Compartment analysis of T cell receptor gamma--and immunoglobulin V(H) rearrangements by microdissection in patients with malt lymphoma and chronic gastritis with lymphatic hyperplasia.

The interpretation of clonality within H. pylori-associated gastritis and low-grade MALT lymphoma remains controversial. Due to the observation of MALT lymphoma regression after H. pylori eradication, new definitions concerning the border between benign reactive lesions and malignant gastric lymphoma are needed. Gene rearrangements for immunoglobulin heavy-chain in low-grade MALT lymphoma (N= 12) and H. pylori-associated chronic gastritis with lymphatic hyperplasia (N= 13) were analyzed by microdissection and polymerase chain reaction. Furthermore, T cell receptor-gamma chain rearrangements were analyzed by gene scan analysis. In 11 of 12 cases with initial low-grade MALT lymphoma, intraepithelial and subepithelial B cell rearrangements showed a restricted usage of the immunoglobulin heavy-chain 3. In H. pylori-associated chronic gastritis, the intraepithelial B cell compartment showed an oligoclonal the immunoglobulin heavy-chain rearrangement pattern with a predominance of VH3. The subepithelial compartment did not show any restrictive immunoglobulin heavy-chain gene usage. Additionally a mono- to oligoclonal rearrangement pattern of the T cell receptor-y chain was observed in low-grade MALT lymphoma, whereas an oligoclonal pattem was observed in chronic gastritis. Our data provide evidence that low-grade MALT lymphoma may start within the epithelium and subsequently infiltrate the subepithelial compartment. The observation of a mono- to oligoclonal TCR-gamma rearrangement suggests that an antigen selecting process also takes place within reactive T cells. Combining TCR-gamma gene scan analysis with IgH chain rearrangement analysis might help in discriminating between chronic gastritis and initial MALT lymphoma in questionable cases.     

Immunohistochemical comparison of CD5, lambda,and kappa expression in primary and recurrent buccal Mucosa-associated lymphoid tissue (MALT) lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of extranodal marginal zone B-cell lymphoma and is a distinct subtype of non-Hodgkin's lymphoma.Primary MALT lymphomas can also occur in the oral cavity, although their appearance in this location is rare. The neoplastic cells of which MALT lymphomas are composed express B-cell antigens and show monotypic immunoglobulin expression with light-chain restriction.Although neoplastic MALT lymphoma cells do not express CD5, previous studies have shown that CD5 positive MALT lymphomas are more prone to dissemination than those that do not express CD5. Moreover, there are some reports that describe kappa- and lambda- dual light chain expression in B cell malignant neoplasms.A 66-year-old Japanese woman with swelling of the right buccal mucosa was referred to our hospital. The lesion was excised and was pathologically diagnosed as a MALT lymphoma tumor with a t(11;18)(q21;q21) chromosome translocation.Swelling of the right buccal mucosa recurred 2 years later. The recurrent tumor was then excised and pathologically diagnosed as MALT lymphoma.Immunohistochemical examination of CD5, lambda, and kappa expressions revealed that the primary tumor was positive for CD5, kappa, and lambda, but the recurrent tumor was weakly positive for CD5 and kappa.With respect to lambda positivity, the recurrent tumor showed negativity.Our study suggests that immunohistochemical expression of CD5, kappa, and lambda in oral MALT lymphoma have the risk of recurrence.We first described the recurrence of CD5 positive MALT lymphoma in the oral cavity and compared the immunohistochemical expressions of CD5, lambda, and kappa between the primary and recurrent tumors.     

Involvement of immunoglobulin heavy- and light-chain (kappa) gene clusters in a human B-cell translocation, t(2;14)

The breakpoints of a translocation, t(2;14)(p11;q32), detected in an Epstein-Barr virus-transformed lymphoid B-cell line were mapped by Southern analysis, field-inversion gel electrophoresis, and in situ hybridisation. The translocation involved the immunoglobulin light-chain (kappa) locus on chromosome 2 and the heavy-chain locus on chromosome 14. The breakpoint on chromosome 2 was between VK and CK, most likely within JK. The chromosome 14 break was located within the VH cluster, no more than 220 kb 5' of the productively rearranged JH locus. The translocation probably resulted from an aberrant rearrangement of the kappa light-chain genes.     

Comparison of localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma with and without Helicobacter pylori infection

BACKGROUND: The clinical features and clinical course of Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma are unclear and a treatment strategy has not yet been established. AIM: To clarify the clinical differences between H. pylori-positive and H. pylori-negative gastric MALT lymphoma, we compared these two types of gastric MALT lymphoma. MATERIALS AND METHODS: Fifty-seven patients with localized gastric MALT lymphoma were studied. H. pylori infection was present in 41 and absent in 16. Treatment consisted of antibiotic therapy and/or 30 Gy radiation therapy. Response assessment was performed every 3-6 months by esophagogastroduodenoscopy including gathering biopsy samples, endoscopic ultrasonography, clinical examination, and various imaging procedures. The median follow-up period was 37 months. RESULTS: There were no significant differences between H. pylori-positive and H. pylori-negative gastric MALT lymphoma patients in terms of sex, age, stage, gross phenotype, affected area of the stomach, or the presence of monoclonality. Complete regression was achieved with antibiotic therapy against H. pylori-negative gastric MALT lymphoma in one of nine patients (11.1%), compared to 28 of 38 patients (73.7%) with H. pylori-positive gastric MALT lymphoma (p < .001). Radiation therapy showed high effectiveness for the local control of H. pylori-negative or antibiotic-resistant gastric MALT lymphoma (92.9%), although distant recurrence was recognized in three of 14 patients (21.4%). Two of 16 patients (12.5%) with H. pylori-negative gastric MALT lymphoma died because of the transformation of the disease into diffuse large B-cell lymphoma. There was a significant difference in both the overall and cause-specific survival rate between the two groups (p = .038). CONCLUSION: Radiation therapy is the effective treatment for H. pylori-negative or antibiotic-resistant localized gastric MALT lymphoma. However, careful systemic follow-up for distant involvement should be required. Transformation into diffuse large B-cell lymphoma is thought to be the important cause of death in patients with gastric MALT lymphoma.     

Primary mediastinal B-cell lymphoma: detection of BCL2 gene rearrangements by PCR analysis and FISH

Primary mediastinal large B-cell lymphoma (PMBCL) has a characteristic clinical presentation, morphology, and immunophenotype, representing a clinically favorable subgroup of diffuse large B-cell lymphoma (DLBCL). By gene expression profiling (GEP), PMBCL shares features with classical Hodgkin lymphoma (cHL). Of further interest, BCL6 gene mutations and BCL6 and/or MUM1 expression in a number of PMBCLs have supported an activated B-cell (ABC) origin. Several studies, including GEP, have failed to detect BCL2 gene rearrangements (GRs) in PMBCL. An index case of t(14; 18)+ PMBCL prompted our study of the incidence of BCL2 GRs in PMBCL by polymerase chain reaction (PCR)/fluorescence in situ hybridization (FISH) analyses and its possible clinical impact. Twenty-five retrospectively identified, well-defined PMBCLs (five with cytogenetics) from three institutions were analyzed for a BCL2 GR by PCR/FISH analyses. The formalin-fixed, paraffin-embedded tissue blocks of 24 available cases were also analyzed by BCL2 immunohistochemistry (IHC). Of the five with cytogenetics, two had a t(14; 18) (q32; q21). Of the 25 analyzed by PCR, 2 had no amplifiable DNA (aDNA), including 1 t(14; 18)+ case. Of those with aDNA, two showed a BCL2 GR; by FISH analysis, three demonstrated a BCL2 GR. BCL2 protein expression by IHC analysis was variably detected in 21 out of 24 (strongly, uniformly expressed: 6, including all with a t(14; 18) or a BCL2 gene rearrangement; moderately weakly expressed in a subset of the malignant cells: 15). Available clinical follow-up of this BCL2+ subset showed a similar course to the other PMBCL cases. Our results imply that a subset of PMBCL [(4 out of 24 analyzed) in our series] may be of GC origin. A larger study is necessary to determine any clinical significance.     

Analysis of immunoglobulin and T-cell receptor gene rearrangement in cytologic specimens

Recombinant DNA techniques to detect the rearrangement of genes encoding immunoglobulins and T-cell-antigen receptors have been used to identify clonality in lymphoid lesions. To determine the utility of such techniques in cytologic specimens, DNA was analyzed in 24 effusions and 6 fine needle aspirates. Immunophenotypic studies were also performed on the 19 specimens with suspected hematopoietic malignancies. Sufficient material for DNA analysis was present in 28 of the 30 specimens. Immunoglobulin or T-cell-receptor gene rearrangement was present in 13 specimens with atypical cytologic findings; DNA studies provided more information than did the immunologic studies in 3 cases. One T-cell malignancy showed T-cell receptor and heavy-chain gene rearrangement, and one B-cell malignancy showed immunoglobulin and T-cell receptor gene rearrangement. In all patients except one with no evidence of gene rearrangement, the morphologic and immunologic studies also favored a reactive process. Control specimens showed a germline configuration. This study demonstrated that DNA gene rearrangement studies are feasible on many cytologic specimens and may be useful in diagnostically difficult cases.     

人类免疫缺陷病毒阴性的阴道残端浆母细胞淋巴瘤一例并文献复习

目的:浆母细胞淋巴瘤(PBL)为罕见的、侵袭性极强的B细胞淋巴瘤,好发于HIV阳性患者的口腔,本文报道了目前国内外首例HIV阴性的原发于阴道残端的PBL,并通过文献复习总结了PBL的临床病理学特征、诊断及鉴别诊断、治疗及预后。方法:回顾分析该病例的临床病理学资料,并结合国内外相关文献进行讨论。结果:该患者诊断明确,HIV阴性,以阴道残端起病,免疫组化示MUM-1阳性,不表达CD20、CD79a和PAX-5,Ki-67阳性率73%。EBER原位杂交阴性。分子学诊断结果示:样品免疫球蛋白基因发生克隆性重排,未检到TCR基因克隆性重排。CHOP样方案疗效不佳,部分缓解后疾病快速进展。该患者从确诊至死亡时间为10.3个月。结论:PBL罕见,病情进展迅速,预后差,生存期短,在进行阴道残端肿瘤的诊断及鉴别诊断时,阴道残端PBL应纳入鉴别范围。     

The AKT1 proto-oncogene maps to human chromosome 14, band q32

The human AKT1 gene is the proto-oncogene of the viral oncogene v-akt. The AKT1 gene has been localized to human chromosome 14, band q32, proximal to the heavy-chain immunoglobulin locus (IGHM), by analysis of human-hamster somatic cell hybrids and by in situ hybridization. Chromosome rearrangements of this band which occur in T-lymphoid malignancies and Hodgkin's disease may affect the AKT1 gene.     

c-myc and immunoglobulin kappa light chain constant genes are on the 8q+ chromosome of three Burkitt lymphoma lines with t(2;8) translocations.

We have determined the localization of c-myc and the immunoglobulin kappa light chain genes on the 8q+/2p- chromosomes of the three Burkitt lymphoma lines BL21, LY66 and LY91 with t(2;8) translocation by in situ hybridization. BL21 is characterized by a complex translocation in which a piece of chromosome 9 appears to be located between the fragments of chromosome 8 and 2 on the 8q+ chromosome. Our data indicate that in all three cell lines the c-myc gene is located on the 8q+ chromosome proximal to the breakpoint in band 8q24. In all cell lines examined the cluster of kappa variable genes has remained on the 2p- chromosome. In LY91 cells the major part of the joining region remained on 2p-, while the joining region has moved to 8q+ in the cell lines BL21 and LY66. In all three cell lines the constant kappa light chain gene was found on the 8q+ chromosome. The fact that an essentially identical pattern was found in the cell line BL21, with the complex translocation, suggests that the insertion of the piece of chromosome 9 into the 8q+ chromosome might be a secondary event. Our present data fit into the concept that in all Burkitt lymphoma lines investigated so far, including cases with t(8;14) and the variant translocations t(2;8) and t(8;22), the c-myc gene becomes situated at the 5' side of an immunoglobulin constant gene. This may have implications for the generation of somatic mutations in the coding and non-coding part of the c-myc gene.     

Helicobacter pylori (H. pylori) molecular signature in conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma

Conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma is an extranodal marginal zone B-cell lymphoma that is characterized by an exaggerated clonal expansion of B cells, which implicate a pathological proliferative response to antigen(s) including bacteria. Helicobacter pylori (H. pylori) infection is recognized as one of the causative agents of gastric MALT lymphoma; however, it has not been reported in extra gastric MALT lymphoma. We studied 5 patients (4 adults and 1 child) with salmon-colored conjunctival lesions. One patient also had a history of abnormal bone marrow biopsy a year earlier with lymphoid aggregates involving 5% of the overall bone marrow. The conjunctival lesions of the 5 patients were biopsied. Histopathological diagnoses were consistent with conjunctival MALT lymphoma. Lymphoma and normal conjunctival cells were microdissected using laser capture microscopy or manual techniques. DNA was extracted and subjected to PCR amplification using H. pylori gene-specific primers from the urease B and vac/m2 gene. Cells from chronic conjunctivitis (normal lymphocytes), conjunctival human T-cell lymphotropic virus type-1/adult T-cell leukemia/lymphoma (HTLV-1/ATL), and orbital B-cell lymphoma were also microdissected, processed and analyzed. PCR amplification and Southern blot hybridization demonstrated H. pylori DNA in the conjunctival MALT lymphoma cells of 4/5 cases. The negative case was the one with a history of abnormal bone marrow. In contrast, H. pylori gene was not detected in normal conjunctival cells from the cases of MALT lymphoma or the lymphocytes, ATL and orbital B-lymphoma cells from the controls. These data suggest that H. pylori may play a role in conjunctival MALT lymphoma.     

Somatic DNA recombination yielding circular DNA and deletion of a genomic region in embryonic brain

In this study, a mouse genomic region is identified that undergoes DNA rearrangement and yields circular DNA in brain during embryogenesis. External region-directed inverse polymerase chain reaction on circular DNA extracted from late embryonic brain tissue repeatedly detected DNA of this region containing recombination joints. Wide-range genomic PCR and digestion-circularization PCR analysis showed this region underwent recombination accompanied with deletion of intervening sequences, including the circularized regions. This region was mapped by fluorescence in situ hybridization to C1 on mouse chromosome 16, where no gene and no physiological DNA rearrangement had been identified. DNA sequence in the region has segmental homology to an orthologous region on human chromosome 3q.13. These observations demonstrated somatic DNA recombination yielding genomic deletions in brain during embryogenesis.     

A prospective analysis of low-grade gastric malt lymphoma after Helicobacter pylori eradication

BACKGROUND: Primary gastric low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is known to be successfully treated with anti-Helicobacter pylori (H. pylori) therapy alone. However, there are few reports on long-term results after eradication therapy. The aims of this study were to analyze the rate and the interval to reach complete remission (CR), and to assess the rate and the factors affecting recurrence of MALT lymphoma. MATERIALS AND METHODS: Between 1996 and 2003, a total of 90 H. pylori-infected patients with low-grade MALT lymphoma were included in this study. For initial staging, endoscopic ultrasonography, chest-abdomen-pelvis CT scans, and bone marrow examination were taken. All patients were made to take anti-H. pylori therapy for 14 days. Tumoral response was assessed by endoscopy every 3 months till CR and every 6 months after achieving CR. RESULTS: Among 90 treated patients, 85 (94.4%) reached CR. The median interval to CR was 3 months (range, 1-24). Seventy-nine (92.9%) patients were in CR at 12 months. Median follow-up period after CR was 45 months (range 15-109). Among 77 patients who were followed-up after CR, 8 (10.4%) patients were proved with recurrence of MALT lymphoma. Cumulative recurrence rate was 2.7, 11.5, and 12.2% at 1, 2, and 3 years. The presence of H. pylori was only a significant risk factor affecting recurrence. CONCLUSIONS: The status of H. pylori is the most important risk factor affecting recurrence. Therefore, adequate eradication regimen and accurate regular evaluation for H. pylori status are needed during follow up of primary gastric low-grade B-cell MALT lymphoma.     

Increased apoptosis and angiogenesis in gastric low-grade mucosa-associated lymphoid tissue-type lymphoma by Helicobacter heilmannii infection in C57/BL6 mice

Helicobacter heilmannii has been reported to cause gastric low-grade mucosa-associated lymphoid tissue-type (MALT) lymphoma, but its precise pathophysiological mechanism remains to be clarified. We recently established a model of gastric B-cell MALT lymphoma in C57BL/6 mice by means of peroral infection of H. heilmannii primarily obtained from cynomolgus monkeys. Using this model, macroscopic, immunohistochemical, and electron microscopic observations of MALT lymphomas were carried out in order to examine the development of apoptosis and angiogenesis. Enhancement of the microvascular network and an increase in vascular endothelial growth factor-A were detected in the central region of the MALT lymphoma tissue in the infected mouse stomach, while vascular endothelial growth factor-C was detected at the margins of the MALT lymphomas. In addition, many H. heilmannii-invaded parietal cells showed caspase-3 immunoreactivity in the fundic mucosal tissue surrounding the MALT lymphoma. In conclusion, in H. heilmannii-induced MALT lymphoma, enhanced immunoreactivity of vascular endothelial growth factor-A and factor-C was observed in areas encircled by increased parietal cell apoptosis, which indicates the pathophysiological relevance of both angiogenesis and apoptosis in MALT lymphoma formation.     

Molecular cytogenetics of IGH rearrangements in non-Hodgkin B-cell lymphoma

Rearrangements involving the IGH gene have been identified in about 50% of non-Hodgkin B-cell lymphomas (NHLs) and correlated to clinically relevant subgroups. However, the detection rate largely varied with the technique used. We analyzed the incidence of IGH rearrangements using several fluorescence in situ hybridization (FISH) techniques on metaphases obtained from 96 patients with nodal NHL. An IGH rearrangement was identified in 71 cases (74%). A t(14;18)(q32;q21) was found in 37 of the 42 follicular lymphomas (88.1%) studied and a t(11;14)(q13;q32) in 12 of the 14 mantle cell lymphomas (85.7%). IGH rearrangements were identified in 21 of the 40 diffuse large B-cell lymphomas (52.5%), including seven t(14;18)(q32;q21) and four t(3;14)(q27;q32). Conventional cytogenetics was uninformative in several cases. However, the complemented analysis using 24-color FISH, chromosomal whole paints, telomeric probes and locus specific identifiers enabled us to characterize complex and/or masked IGH translocations in follicular lymphomas and mantle cell lymphomas and to identify all the chromosomal partners involved in IGH rearrangements in diffuse large B-cell lymphomas. This study shows the interest of using metaphase FISH in addition to conventional cytogenetics. Following banding techniques, FISH with the IGH dual color probe can be the first approach in NHL, after which chromosome painting and 24-color FISH can be used to identify the chromosomal partners involved in IGH rearrangements. The identification of these genes is of utmost importance for a better understanding of the molecular mechanisms involved in the genesis of lymphoma.     

N-aryl-piperidine-4-carboxamides as a novel class of potent inhibitors of MALT1 proteolytic activity

Starting from a weak screening hit, potent and selective inhibitors of the MALT1 protease function were elaborated. Advanced compounds displayed high potency in biochemical and cellular assays. Compounds showed activity in a mechanistic Jurkat T cell activation assay as well as in the B-cell lymphoma line OCI-Ly3, which suggests potential use of MALT1 inhibitors in the treatment of autoimmune diseases as well as B-cell lymphomas with a dysregulated NF-κB pathway. Initially, rat pharmacokinetic properties of this compound series were dominated by very high clearance which could be linked to amide cleavage. Using a rat hepatocyte assay a good in vitro-in vivo correlation could be established which led to the identification of compounds with improved PK properties.     

Identification of paracaspases and metacaspases: two ancient families of caspase-like proteins, one of which plays a key role in MALT lymphoma

Caspases are cysteine proteases essential to apoptosis. We have identified two families of caspase-like proteins, Paracaspases (found in metazoans and Dictyostelium) and metacaspases (found in plants, fungi, and protozoa). Metazoan paracaspase prodomains contain a death domain and immunoglobulin domains. Several plant metacaspase prodomains contain zinc finger motifs resembling those in the plant hypersensitive response/cell death protein Isd-1. The human paracaspase prodomain binds Bcl10, a protein involved in the t(1;14)(p22;q32) translocation of mucosa-associated lymphoid tissue (MALT) lymphoma. Another MALT lymphoma translocation, t(11;18)(q21;q21), fuses the IAP-2 gene to the MLT1/MALT1 locus, which encodes the human paracaspase. We find that this fusion activates NF-kappaB and that the caspase domain is required for this function, since mutation of the conserved catalytic cysteine attenuates NF-kappaB activation.     

Breakage on chromosome 2 brings the Ck gene to a region 3' of c-myc in a Burkitt's lymphoma line carrying a (2;8) translocation

We have shown using in situ hybridization that the constant region of the kappa light chain immunoglobulin gene (Ck) is translocated from chromosome 2 to chromosome 8 in Burkitt's lymphoma cells with a (2;8) translocation. The Ck gene then ends up adjacent to and on the 3' side of c-myc. The breakpoint probably falls between the gene for the variable region of the kappa light chain (Vk) and the Ck gene.