Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Susceptibility to Helicobacter pylori infection may manifest itself as an increased prevalence of H. pylori infection, as reinfection after eradication, or as different clinical outcomes (gastritis, peptic ulcer disease, primary gastric B-cell lymphoma, or gastric cancer). These outcomes are likely to be a result of interaction between environmental and genetic factors. Genetic factors include both host genetic predisposition to infection as well as genetic differences in H. pylori strains. Twin studies indicate that the correlation coefficient for the relative importance of genetic effects (heritability) on acquisition of H. pylori infection is approximately 0.66. The remaining variance is accounted for by shared rearing environmental factors (20%), and non-shared environmental factors (23%), which contribute to the differences and not the similarities seen between family members. Molecular epidemiological studies of both the whole bacterial genome and of amplified regions between specific repetitive DNA sequences also suggest that there are disease-specific strains of H. pylori. There are, therefore, many different facets of susceptibility to H. pylori infection.
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PMID:Are there susceptible hosts to Helicobacter pylori infection? 786 44

Primary extranodal malignant lymphomas are most often localized in the stomach. In contrast to gastric carcinomas, primary gastric non-Hodgkin's lymphomas show an increasing incidence. According to their grade of malignancy they are divided into low-grade and high-grade non-Hodgkin's lymphomas and according to their immunophenotype into B-cell and T-cell non-Hodgkin's lymphomas. In most cases they show a B-cell phenotype while high-grade tumors are more frequent than those of low-grade malignancy. However, primary gastric Hodgkin's disease is still a rarity. A new entity, the so-called low-grade B-cell non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue (MALT) type, is characterized by a diffuse infiltrate of centrocyte-like cells intermingled with immunoblasts of the same clone, plasma cell differentiation of the tumor cells, lymphoepithelial lesions, and reactive intratumoral lymphoid follicles. It may secondarily transform into a high-grade B-cell lymphoma but remains limited to the stomach for a considerable period of time with a favourable prognosis. The most important prognostic factors of primary gastric lymphomas are stage at initial diagnosis, classification and grading according to the histopathological concept of the MALT, and depth of infiltration. Although a considerable number of early stage gastric lymphomas achieve complete remission after surgical therapy only, primary treatment of gastric lymphoma is still controverted, thus underlining the urgency of a multicenter prospective study. Chronic Helicobacter pylori infection may play a major role in the pathogenesis of low-grade B-cell lymphoma of MALT type. Complete remission of some cases of low-grade B-cell lymphoma of MALT type with concomitant Helicobacter pylori gastritis after Helicobacter pylori eradication may lead to a new pathogenetic, therapeutic, and prognostic concept.
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PMID:[Primary non-Hodgkin lymphoma of the stomach. A review with special reference to the MALT concept]. 793 42

From January 1 1994 to March 1 1995 we observed 6 patients with gastric low-grade B-cell lymphoma of MALT type in association with Helicobacter pylori infection. Endoscopically only 3 of the 6 patients presented with pathological findings. All but one patient with metastatic carcinoma received antibiotic therapy for Helicobacter pylori. Follow-up was not possible in one patient who died unexpectedly. In all 4 patients followed-up, eradication of Helicobacter pylori resulted in regression of the malignant lymphoma. During the median follow-up time of 7 months (2-13 months) no relapse of lymphoma was observed. Our results confirm that gastric low-grade B-cell lymphoma of MALT type can regress after eradication of Helicobacter pylori.
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PMID:[MALT-type low-grade B-cell lymphomas of the stomach and Helicobacter pylori]. 869 10

We describe the synchronous occurrence of gastric signet-ring cell adenocarcinoma and low-grade B-cell lymphoma of mucosa-associated lymphoid tissue in a patient with chronic gastritis and intestinal metaplasia. Histologic features of the mucosal inflammation, a follicular gastritis, were suggestive of a chronic Helicobacter pylori infection. Previous hypotheses concerning the relationship of long-standing gastritis and development of gastric carcinoma and lymphoma are supported by our findings.
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PMID:Gastric adenocarcinoma and low-grade B-cell lymphoma of mucosa-associated lymphoid tissue. 911 37

The development of synchronous gastric adenocarcinoma and primary gastric lymphoma is rare. We report a case of low grade B-cell lymphoma of mucosa associated lymphoid tissue intermingled with a gastric adenocarcinoma and without Helicobacter pylori infection. This observation leads to discuss the pathogenesis of these tumors and the role of Helicobacter pylori infection in the development of gastric lymphoma and carcinoma.
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PMID:[Association of a low-grade MALT lymphoma and a slightly differentiated adenocarcinoma of the stomach]. 922 Sep 99

In past years, association of primary cutaneous B-cell lymphoma (CBCL) with infection by Borrelia burgdorferi has been reported in a few patients. The evidence for a pathogenetic role was based on clinical grounds or raised titre of antibodies in serum. Both methods, however, do not prove the association between the micro-organism and the CBCL, especially in countries where infection by Borrelia burgdorferi is endemic. Moreover, the exact percentage of Borrelia burgdorferi-positive CBCL is not known. We retrieved from our files 50 cases of CBCL to perform PCR analysis of Borrelia burgdorferi DNA on paraffin-embedded tissue sections. Only patients with primary CBCL were selected. In all cases, monoclonality of the infiltrate was confirmed by immunohistological pattern of immunoglobulin light chains or molecular analysis of JH gene rearrangement, or both. Specific DNA sequences of Borrelia burgdorferi were identified in cutaneous lesions from 9 patients (follicle center lymphoma: 3/20; immunocytoma: 3/4; marginal zone B-cell lymphoma: 2/20; diffuse large B-cell lymphoma: 1/6). Specificity was confirmed by Southern blot hybridisation in all positive cases. We could show that Borrelia burgdorferi DNA is present in skin lesions from a small proportion of patients (18%) with various types of CBCL. Our results may have therapeutic implications. In analogy to Helicobacter pylori-associated MALT-lymphomas, which in some cases can be cured by eradication of Helicobacter pylori infection, a proportion of CBCL may be cured with antibiotic therapy against Borrelia burgdorferi. Although yet speculative, adequate antibiotic treatment for patients with primary CBCL should be considered before more aggressive therapeutic options are applied, particularly in countries where infection by Borrelia burgdorferi is endemic. PCR analysis of Borrelia burgdorferi DNA is a fast test that should be performed in all patients with CBCL to identify those who more likely could benefit from an early antibiotic treatment.
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PMID:Infection by Borrelia burgdorferi and cutaneous B-cell lymphoma. 933 90

A high incidence of Helicobacter pylori infection has been found in patients with gastric MALT (mucosa-associated lymphoid tissue) B-cell lymphoma. Recent studies have indicated that the aggressive strains of the bacterium containing the CagA gene may have direct effects on tumourigenesis. To investigate the involvement of CagA+ strains in MALT lymphomagenesis, a sensitive polymerase chain reaction (PCR)-based detection assay for the gene was developed. DNA extracts from paraffin sections of 123 H. pylori-related gastric biopsies from Italy were analysed, including 56 cases of chronic gastritis, 37 low-grade, and 30 high-grade MALT lymphomas: 30.3 per cent (17/56) of the gastritis cases, 37.8 per cent (14/37) of the low-grade, and 76.7 per cent (23/30) of the high-grade MALT lymphomas were found to contain the CagA gene. The frequency of CagA+ strain infection was significantly higher (P < 0.05) in high-grade than in low-grade MALT lymphoma or gastritis. These results suggest that high-grade gastric MALT lymphoma transformation may be more likely to occur following infection by CagA+ strains of H. pylori.
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PMID:High frequency of CagA+ Helicobacter pylori infection in high-grade gastric MALT B-cell lymphomas. 982 40

The aim of this study is to present a histopathologic and immunohistochemical analysis of primary gastric lymphomas which were reclassified according to the concept of mucosa associated lymphoid tissue (MALT). The resected specimens from 41 patients with primary gastric lymphoma were investigated retrospectively. Immunohistochemical study was done to analyze the immunophenotype and bcl-2 and p53 proteins expression. Twenty three of the cases had tumors mainly located in the antrum. Histologically, 12 were low grade and 20 were high grade B-cell lymphoma of MALT, 9 other B-cell nonHodgkin's lymphomas. Helicobacter pylori was identified in 72% of the cases. According to Musshoff's modification, most of the MALT lymphoma cases had stage I or II disease. There was significant difference between low and high grade cases, in respect to depth of invasion in gastric wall. Immunohistochemically, the neoplastic cells in all MALT lymphomas expressed B-cell phenotype. Bcl-2 protein was found to be expressed in 59% and p53 protein expression was detected in 72% of cases. Among the B-cell lymphoma of MALT, bcl-2 positivity decreased and p53 positivity increased significantly as the histological grade advanced. So, an inverse correlation was observed between the expression of bcl-2 and p53. In conclusion, most primary gastric lymphomas are low or high grade B-cell MALT lymphomas and appear to arise in MALT acquired as a reaction to Helicobacter pylori infection. Expression of bcl-2 and p53 in gastric lymphomas may be associated with transformation from low-grade to high-grade disease.
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PMID:Histopathologic features and expression of Bcl-2 and p53 proteins in primary gastric lymphomas. 1007 76

Infectious etiology has been confirmed only in a few lymphoproliferative disorders such as human T-cell lymphotropic virus in adult T-cell leukemia lymphoma, Epstein-Barr virus in African-type Burkitt's lymphoma and Hodgkin's disease, and Helicobacter pylori infection in primary gastric B-cell lymphoma. In recent years, Ferri and colleagues have found hepatitis C virus (HCV) association with non-Hodgkin's lymphoma (NHL) in Italy. The aim of our study was to determine the HCV association in NHL patients in Antalya. Forty-eight patients (22 women and 26 men, with a median age of 52 years) with NHL were included in the study. The control group consisted of 28 patients with various hematological disorders (11 women and 17 men with a median age of 50 years). Anti-HCV antibodies were investigated in 48 patients, and HCV RNA was assessed in 35 of them. Anti-HCV antibodies were found to be negative in the NHL group, but HCV RNA was positive in the serum of three patients (8.6%), who were diagnosed with diffuse small cell lymphoma (19%). Anti-HCV antibodies and HCV RNA were negative in the control group. Since HCV association with NHL has previously been reported in Italy, it is likely that both genetic and environmental factors in the Mediterranean sea-region may be involved in the oncogenesis in HCV RNA-positive patients. Multicenter studies with large patient groups will disclose the true association of HCV with NHL in Turkey.
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PMID:Hepatitis C virus association with non-Hodgkin's lymphoma. 1043 70

B-cell lymphomas of the gastrointestinal (GI) tract have represented a field of extensive research ever since a close association was shown with chronic inflammatory processes such as Helicobacter pylori infection. Much evidence has accumulated to suggest that the mucosa-associated lymphoid tissue (MALT) induced by inflammation and autoimmune processes is the environment which gives rise to the small cell lymphomas of the GI tract (e.g. extranodal marginal B-cell lymphoma according to REAL). The small B-cell lymphoma may then progress to the large cell variants. Hence, B-cell lymphomas of the GI tract may present a model for lymphomagenesis and progression. In this review, recent cytogenetic data are discussed which yield new insights into the biology of gastrointestinal lymphomas.
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PMID:Chromosomal aberrations in lymphomas of the gastrointestinal tract. 1061 47


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