Birgit Alpen

Helicobacter and gastric MALT lymphoma.

Helicobacter pylori infection is a pre-MALT lymphoma condition. H pylori eradication leads to complete remission in 80% of low grade stage E1 lymphomas, with a yearly recurrence rate of approximately 5%. The possibility for complete remission in high grade lymphomas needs to be investigated in prospective studies. In addition, the significance of persistent B cell monoclonality (stable disease? danger of relapse? regression of monoclonality?) needs to be investigated in follow up studies.

What Role Does Helicobacter pylori Eradication Play in Gastric MALT and Gastric MALT Lymphoma

The concept of mucosa-associated lymphoid tissue (MALT) has been introduced to differentiate biological functions from behavior of nonnodal vs. nodal lymphoid tissues. Lymphomas arising from MALT also behave differently than typical nodal lymphomas. In contrast to other tissues, MALT in the stomach is almost exclusively a result of Helicobacter pylori infection. Thus, MALT is part of the host defense against the pathogen H. pylori. Consequently, lymphomas arising from gastric MALT may be a clonal evolution starting from the infection. In low-grade gastric MALT lymphoma, cure of the infection may induce complete histological remission in the majority of patients. Investigators have recently reported that complete remission rate is between 70% and 80%. In an extended analysis, we have treated 84 patients with low-grade gastric MALT lymphoma in stage El, using a dual regimen to eradicate H. pylori. Complete remission was observed in 68 (80%) patients; a partial remission was found in 4 patients. In contrast, 12 patients showed no change and were referred to alternative treatment. In patients in complete remission, a polymerase chain reaction assay for the rearranged immunoglobulin heavy-chain gene remained positive in many cases. Together with data from the literature, these data suggest that the majority of patients with low-grade gastric MALT lymphomas in stage El respond to eradication of H. pylori. Longer follow-up investigations are necessary to determine if remissions indicate a cure from the disease.

Ongoing somatic mutations and clonal expansions after cure of Helicobacter pylori infection in gastric mucosa-associated lymphoid tissue B-cell lymphoma.

PURPOSE Although most patients with primary gastric low-grade mucosa-associated lymphoid tissue (MALT) B-cell lymphoma experience complete endoscopic and histologic remission after the cure of Helicobacter pylori infection, in many patients, the polymerase chain reaction (PCR) still detects monoclonal B cells in the gastric mucosa. The present study asked whether the lymphoma immunoglobulin VH (IgVH) sequences remained stable in patients with gastric MALT lymphoma after H pylori eradication. PATIENTS AND METHODS Eight patients with stage EI disease treated with H pylori eradication were analyzed before and at different time points after the cure of the infection. After the amplification of IgVH genes from DNA extracted from gastric biopsy specimens, monoclonal PCR products were cloned and multiple clones (43 to 105) were sequenced per patient. RESULTS Mutations were detected in all lymphoma VH sequences, which suggested germinal center or postgerminal center origin of the lymphoma B cells. In five of the eight patients, clonal heterogeneity was observed at diagnosis or during follow-up. Genealogical analysis of shared and unshared mutations showed that the process of somatic mutations was ongoing after H pylori eradication in four of the five patients who showed clonal instability. Ongoing mutations were observed in three of the four patients who completely responded to H pylori eradication, but in only one of the four patients who did not respond or who partially responded. CONCLUSION In low-grade gastric MALT lymphomas, an ongoing process of somatic hypermutation and antigen selection can be detected after the therapeutic removal of the underlying stimulus H pylori. These data point to the relevance of yet unknown antigens that drive this disease. In addition, they challenge the view that these lymphomas may be cured solely by the eradication of H pylori.

Underestimation of inversion (16) in acute myeloid leukaemia using standard cytogenetics as compared with polymerase chain reaction: results of a prospective investigation

In order to determine whether the polymerase chain reaction (PCR) is more suitable for the detection of inversion (16) as compared with standard cytogenetics, we prospectively investigated a total of 132 cases of de novo acute myeloid leukaemia (AML) (n=121) and secondary AML after myelodysplastic syndromes (MDS) (n=11) using a sensitive and nested PCR procedure to detect the fusion transcripts CBFβ‐MYH11. All patients were recruited within 10 months in an ongoing multicentre AML‐trial. In addition, several cases from a retrospective molecular analysis were included. The data were compared with standard cytogenetics performed in a central laboratory. Of the 132 prospective AML cases, five patients (3.7%) harboured inv(16) upon conventional cytogenetics. In all cases fusion transcripts CBFβ‐MYH11 were detected using PCR. In addition in two patients fusion transcripts were detected, although cytogenetics revealed a normal karyotype. In the group of patients analysed retrospectively, four patients harboured fusion transcripts specific for CBFβ‐MYH11; cytogenetics were normal in one case, and could not be evaluated in two cases. These data show that PCR may be a better means to detect inv(16) in AML. Since inv(16) may have prognostic impact in AML, detection of this aberration seems important in the clinical management of AML patients.

Helicobacter pylori eradication therapy in gastric high grade Hon Hodgkin's lymphoma (NHL)

AbstractBackground: Primary gastric low-grade lymphoma of the mucosa associated lymphoid tisue (MALT) develops on the background of a chronic Helicobacter pylori (H. pylori) infection. Stable remissions can be induced by H. pylori eradication therapy as shown in clinical trials. In 8 cases of high-grade gastric lymphomas remissions after H. pylori eradication were observed retrospectively. Aim: We started a pilot-trial to investigate the value of H. pylori eradication therapy in early gastric high-grade B-cell lymphoma prospectively. Patients and Methods: So far, two H. pylori positive patients with high-grade B-cell lymphoma of the stomach stage I B are included. They received a triple eradication-therapy (Clarithromycin 500 mg/d, Metronidazol 800 mg/d and Omeprazol 40 mg/d) for 7 days. Endoscopic controls are performed every 4 weeks. Results: Both patients became H. pylori negative after eradication therapy. One patient achieved complete remission (CR) 38 days after eradication. The continuous complete remission lasts now for 170 days. The second patient received only a partial remission (PR) 4 weeks after eradication and showed a slight progress 4 weeks later. He presently receives chemotherapy (CHOP). Conclusions: Patients with early high-grade gastric B-cell lymphomas should receive H. pylori eradication only within clinical trials. It seems to be possible to induce remissions of early high-grade gastric B-cell lymphomas with exclusive H. pylori eradication therapy. The stability of remission remains to be unclear and should be evaluated by following up the patients closely.

Ongoing Monoclonal B-Cell Proliferation Is Not Common in Gastric B-Cell Lymphoma After Combined Radiochemotherapy

PURPOSE Gastric marginal-zone B-cell lymphoma (MZBCL) of the mucosa-associated lymphoid tissue (MALT) is associated with chronic Helicobacter pylori gastritis. Stable complete remission (CR) can be induced by H pylori eradication. Whether this is paralleled by cure of the lymphoma remains unclear. Persisting monoclonal bands for immunoglobulin heavy chain variable region (VH) representing the lymphoma clone have been described in up to 50% of patients in CR. This retrospective study investigated whether this phenomenon also occurs after radiochemotherapy. PATIENTS AND METHODS Biopsy samples of 20 patients receiving chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone and irradiation were analyzed before and after therapy. Study patients had Ann Arbor stage I/II primary gastric cancer, including four cases of MZBCL of MALT type, 12 cases of diffuse large-cell lymphomas (DLCL), and four cases of mixed MALT type/DLCL. Polymerase chain reaction (PCR) for VH rearrangement was performed. Monoclonal PCR products were cloned and sequenced. RESULTS Fourteen of 20 patients had a monoclonal or oligoclonal band distribution at diagnosis converted into polyclonal pattern after radiochemotherapy. Of the remaining six patients, two were lost to follow-up. One patient did not respond and died of progressive disease. PCR in this patient showed persistent B-cell clonality. In three patients, the initial PCR showed a polyclonal pattern and thus could not be evaluated during follow-up. CONCLUSION In contrast with H pylori eradication alone, radiochemotherapy results in clearing of monoclonal cells during follow-up. This may result in better elimination of residual lymphoma cells. Further study is needed to determine whether this translates into lower risk of relapse.

Etiology and therapy of Helicobacter pylori -associated gastric lymphomas

The WHO separates marginal zone B-cell lymphomas (MZBL) of nodal and extranodal type. Both arise from memory B cells of the marginal zone. Extranodal MZBL of the mucosa-associated lymphatic tissue (MALT) have characteristic features such as homing in epithelial tissue, lymphoepithelial destruction, and a very indolent clinical course. They arise in epithelial tissues normally devoid of lymphatic cells, where the lymphatic tissue was acquired after, for instance, a chronic infection. The best example here is infection of the stomach with Helicobacter pylori (Hp). Besides the classical association with gastric MALT lymphomas, there have been reports in which an association between Hp and diffuse large B-cell lymphoma (DLBCL) has been observed as well. Consequently, cure of Hp infection resulted in remission induction not only in gastric MALT lymphomas, but also in some patients with very limited stages of DLBCL of the stomach. In addition to the association with Hp, progress has been made with regard to MALT lymphoma biology. Translocation t(1;14) involving the Bcl-10 gene, and translocation t(11;18) involving a novel gene called MLT1, both result in activation of the crucial transcription factor NF-kappaB. These genetic events seem specific in that they have been observed only in MALT lymphomas. Once present, at least the more frequently observed translocation t(11;18) renders cells resistant to cure of Hp infection. Another clinically important question is that in many patients in complete remission after cure of Hp infection, detection of minimal residual disease is positive. Whether these cells are normal memory B cells (with the identical B-cell rearrangement as the original lymphoma clone), or dormant lymphoma cells, is unclear at present. In patients not responding to cure of Hp infection, several treatment options are discussed. MALT lymphomas have opened up a new discussion of lymphoma biology and have thus been called a model disease.

Bedeutung der Helicobacter-pylori-Infektion für die Pathogenese und Therapie von MALT-Lymphomen des Magens

The Role of Helicobacter pylori Infection for the Development and Treatment of Gastric MALT Lymphomas Since 1983, it is well known that mucosa-associated lymphoid tissue (MALT)-type lymphoma of the stomach is due to chronic Helicobacter pylori (H. pylori) infection. Many epidemiological, biological, and moleculargenetic studies have implicated the role of H. pylori in lymphomagenesis. Nowadays, more than 650 patients with gastric MALT lymphoma worldwide have been treated with antibiotics for H. pylori infection, achieving a complete remission in about 75% of cases. Clinical predictive factors help to stratify patients into risk groups, and help to predict the probability of lymphoma remission. New insights into cytogenetics have also contributed to the understanding of lymphomagenesis, and with the newly identified translocation t(11;18)(q21;q21) we might have also a genetic factor at hand to predict treatment response.