK type), anaplastic large cell (ALCL, n=2), adult T cell leukaemia/lymphoma (ATLL, n=2), and lymphoblastic type (n=1). Epstein Barr virus infection was detected by EBER-1 in situ hybridization in 6 of 11 cases with ITCL but not in the other types. ALCL expressed CD30. CD56 was expressed in 3 of 11 cases of ITCL but not in other types. Among the 10 examined cases, 8 were alphabeta T cell type [CD2+, CD3+, T cell receptor (TCR)delta-1-, betaF1+], one was gammadelta T cell type [CD2+, CD3+, TCRdelta-1+, betaF1-], and the remaining case expressed natural killer (NK) cell type [CD2+, CD3-, CD56+, TCRdelta-1-, betaF1-]. Among the 8 examined cases, 3 expressed CD103 molecule, which was associated with extrathymic T cells of intraepithelial lymphocytes. All cases except ATLL expressed the cytotoxicity-associated molecule of TIA-1, and 11 of 14 TIA-1 positive cases expressed activated cytotoxic molecules of perforin, granzyme B, and/or Fas ligand. Despite the morphological, genetic and phenotypic heterogeneity, prognosis was poor, and 11 of 13 patients with small intestinal lesions died albeit appropriate treatment, but 3 of 4 patients with gastric or colonic lesions were still alive. The main cause of death was intestinal perforation. The latter might be due to the site specificity of small intestine and tumour cytotoxicity.

Mutation analysis of mitotic checkpoint genes (hBUB1 and hBUBR1) and microsatellite instability in adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a neoplasm of T-lymphocytes, and human T-cell lymphotropic virus type-I (HTLV-I) is etiologically considered as the causative virus of ATLL. The karyotypes of ATLL are very complex in both number and structure, although no specific karyotype abnormalities have been identified. HTLV-I is thought to integrate its provirus into random sites in host chromosomal DNA and induces chromosomal instability. The BUB gene is a component of the mitotic checkpoint in budding yeast. Recently, human homologues of the BUB were identified and mutant alleles of hBUB1 and hBUBR1 were detected in two colorectal tumor cell lines, which showed microsatellite instability (MIN). In vitro, BUB proteins form a complex of monomers. These proteins interact with the human MAD1 gene product, a target of the HTLV-1 tax oncogene. We examined the role of checkpoint gene in the chromosomal abnormalities of ATLL by investigating mutations of hBUB1 and hBUBR1, and MIN of replication errors of BAX, insulin-like growth factor, and transforming growth factor beta type II. We analyzed ten cases with ATLL and eight B-cell lymphomas (five diffuse large cell lymphomas, three follicular lymphomas). Complex chromosomal abnormalities were detected in ATLL, while B-cell lymphomas showed only simple or minimal chromosomal abnormalities. Significant mutations/deletion of hBUB1 or hBUBR1 were detected in four of ten cases with ATLL, including two heterozygous point mutations, one homozygous point mutation, and one with a 47 bp deletion. In contrast, only one of eight B-cell lymphomas showed nonsense mutation of hBUBR1. None of the ATLL and B-cell lymphomas showed MIN. In the multistage process of leukemogenesis of ATLL, our findings indicate that mutations of mitotic checkpoint genes may play an important role in the induction of complex chromosomal abnormalities.

Hepatosplenic gammadelta T-cell lymphoma: relation to Epstein-Barr virus and activated cytotoxic molecules.

AIMS: Hepatosplenic gammadelta T-cell lymphoma (TCL) is a rare, aggressive subset of peripheral TCL that presents with hepatosplenomegaly and cytopenia. Epstein-Barr virus (EBV) infection and activated cytotoxic molecules (granzyme and perforin) are uncommon in hepatosplenic gammadelta CTL. EBV infection and activated cytotoxic molecules are occasionally detected in non-hepatosplenic gammadelta TCL. We describe the clinicopathological features of three Japanese cases who were not immunodeficient. METHODS AND RESULTS: All cases showed gammadelta T-cell type (CD2+, CD3+, T-cell receptor (TCR)delta-1+, betaF1-). Two cases expressed natural killer (NK) cell-associated antigens (CD8-, CD16+, CD56+; CD8-, CD16-, CD56+), and one expressed CD8 (CD8+, CD16-, CD56-). All cases expressed cytotoxicity-associated molecules (perforin, granzyme B, TIA-1 and Fas ligand). However, perforin and Fas ligand were not detected in one case. In-situ hybridization analysis with EBER probes revealed strong nuclear positivity in all neoplastic cells. In addition, two cases showed clonal bands of the EBV terminal repeat (TR) gene. Cytologically, instead of the presence of monomorphic medium-sized cells, our three cases showed pleomorphic medium-sized and large cells. CONCLUSIONS: Our gammadelta TCL cases were clinicopathologically considered to be compatible with hepatosplenic gammadelta T-cell lymphoma. However, with regard to EBV association, activated cytotoxic profile and cytological features they resembled non-hepatosplenic gammadelta TCL. EBV may play a role in this disease by inducing cellular activation.

Human carcinoma: early experience with phase-contrast X-ray CT with synchrotron radiation--comparative specimen study with optical microscopy.

Phase-contrast x-ray computed tomography (CT) indicates the distribution of the refractive index and has potential to reveal the structures inside soft tissues without a contrast agent. With a synchrotron x-ray source, phase-contrast x-ray CT with a triple Laue-case x-ray interferometer clearly differentiated various human pathologic tissues in the cases of hepatocellular carcinoma with cirrhosis and metastatic colon carcinoma to the liver, and the images closely corresponded to those obtained with low-magnification optical microscopy.

Clinical, immunohistochemical and phenotypic features of aggressive nodal cytotoxic lymphomas, including alpha/beta, gamma/delta T-cell and natural killer cell types.

Cytotoxic cells include natural killer (NK) cells and cytotoxic alpha beta and gamma delta T lymphocytes (CTLs). These cells express cytotoxic molecules of T-cell restricted intracellular antigen (TIA-1), and activated cytotoxic molecules of perforin, granzyme B, and FasL. Recent studies suggest that most extranodal T-cell lymphomas are derived from CTLs, and that NK cell lymphomas are extranodal. However, only a few nodal NK and cytotoxic lymphomas have been described so far. We present here the clinicopathological features of seven cases of nodal cytotoxic T and NK cell lymphomas. The study excluded anaplastic large-cell lymphomas expressing cytotoxic molecules. The neoplastic cells of all cases contained activated cytotoxic molecules of TIA-1, granzyme B, Fas ligand, and/or perforin. Phenotypically and genotypically, four cases showed alpha beta T cell type [CD2+, CD3+, T-cell receptor (TCR)-delta-1-, beta F1+, and TCR gene rearrangement], two cases showed gamma delta cell type [CD2+, CD3+, T-cell receptor (TCR) delta-1+, beta F1-, and TCR gene rearrangement], and one case showed NK cell type [CD2+, CD3-, CD56+, T-cell receptor (TCR) delta-1-, beta F1-, and TCR gene germline]. Using Southern blot analysis, Epstein-Barr virus (EBV) sequences were detected in six cases, and monoclonal terminal repeat proliferation was confirmed. In addition, in situ hybridization (ISH) studies for EBV showed EBV infection in almost all neoplastic cells. Clinically, all patients presented with peripheral lymphadenopathy in high clinical stages and showed an aggressive course. Hepatosplenomegaly was detected in six cases. During the course of the disease, bone marrow and extranodal invasion were noted in five cases. The nodal type showed an aggressive clinical course in all cases but one, as did the extranodal type. The nodal type varied in phenotype, but was closely associated with EBV infection.

Absence of cytotoxic molecules in CD8- and/or CD56-positive adult T-cell leukaemia/lymphoma.

Adult T-cell leukaemia/lymphoma (ATLL) cells usually exhibit a CD4+ (helper/inducer) phenotype (CD4+/8-/56-), and only a minority of tumours express the CD8 (cytotoxic/suppressor) or CD56 (natural killer [NK]-associated) antigens. TIA-1 is a cytotoxic granule-associated protein expressed in NK cells and cytotoxic T lymphocytes (CTLs). Granzyme B, perforin and Fas ligand (FasL) are also expressed in activated CTLs and NK cells. To clarify the cytotoxic potential of ATLL cells, immunohistochemistry was performed in CD8+ and/or CD56+ ATLL cells, using anti-TIA-1, anti-granzyme B, anti-perforin and anti-FasL antibodies. We studied nine cases of CD8+ and/or CD56+ ATLL, all of which exhibited monoclonal integration of human T-cell leukaemia virus type 1 (HTLV-1) proviral DNA. Four cases exhibited a CD8+/CD56- phenotype, four others had a CD8-/CD56+ phenotype, and one was CD8+/CD56+. All but one case also expressed the surface antigens CD3, TCR alpha beta, and CD4. Expression of granzyme B and TIA-1 were demonstrated in three and two cases, respectively, but none expressed perforin or FasL. In the control study, 10 cases with typical CD3+/4+/8-/56- ATLL demonstrated no expression of those cytotoxic-associated proteins. Our findings suggest that CD8 and/or CD56 positivity probably confer(s) no cytotoxic function on ATLL cells, and it is possible that CD8 and CD56 may be simply aberrant surface markers in ATLL.

Genotypic and phenotypic alterations in Epstein-Barr virus-associated lymphoma.

AIMS: Epstein-Barr virus (EBV) is associated with numerous reactive and neoplastic lymphoproliferative disorders. In vitro, EBV infection can transform B-lymphocytes and induce phenotypic alterations. This study presents the clinicopathological features of four cases with malignant lymphoma, which showed phenotypic and/or genotypic alterations during the course of the disease. METHODS AND RESULTS: To determine the type of EBV genotype, we performed polymerase chain reaction (PCR) for lymphocyte-defined membrane antigen (LYDMA) of EBV, subtype A/B and latent membrane protein (LMP)-1 deletion. In addition, we analysed the terminal repeat (TR) band of EBV and receptor genes (T-cell receptor gene, TCR; immunoglobulin gene heavy chain, IgH) for EBV-infected cell clonality. Double staining of cell markers (B, T-lymphocytes; histiocytes), and in-situ hybridization (ISH) for EBV were performed using tissues obtained during the course of the disease. The first case showed genotypic and phenotypic alterations of T-cell type to B-cell type. The first TCR rearrangement and T-cell markers (CD3+, CD4+, CD8-) were lost and IgH rearrangement and B-cell markers (CD19+, CD20+) were identified. During the course of the disease, EBV-TR bands changed in size; however, the EBV genotype type B, LMP1 deletion type, and single LYDMA band remained the same. The initial T-cell lymphoma clone was considered to be different from the latter B-cell lymphoma clone. The second case showed phenotypic alterations. The first B-cell marker (CD19+, CD20+, CD68-) changed to histiocytic markers (CD19-, CD20-, CD68+). However, IgH rearrangement and EBV-TR bands remained the same throughout the course of the disease and EBV genotype type A, LMP1 deletion type, and single LYDMA band remained unchanged. The third case showed phenotypic alterations. The B-cell marker (CD20+) was lost; however, IgH rearrangement of PCR and EBV genotype remained the same. In the second and third cases, the initial lymphoma clones were considered to be same as the latter clones. The last case showed lineage alterations from Hodgkin's disease to natural killer (NK) cell leukaemia. However, EBV genotype did not change. The second case and Hodgkin's disease showed LMP expression, but the first and third cases showed no LMP, and EBNA2 was not detected in all cases. CONCLUSIONS: We report the genotypic and/or phenotypic alterations in four patients with EBV-associated lymphoma/leukaemia. However, EBV genotype did not change in all four. These findings suggest that EBV might induce the cell marker and lineage alteration in vivo, as in vitro.

Decreased expression of telomerase-associated RNAs in the proliferation of stem cells in comparison with continuous expression in malignant tumors.

Telomerase, an enzyme associated with cellular immortality, is expressed by malignant tumor and stem cells, especially germ cells. Normal somatic cells, however, usually do not express telomerase. In the malignant tumor, deregulation of telomerase is thought to facilitate tumorigenesis and cellular immortality by providing cancer cells unlimited proliferation capacity. We investigated the relationship between proliferation activity and in situ expression of the telomerase RNA component (human telomerase RNA component, hTERC). In addition, in situ hybridization of the telomerase-associated proteins (telomerase-associated protein 1, TEP1; human telomerase reverse transcriptase, TERT), and MIB-1 immunohistochemistry for proliferation activity were performed, using the malignant tumors of adenocarcinoma, squamous cell carcinoma, and malignant lymphoma, and somatic tissues of testis, endometrium, stomach, skin, and lymph nodes. In the somatic tissues, the stem cells expressed telomerase-associated RNA, but no proliferation activity. When the proliferation activity of the stem cells increased, however, the telomerase-associated expressions decreased. In the malignant tumors, both proliferation activity and expression of the telomerase-associated RNA significantly increased. Deregulation of telomerase, in addition to proliferation activity, is associated with tumorigenesis.