The role of Helicobacter pylori in primary gastric MALT lymphoma

Is mucosa-associated lymphoid tissue lymphoma an infectious disease? Role of Helicobacter pylori and eradication antibiotic therapy (Review)

Mucosa-associated lymphoid tissue lymphoma (MALT) is seldom considered a diagnosis hypothesis in symptomatic patients. These lymphomas present as a main risk factor for chronic gastritis due to Helicobacter pylori infection. H. pylori leads to chronic inflammation, producing lymphoid tissue in the stomach mucosa (MALT) possibly leading to malignant transformation. Even though H. pylori remains one of the most important factors in the development of MALT lymphoma, it is not mandatory in the evolution of MALT lymphoma since high-grade lymphomas present a lower prevalence of H. pylori. The prevalence of H. pylori is indirectly proportional with the progression into the gastric wall. Mucosal and submucosal MALT lymphomas have a higher prevalence of the bacteria. However, genetic factors remain a risk factor especially if eradication treatment fails. Even though a low percentage of MALT lymphomas are H. pylori-negative, some respond to antibiotic eradication treatment. This can be explained either by the immunomodulatory effect of antibiotics or by other infectious sources such as Helicobacter heilmannii and Campylobacter jejuni (small bowel lymphoma). Treatment in MALT gastric lymphoma was a breakthrough since it was the first time in oncology where tumours were cured by antibiotic therapy, leading us to wonder if MALT lymphomas are infectious disease or not?

The Epidemiology of Gastric Cancers in the Era of Helicobacter pylori Eradication: A Nationwide Cancer Registry-Based Study in Taiwan

BACKGROUND

Helicobacter pylori eradication has been shown to decrease gastric adenocarcinoma risk. The epidemiology of gastric lymphoma, which is also associated with H. pylori, and other rare subtypes of gastric cancer is less clear. This study comprehensively evaluated the incidence trend and the survival of gastric cancer in Taiwan by histologic subtype.

METHODS

The incidence trends of gastric cancer in Taiwan from 1996 and 2013 were evaluated using data from the Taiwan Cancer Registry. The life-table method and the Cox proportional hazards analysis were used to evaluate the survival of gastric cancer.

RESULTS

The incidence of all gastric cancers in Taiwan decreased from 15.97 per 100,000 in 1996 to 11.57 per 100,000 in 2013. The most frequent histologic subtype of gastric cancer in Taiwan was adenocarcinoma, followed by lymphoma and sarcoma (mainly gastrointestinal stromal tumor). The best survival was in patients with sarcoma, followed by lymphoma, neuroendocrine tumor, and adenocarcinoma. Generally, women had a better survival than men. The incidence of adenocarcinoma significantly decreased from 13.56 per 100,000 in 1996 to 9.82 per 100,000 in 2013 (P < 0.0001). In contrast, the incidences of mucosa-associated lymphoid tissue lymphoma and diffuse large B-cell lymphoma did not decrease.

CONCLUSIONS

The incidence of adenocarcinoma and lymphoma, both of which are associated with H. pylori, showed diverging trends. The survival of gastric cancer differed by histologic subtype and sex.

IMPACT

The disparity in the incidence trends between gastric lymphoma and adenocarcinoma, both associated with H. pylori, warranted the need to search for additional risk factors of gastric lymphoma.

18F-Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography in mucosa-associated lymphoid tissue lymphoma: variation in 18F-FDG avidity according to site involvement

The purpose of this study was to determine the 18F-FDG avidity of MALT lymphoma and the additional utility of 18F-FDG PET/CT in MALT lymphoma staging. Pretreatment 18F-FDG PET/CT scans of 222 patients with 227 MALT lymphoma lesions were retrospectively analyzed. 18F-FDG avidity of lesions was noted in 28%. The proportion was lower for gastric MALT lymphomas than for non-gastric lesions (9% vs. 60%, p<0.0001) and higher for mass-forming lesions than for superficial lesions (82% vs. 2%, p<0.0001). 18F-FDG PET/CT showed the presence of additional lesions in 23 patients: four of six true-positive lesions had 18F-FDG avid primary lesions, and 15 of 17 false-positive lesions had 18F-FDG-non avid lesions. 18F-FDG avidity differed according to the location and gross morphologic characteristics of the MALT lymphoma. Most gastric MALT lymphomas were superficial and had low 18F-FDG avidity. For staging, 18F-FDG PET/CT can be helpful mainly for 18F-FDG avid primary MALT lymphomas.

The Influence of the Gut Microbiome on Obesity, Metabolic Syndrome and Gastrointestinal Disease

There is a fine balance in the mutual relationship between the intestinal microbiota and its mammalian host. It is thought that disruptions in this fine balance contribute/account for the pathogenesis of many diseases. Recently, the significance of the relationship between gut microbiota and its mammalian host in the pathogenesis of obesity and the metabolic syndrome has been demonstrated. Emerging data has linked intestinal dysbiosis to several gastrointestinal diseases including inflammatory bowel disease, irritable bowel syndrome, nonalcoholic fatty liver disease, and gastrointestinal malignancy. This article is intended to review the role of gut microbiota maintenance/alterations of gut microbiota as a significant factor as a significant factor discriminating between health and common diseases. Based on current available data, the role of microbial manipulation in disease management remains to be further defined and a focus for further clinical investigation.

Review article: common misconceptions in the management of Helicobacter pylori-associated gastric MALT-lymphoma

BACKGROUND

Helicobacter pylori infection is the main cause of gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

AIM

To review several common misconceptions in the management of H. pylori-associated gastric MALT-lymphoma.

METHODS

Bibliographical searches were performed in MEDLINE up to June 2011.

RESULTS

If adequate diagnostic methods are used, and if only low-grade lymphomas are considered, the prevalence of H. pylori infection is very high (almost 90%). H. pylori eradication is effective in treating approximately 80% of patients with early stage lymphoma. In H. pylori-positive gastric high-grade lymphomas, antibiotic therapy should always be prescribed, as approximately 50% of them regress after H. pylori eradication. Patients with early stage MALT lymphoma negative for H. pylori might still benefit from antibiotic treatment as the sole treatment. Complete remission of gastric MALT lymphoma after H. pylori eradication can take even >12 months. PCR assay for the detection of monoclonal B cells remains positive in many cases after complete remission has been reached. Patients with a persistent clonal band should not be treated unless the lymphoma can be histologically demonstrated. Synchronous occurrence of gastric adenocarcinoma and MALT lymphoma has been repeatedly reported. In some patients in complete remission, eradication of H. pylori does not prevent later development of early gastric cancer. Gastric lymphoma recurrence occurs in some patients after both bacterial and lymphoma regression. H. pylori reinfection does not constitute a prerequisite for lymphoma recurrence.

CONCLUSIONS

The present article states several misconceptions in the management of H. pylori-associated gastric MALT-lymphoma in clinical practice, reviews the related scientific evidence and proposes the adequate attitude in each case.

[Primary digestive tract lymphoma in central region of Tunisia: anatomoclinical study and therapeutic results about 153 cases]

Primary gastro-intestinal lymphoma (PGIL) is the most common type of extra-nodal non Hodgkin's lymphoma. Their clinical and histological presentations are heterogeneous depending on the site of the lesion. There is no consensus regarding the role of surgery and chemotherapy in the therapeutic approach. In our country epidemiology of the disease is unknown with IPSID being the most frequent type. We report anatomo-clinical features and prognostic factors of PGIL and compare intestinal to gastric forms in our region. This is a retrospective study of 153 cases of PGIL in adults diagnosed and treated in the department of medical oncology in Farhat Hached Hospital between 1994 and 2006. The median age was 52 years and the sex-ratio 2.1. Tumor sites were gastric (67%), intestinal (26%) and gastrointestinal (7%). Abdominal pain (87%) followed by vomiting and diarrhoea (37 and 15%) were the most common symptoms. Performance status (PS) < 2 was seen in 80% of patients, high grade lymphoma in 70.5% of cases and B phenotype was noted in 85%. MALT lymphoma accounts for 50% of cases, and IPSID for only 5% of PGIL. About 47.5% of cases were stage IE, 138 patients had chemotherapy with an objective response rate of 77%. Only 46% of patients had surgery (14 for surgical complication, 6 for residual tumor after chemotherapy and 22 to have histological diagnosis). The five-year overall survival (OS) was 62%. In high grade lymphoma patients favorable prognostic factors for OS included young age < or = 60 years, PS < 2, normal serum LDH, hemoglobin > 12 g/dL, B phenotype, localised stage (IE-IIE1), anthracycline-based chemotherapy regimen, achieving complete or partial response to induction chemotherapy and no relapse. In multivariate study only relapse and PS were significant prognostic factors for OS. In low-grade lymphoma patients, none of these factors had a significant correlation with OS: age < or = 60 years, PS < 2, stage (IE-IIE1), response to induction chemotherapy, relapse. Compared to gastric lymphomas, intestinal cases occurred at a younger age, frequently with diarrhoea, weight loss, and occlusion. They are more often high-grade, T phenotype and have locally advanced stage (IIE); surgery is more common in this group. We conclude that stomach is the main site of PGIL in our region, intestinal lymphoma is less frequent and IPSID has become rare. Recent progress in chemotherapy has allowed good therapeutic results with a conservative approach. Surgery may be performed in case of emergency or for residual lesions after medical treatment.

Mycosis fungoides and Sézary syndrome

Mycosis fungoides and Sézary syndrome are the most common of the cutaneous T-cell lymphomas, which are a heterogeneous group of neoplasms that affect the skin as a primary site. Although the aetiologies of mycosis fungoides and Sézary syndrome are unknown, important insights have been gained in the immunological and genetic perturbations that are associated with these diseases. Unlike some B-cell lymphomas, cutaneous T-cell lymphomas as a group are rarely if ever curable and hence need chronic-disease management. New approaches to treatments are being investigated and include biological and cytotoxic drugs, phototherapy, and monoclonal antibodies that are directed towards novel molecular targets. New molecular technologies such as complementary-DNA microarray have the potential to increase the accuracy of diagnosis and provide important prognostic information. Treatments can be combined to greatly improve clinical outcome without substantially increasing toxic effects in advanced disease that is otherwise difficult to treat. Although present treatment strategies are generally not curative, there is hope that experimental treatments, particularly immunotherapy, might eventually reverse or suppress the abnormalities of mycosis fungoides and Sézary syndrome to the point at which they become non-life-threatening, chronic diseases.

Synchronous Mucosa-Associated Lymphoid Tissue Lymphoma and Gastrointestinal Stromal Tumor of the Stomach Presenting with Gastric Bleeding

We report an extraordinarily rare case of synchronous mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor of the stomach. An 80-year-old man presented with gastric bleeding. Gastroscopy showed an ulcerative lesion and a submucosal tumor at the upper corpus of the stomach. The ulcerative lesion was proven by biopsy to be mucosa-associated lymphoid tissue lymphoma, but the submucosal tumor could not be diagnosed. Due to the repeating episodes of massive gastric bleeding, a total gastrectomy with lymphadenectomy was performed. After the operation, the submucosal tumor was pathologically proven to be a gastrointestinal stromal tumor. In this case, synchronous occurrence of mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor seems to be coincidental rather than related with the same pathogenic triggering. Surgical resection of the stomach provided an accurate diagnosis and an effective treatment.

The value of EUS in predicting the response of gastric mucosa-associated lymphoid tissue lymphoma to Helicobacter pylori eradication

BACKGROUND

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is associated with Helicobacter pylori infection, and regression of the tumor has been described after its eradication.

OBJECTIVE

To determine the value of EUS, in addition to other clinical/endoscopic features, in predicting the response of low-grade MALT lymphoma to H pylori eradication.

DESIGN

A retrospective, single-center study.

SETTING AND PATIENTS

Twenty-two patients with primary gastric MALT lymphoma were identified through a retrospective review of charts of patients seen at the American University of Beirut Medical Center. Only 19 patients with histopathologically confirmed gastric MALT lymphoma and H pylori infection who had EUS staging were included in the study.

MAIN OUTCOME MEASUREMENTS

Regression of the gastric MALT lymphoma as determined by follow-up endoscopy and mucosal biopsies.

RESULTS

Patients with disease restricted to the gastric mucosa had a significantly higher rate of complete remission after H pylori eradication compared with patients who had disease infiltrating into the gastric submucosa (77.8% vs 12.5%, P value .007). There was no statistical difference in terms of the mean follow-up time to achieve such response (P value .212). Age, sex, location of the tumor within the stomach, and endoscopic appearance did not correlate with the probability of complete remission of the MALT lymphoma.

LIMITATIONS

The limitations include a retrospective design and a relatively small sample population.

CONCLUSION

EUS determination of the invasion depth of gastric MALT lymphoma helps predict a complete response to H pylori eradication.

Primary gastric lymphoma in Jordan with special emphasis on descriptive epidemiology

The aim of this study was to examine the clinicopathological features and epidemiology of primary gastric lymphoma in Jordan as a model for Middle East countries where such data is scarce. From 1991--2002, 219 patients with primary gastric malignancy were managed at our hospitals. Among these there were 19 patients with primary gastric lymphoma. Pertinent data for these patients were analyzed. Primary gastric lymphoma constituted 65.5% of all gastrointestinal lymphoma and 8.7% of all gastric malignancies. Male-to-female ratio was 2.8:1. The mean age was 56 years (range 39--82). The incidence was 0.6/100,000. The proximal third was the most common localisation. Abdominal pain was the commonest presentation. Low-grade MALT lymphomas, high-grade MALT lymphomas, diffuse large cell B lymphomas and T cell lymphoma were found in 21.1, 26.3, 47.4 and 5.3%, respectively. Nine patients had gastrectomy followed by chemotherapy, 6 patients had palliative resection, 3 patients had chemotherapy only and the remaining patient was treated with Helicobacter pylori eradication. The mean follow-up for all patients was 42.2 months. The 5-year survival rates for stages IE (n=5), IIE (n=4), IIIE (n=6) and IVE (n=4) were 100, 67, 27 and 0%, respectively (p=0.0003). The overall 5 years survival was 48.2%. Primary gastric lymphoma in Jordan shares some epidemiological features with western disease. Jordanian patients are detected and treated after a relatively long delay. Advanced stage at diagnosis correlated with poor outcome. There is a need of an earlier diagnosis and subsequent better care.

One-year follow-up study of Helicobacter pylori eradication rate with 13C-urea breath test after 3-d and 7-d rabeprazole-based triple therapy

AIM: To investigate the long-term role of a 3-d rabeprazole-based triple therapy in patients with Helicobacter pylori(H pylori)-infected active peptic ulcers.

METHODS: We prospectively studied 115 consecutive patients with H pylori-infected active peptic ulcers. H pylori infection was confirmed if any two of H pylori DNA, histology, and rapid urease test were positive. Patients were assigned to either an open-labeled 3-d course of oral amoxicillin 1000 mg b.i.d., clarithromycin 500 mg b.i.d., and rabeprazole 20 mg b.i.d., or 7-d course of oral amoxicillin 1000 mg b.i.d., clarithromycin 500 mg b.i.d., and rabeprazole 20 mg b.i.d. Subsequently, all patients received oral rabeprazole 20 mg once daily until the 8^th wk. Three months after therapy, all patients were followed-up endoscopically for the peptic ulcer, H pylori DNA, histology, and rapid urease test. One year after therapy, H pylori infection was tested using the ¹³C-urea breath test.

RESULTS: The ulcer healing rates 3 mo after therapy were 81.0% vs 75.4% for the 3-d and 7-d groups [intention-to-treat (ITT) analysis, P = 0.47] respectively, and 90.4% vs 89.6% for the 3-d and 7-d groups [per-protocol (PP) analysis, P = 0.89] respectively. The eradication rates 3 mo after therapy were 75.9% vs 73.7% for the 3-d and 7-d groups (ITT, P = 0.79) respectively, and 84.6% vs 87.5% for the 3-d and 7-d groups (PP, P = 0.68) respectively. One year after therapy, seventy-five patients returned to receive the ¹³C-urea breath test, and the eradication rates were 78.4% vs 81.6% in 3-d and 7-d groups (PP, P = 0.73) respectively.

CONCLUSION: Our study showed the eradication rates against H pylori infection 3 and 12 mo after triple therapy were not different between the 3-d and 7-d rabeprazole-based groups. Therefore, the 3-d rabeprazole-based triple therapy may be an alternative treatment for peptic ulcers with H pylori infection.

Lymphome oculaire de type MALT simulant une sclérite ou une uvéite postérieure

PURPOSE

Diagnostic and therapeutic management of masquerade syndromes associated with MALT-type lymphoma.

PATIENTS AND METHOD

We report the cases of three patients referred for acute or chronic severe loss of visual acuity. All of them suffered from uveitis or scleritis resistant to corticoid treatment. Each one had posterior uveitis associated with retinochoroidal infiltration, anterior scleritis associated with uveal effusion syndrome, or bilateral pan-uveitis associated with serous retinal detachment. Two patients had medical records of systemic malignancies. They underwent an extensive work-up. Search for an infectious, immune or malignant disease was negative but orbital imaging showed a posterior scleral thickening in all cases.

RESULTS

Diagnosis of mucosa-associated lymphoid tissue (MALT) ocular lymphoma was assessed in all cases after scleral biopsy. Immunohistochemical analysis showed CD20(+) and CD5(-) scleral lymphocyte infiltrates. The three patients underwent chemotherapy associated with radiotherapy. Lesions were stabilized in the first case, whereas six lines of visual acuity improvement was noted in the second one, and full recovery was achieved after treatment in the third case.

DISCUSSION

Clinical manifestations of this ocular lesion seem to be multiple, masquerading as different types of posterior uveitis or scleritis. In the three cases, we did found other systemic locations of MALT-type lymphoma. Diagnosis was mainly based on pathological analysis. Fast visual recovery in two cases demonstrated the importance of an early diagnosis and a specific treatment. All cases of chronic and corticoid-resistant posterior uveitis require a specialized radiological evaluation followed, if necessary, by multiple orbital biopsies.

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma in gastroscopic biopsy

AIM: To explore and discuss the clinicopathologic characteristics of mucosa-associated lymphoid tissue (MALT) lymphoma in gastroscopic biopsy specimen.

METHODS: A retrospective study of 26 cases of lymphoma diagnosed by gastroscopic biopsy during 1999 to 2001 from gastroscopy files of Xijing Hospital was made. The diagnostic criteria were adopted according to the new classification of non-Hodgkin's lymphoma.

RESULTS: Twenty-six cases of primary gastric lymphoma consisting of 15 men and 11 women, aged between 23 to 76 years were recruited from 6225 cases who received gastroscopy. All of them were diagnosed by both endoscopic findings and histological examinations. Histologically, 23 cases were MALToma (low grade) and 3 cases lymphoblastic lymphoma (high grade). Immunohistochemically, all cases were CD20 positive, while CK and EMA were negative.

CONCLUSION: The majority of the cases of primary low-grade gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa associated lymphoid tissue.

Clinicopathologic and immunohistochemical study of surgically treated primary gastric MALT lymphoma

BACKGROUND AND OBJECTIVES

B-cell MALT lymphoma is a well-recognized entity and its characterization as low-grade (LG) and high-grade (HG) lymphoma has been widely accepted. In the present study we reviewed a series of 95 surgical specimens of primary gastric MALT lymphoma selected between 1979 and 1998. Immunohistochemical expression of p53, bcl-2, and Ki67 and Helicobacter pylori (Hp) infection was evaluated, along with a correlation with clinical outcome.

METHODS

A morphologic and immunohistochemical analysis, including p53, bcl-2, and Ki67 expression, was carried out in all cases. A complete follow-up was obtained in 49 patients and in these cases a survival analysis was performed.

RESULTS

bcl-2 protein was highly expressed in 25 of 25 assessed LG tumors and in 20 of 24 assessed HG tumors. p53 protein was expressed in 13 of 25 assessed LG tumors and in 21 of 24 assessed HG tumors. High proliferation rate as expressed by Ki67 was detected in 15 of 25 assessed LG tumors and in 23 of 24 assessed HG tumors. Hp infection was detected in 11 of 16 assessed LG tumors and 2 of 10 assessed HG tumors. Median survival rates were 72 months for LG tumors and 24 months for HG tumors.

CONCLUSIONS

A significant inverse relationship between Hp infection and histological grade was found. High p53 expression and high-proliferation rate correlated with HG tumors. However, a correlation between p53, bcl-2, and Ki67 expression with clinical outcome was not found.

Two-year follow-up of Helicobacter pylori infection in C57BL/6 and Balb/cA mice

Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. We previously found high-grade lymphoma after 13 months' H. pylori infection in C57BL/6 mice. In this study we followed H. pylori infection by three different isolates in C57BL/6 and Balb/cA mice for 23 months. Six-week-old C57BL/6 and Balb/cA mice were infected with H. pylori strains 119p (CagA+, VacA+), SS1 (CagA+, VacA+) and G50 (CagA-, VacA-). Mice were followed at 2 weeks, 10 weeks and 23 months post-inoculation (p.i.) by culture, histopathology and serology. Strain G50 was only reisolated from mice 2 weeks p.i. There was no difference in colonization between strain 119p and SS1 at 10 weeks p.i., whereas SS1 gave 100% colonization versus 119p gave 50% 23 months p.i. Interestingly, the inflammation score was higher in mice infected with strain 119p than with SS1 10-week p.i., and there were lymphoepithelial lesions in mice infected with strain 119p and G50 but not with SS1 at 23 months post-infection. Eight mice infected with strains 119p and G50 developed gastric lymphoma (grade 5 and 4). One C57BL/6 mouse infected with strain 119p developed hepatocellular carcinoma after 23 months. Immunoblot showed specific bands of 26-33 kDa against H. pylori in infected mice, and two mice infected with strain SSI reacted with antibodies to the 120 kDa CagA toxin.

CONCLUSION

A reproducible animal model for H. pylori-induced lymphoma and possibly hepatocellular carcinoma is described. Strain diversity may lead to different outcomes of H. pylori infection.

MUC1 mucin expression in follicular dendritic cells and lymphoepithelial lesions of gastric mucosa-associated lymphoid tissue lymphoma

Membrane-associated mucin MUC1 is expressed in various adenocarcinoma cells and active T lymphocytes. We tried to find out whether MUC1 is expressed in gastric mucosa-associated lymphoid tissue (MALT) lymphoma lesion. MUC1 was not expressed in infiltrating T lymphocytes; however, MUC1 was found on the cell surface of follicular dendritic cells (FDC) of germinal centers and in the epithelial cytoplasm of lymphoepithelial lesion (LEL) of the lymphoma, which were immunohistochemically detected by monoclonal antibodies DF3 and MY.1E12. MUC1 was also expressed in the FDC of control cases (gastrectomy specimen containing reactive lymphoid follicles, n = 10, MUC1/ DF3, 100%; MUC1/MY.1E12, 40%), and FDC in MALT lymphomas (n = 59) showed lower MUC1 expression rates (MUC1/ DF3, 32%; MUC1/MY.1E12, 0%) than the control (P < 0.001). Lymphoepithelial lesion in the low-grade MALT lymphomas (n = 23) showed a higher MUC1/DF3 expression rate (30%) than those in the high-grade MALT lymphomas (n = 36; 6%; P < 0.05). T lymphocytes in the surface mucosa were more frequent in MALT lymphoma (91.4 +/- 80.6/unit area) than those in the control (20.0 +/- 23.6) (P < 0.001). S100-positive dendritic cells around LEL were more frequent in the low-grade (19.0 +/- 9.4/unit area) than in the high-grade (11.7 +/- 9.7) (P < 0.005). This study demonstrated MUC1 mucin expression on FDC for the first time. Mucosa-associated lymphoid tissue lymphoma, especially low-grade, shows immunologically active state, where FDC MUC1 expression may be suppressed by some factors released from lymphoma cells. Further study to elucidate the pathogenetic role of MUC1 in MALT lymphoma is necessary.

The natural history of a gastric low grade B cell MALT lymphoma followed during 11 years without treatment

Low grade B cell mucosa associated lymphoid tissue (MALT) lymphoma of the stomach is usually an indolent tumour that remains localised for a long time before dissemination occurs. MALT appears in the stomach in response to infection by Helicobacter pylori, which is present in 80-90% of cases. The pathogenesis of the evolution from chronic gastritis to malignant lymphoma has not yet been fully explained and the exact role of H pylori in the pathogenesis and progression of gastric lymphoma remains unclear. This report describes the case of a 72 year old woman with a low grade B cell MALT lymphoma localised in the gastric fundus, who refused to be treated for eradication of H pylori. The histological diagnosis of B cell MALT lymphoma was supported by both immunohistochemical and molecular genetic analysis. After 11 years of follow up, this MALT lymphoma remained indolent, without local progression or blastic transformation, and the H pylori infection was still persistent, even though the density of bacteria had decreased drastically. Interestingly, two different clonal immunoglobulin (Ig) gene rearrangements were found in two series of biopsies performed with an interval of 11 years. This case report supports the following notions: (1) H pylori associated gastritis is a risk factor for gastric MALT lymphoma, but might not be sufficient by itself for the progression of the disease, and (2) in the evolution of MALT lymphomas, different cell clones characterised by different Ig rearrangements may emerge.

Incidence of gastric B-cell lymphomas: a population-based study in Germany

BACKGROUND

While the clinical and experimental knowledge concerning gastric lymphomas is increasing, there is a scarcity of epidemiological data.

PATIENTS AND METHODS

A population-based sample of patients in Franconia and Saarland in Germany was collected from a clinical trial, hospital archives and a cancer registry.

RESULTS

Over a period of 3 years, 94 patients with primary gastric lymphoma were recorded out of a total population of 3.5 million. The standardised incidence rates in Saarland and Franconia were 0.7 and 0.8 cases per 100 000, respectively. Patients were predominantly from higher age groups (mean age 62.1 years) and the incidence in men was slightly more than in women (P <0.03). The distribution of histological subtypes in Franconia was as follows: marginal zone B-cell lymphomas (MZBL), 58%; diffuse large-cell B-cell lymphoma (DLBL), 33%; and mixed forms, 9%. Helicobacter pylori could be detected histologically in 84% of all cases, 95% of MZBL cases and 68% of DLBL cases.

CONCLUSIONS

Incidence rates of gastric lymphoma in Germany were similar to that in other European countries, except England, where rates are lower. The subtype-specific differences of H. pylori infection rates could be due to differences in carcinogenesis or to secondary changes during malignant transformation.

High frequency of MALT lymphoma in a series of 14 cases of primary breast lymphoma

This article reports the clinicopathologic and immunohistochemical findings of 14 cases fulfilling the criteria of Wiseman and Liao for primary lymphoma of the breast (PBL), with emphasis on the frequency of mucosa-associated lymphoid tissue (MALT) lymphomas. The tumors were reclassified according to the revised European-American classification of lymphoid neoplasms. Immunohistochemistry was used to assist in the classification and subtyping of PBL, to demonstrate lymphoepithelial lesions (LEL), and to assess estrogen/progesterone receptor expression. Nine tumors were classified as MALT lymphomas (seven low grade and two high grade), four as diffuse large cell lymphomas and one as follicle center lymphoma. Extensive lymphoid cell infiltration of mammary ducts and acini was also found in non-MALT lymphoma cases. None of the 14 cases expressed hormonal receptors. Primary lymphoma of the breast is a rare and morphologically heterogeneous entity. There is similarity on the clinicopathologic overall profile of the current series of patients and those previously reported, but we recorded a higher incidence of MALT lymphoma (64.3%). Immunohistochemistry is mandatory to identify "true" LEL because epithelial permeation by lymphoid cells can also be found in non MALT-type lymphomas.

Helicobacter pylori infection in children

A number of scientific breakthroughs since H pylori first became recognized as a human pathogen have increased our understanding of the pathogenesis of gastroduodenal disease. In particular, advances in molecular bacteriology and the complete sequencing of the H pylori genome in 1999, and soon thereafter the human genome, provide tools allowing better delineation of the pathogenesis of disease. These molecular tools for both bacteria and host should now be applied to multicenter pediatric studies that evaluate disease outcome. More recent developments indicate that a better understanding of the microbial-host interaction is critical to furthering knowledge with respect to H pylori-induced diseases. Studies are needed to evaluate either DNA-based or more traditional protein-based vaccines, to evaluate more specific antimicrobials that confer minimal resistance, and to evaluate probiotics for the management of H pylori infection. Multicenter multinational studies of H pylori infection in the pediatric population, which include specific, randomized controlled eradication trials, are essential to extend current knowledge and develop better predictors of disease outcome.

A critical review of the effect of Helicobacter pylori eradication on gastric MALT lymphoma

Low-grade B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) are thought to arise within organized lymphoid tissue in the gastric mucosa that is most frequently acquired in response to Helicobacter pylori infection. This close association between the organism and the lymphoma is further reflected by the demonstration that the proliferation of the lymphoma cells can be driven by the presence of H. pylori organisms through a complex path of cellular interactions involving specific T cells. From these observations it was suggested that removal of one of the proliferative drives to the neoplastic cells in the form of eradication of the organism might induce a remission in the tumor. Several large multicenter studies are now underway to consider this question, and interim reports suggest that long-term remissions can be induced in low-grade MALT lymphomas in 70% to 80% of cases. The lymphomas that are most likely to respond to H. pylori eradication are those that are located superficially within the gastric mucosa. It has been suggested that certain genetic abnormalities, such as t(11;18) and the Bcl-10 mutation, may be associated with lack of response to this therapy. Recurrences of low-grade lymphoma are encountered in patients treated by H. pylori eradication, but these appear to be infrequent and may be self-limiting and spontaneously regress without further therapy.

Helicobacter pylori-gastrin link in MALT lymphoma

BACKGROUND

There is accumulating evidence for the role of Helicobacter pylori in the development of gastric cancer as well as of lymphomas that arise in mucosa-associated lymphoid tissue (MALT). We reported recently that gastric cancer patients show high prevalence of cagA-positive H. pylori and express gastrin and gastrin receptors enabling them to stimulate tumour growth in autocrine fashion.

AIMS

Since the H. pylori infection is considered to be more strongly associated with MALT lymphoma than with gastric cancer, we decided to determine the gastrin and its receptors' mRNA expression and gastrin content in this tumour as well as the release of this hormone both into plasma and gastric lumen. Twenty MALT lymphoma patients were compared with 100 age- and gender-matched controls with similar dyspeptic symptoms.

RESULTS

The overall H. pylori seropositivity in MALT lymphoma was about 90% and CagA positivity was 70%, compared to 56% and 33%, respectively, in controls. The serum gastrin in MALT lymphoma was about sixfold higher than in controls while gastric luminal gastrin in these patients was over 70 times higher than in controls. Gastrin content in tumour was about 10-fold higher than in antral mucosa. Gastrin and gastrin-receptor (CCKB-receptor) mRNA were detected by reverse transcriptase-polymerase chain reaction in cancer tissue whilst in the fundic and antral mucosa, only enhanced expression of CCKB-receptor mRNA and gastrin mRNA was detected, respectively. Histamine stimulation in MALT lymphoma induced acid secretion that was only about 30% of control value due to atrophic gastritis. This study confirms an important role of CagA-positive H. pylori in the pathogenesis of MALT lymphoma and shows that this lymphoma is capable of synthesizing and releasing potent growth promoting gastrin, possibly due to the action on G-cells of H. pylori-originated Nalpha-methyl histamine and cytokines (tumour necrosis factor alpha and interleukin-8).

CONCLUSIONS

Gastric MALT lymphoma is closely linked to CagA-positive H. pylori infection. Gastrin and its receptors may be implicated in the pathogenesis of gastric lymphoma.

Helicobacter pylori infection and gastrin and cyclooxygenase expression in gastric and colorectal malignancies

Helicobacter pylori, infecting more than 50% of the world population, results in gastritis, usually located in the antral portion of the stomach, accompanied by hypergastrinemia, the key factor in gastric and colorectal carcinogenesis. Excessive mucosal cell proliferation for many years may eventually result in gastric atrophy, cell mutation and transformation of gastric mucosal cells into gastrin-producing cells, which also express gastrin receptors serving to stimulate cell proliferation and tumor growth. These processes may be completed by the expression of cyclooxygenase-2 (COX-2) as an inflammation enzyme to release excessive amounts of PGE(2), leading to further proliferation, reduction in apoptosis, angiogenesis and tumor growth. H. pylori eradication results in complete regression of MALT lymphoma and subsequent normalisation of excessive gastrin release and COX-2 expression. Reduction of gastrin by active immunisation (gastrimmune), blocking of gastrin receptors with specific blockers and suppression of COX-2 might be helpful in inhibiting tumor growth and invasion.

Epidemiology of lymphomas

Non-Hodgkin lymphoma (NHL) is the fifth most common cancer in the US, with about 55,000 new cases estimated for the year 2000. According to the new Surveillance, Epidemiology, and End Results (SEER) data from 1973 to 1997, the age-adjusted incidence rates rose by about 80%, with an annual percentage increase of nearly 3%, which is faster than for the majority of cancers. The increasing incidence of NHL is largely unexplained. AIDS-related NHL accounts for some but not all of the increase. The American Cancer Society predicts about 7,400 new cases of Hodgkin Disease (HD) in the year 2000 in the US. The incidence of HD is consistently lower than that of NHL, and has decreased about 16% since the 1970s. Only a small portion of the decrease in HD incidence can be explained by misdiagnosis of HD as NHL. Further research is needed on the cofactors that predispose AIDS cases to lymphoma, as well as other possible causes of NHL such as immunosuppression, genetics, viruses, medical conditions, pesticides, solvents, hair dyes, and diet. Further evaluation of the role of viruses, occupational exposures, and genetics in the etiology of HD should prove valuable.

A reassessment of primary thyroid lymphoma: high-grade MALT-type lymphoma as a distinct subtype of diffuse large B-cell lymphoma

AIMS

Primary lymphoma of the thyroid gland (PTL) is a relatively rare disease. During an 18-year period, 53 cases of primary non-Hodgkin's lymphoma involving this extranodal site were seen at our institutions. The aims of this study were to evaluate the spectrum of PTLs using current lymphoma classification concepts and immunocytochemical markers, determine whether features of MALT-type lymphoma were evident in PTL, and if there was any clinical significance of such a finding.

METHODS AND RESULTS

The cases were retrospectively studied clinically, histologically and immunohistochemically. The tumours were classified according to the Revised European-American Lymphoma Classification of lymphoid malignancies (REAL classification). Thirty-eight patients were females, 15 were males and mean age at diagnosis was 66.3 years (range 38-90). Three cases were low-grade marginal zone lymphomas (low-grade MALT-type lymphomas). There were 45 diffuse large B-cell lymphomas (DLBCL) of which there were 27 DLBCL-NOS and 18 high-grade MALT-type lymphomas. Within the diffuse large B-cell lymphoma (DLBCL) category, cases were subdivided into those without (DLBCL-NOS) and those with features of 'high-grade' MALT-type lymphoma based on presence of a low-grade component or large cell lymphoepithelial lesions (HG MALT-type lymphoma). In addition there were three follicle centre lymphomas, one anaplastic large cell lymphoma and one peripheral T-cell lymphoma. Twenty cases were stage IE, 18 stage IIE, and four stage IV. All patients with low-grade MALT-type lymphoma are alive without disease. The 5-year survivals for DLBCL-NOS and HG MALT-type lymphoma were 75% and 25%, respectively. Univariate analysis (log rank) among the DLBCLs showed stage (P < 0.001) and subtype (P = 0.005) were associated with survival. Stage was associated with type of DLBCL, 65% of DLBCL-NOS being stage IE compared to 20% of HG MALT-type lymphomas.

CONCLUSIONS

We conclude that primary thyroid lymphomas occur most commonly in elderly women and are frequently present in clinical stage IE and IIE. Low-grade MALT-type lymphomas are relatively uncommon but appear to have a favourable prognosis. DLBCL is the most common lymphoma and features of MALT can be seen in over one-third of cases. As a group, HG MALT-type lymphomas had a worse outcome than DLBCL-NOS, primarily due to higher clinical stage at diagnosis. These two subtypes of DLBCL appear to be distinct clinical and histological entities.

Association between Helicobacter pylori cytotoxic type I CagA-positive strains and migraine with aura

Recent studies have suggested an association between Helicobacter pylori infection and migraine. However, various strains of the bacterium are present, some endowed with greater pathogenicity. In particular, H. pylori type I CagA-positive strains induce a higher release of proinflammatory substances by the gastric mucosa that could trigger systemic vasospasms. The aim of the present study was to assess the prevalence of H. pylori CagA-positive strains in subjects with migraine. One hundred and seventy-five patients affected by migraine (49 with aura, 126 without aura) were consecutively enrolled and matched for sex, age, social background and geographical origin with 152 controls. Helicobacter pylori infection was assessed through 13C-urea breath test. Specific serological IgG against CagA were detected through ELISA. The prevalence of H. pylori infection was similar in migraine patients and in controls (40% vs. 39%, respectively). Among migraine patients, prevalence of infection was not related to presence or absence of aura (45% vs. 37%, respectively). However, among infected subjects, a significantly higher prevalence of CagA-positive strains was observed in patients affected by migraine with aura when compared with those affected by migraine without aura (41% vs. 19%, P < 0.01) and with controls (41% vs. 17%, P < 0.01). CagA-positive H. pylori strains were found to be strongly associated with migraine with aura. A higher inflammatory response of the gastric mucosa to more virulent strains could release substances that may act as triggers of vasospasm in peculiar cerebral arterial districts, probably implicated in the 'aura' phenomenon.

The product of the t(11;18), an API2-MLT fusion, is an almost exclusive finding in marginal zone cell lymphoma of extranodal MALT-type

BACKGROUND

Extranodal marginal zone cell lymphoma (MZCL) of MALT-type share similar features with nodal and splenic MZCL regarding morphology and immunophenotype. At the genetic level, recent cytogenetic studies have shown that t(11;18) is a recurring abnormality in extranodal MALT-type MZCL but has hitherto never been reported in nodal or splenic MZCL. The aim of the present study was to determine the prevalence of t(11;18) in a large series of nodal, splenic and extranodal MALT-type MZCL, using a sensitive real-time RT-PCR method.

MATERIALS AND METHODS

Ninety-three MZCL cases were divided on clinical grounds into 61 extranodal MALT-type, 19 splenic and 12 nodal MZCL. One case that presented with a massive splenomegaly but for which also gastro-intestinal localisations were found, was left unclassified. A real-time RT-PCR method for the detection of the API2-MLT fusion resulting from t(11;18) was performed on RNA extracted from frozen tissue sections.

RESULTS

The API2-MLT fusion was detected in 12 cases, which were all extranodal MALT-type lymphomas of the stomach, except for one case. The remaining positive case was the unclassified case, for which the translocation was detected in the spleen and in hilar lymph node tissue.

CONCLUSIONS

While similarities between MZCL from different anatomic sites have lend us to propose that all MZCL have a common normal counterpart, the almost exclusive detection of t(11;18) in gastric MALT-type lymphoma favours its recognition as a separate lymphoma entity. The absence of the translocation in nodal and splenic MZCL challenges the idea of these lymphomas being secondary to MALT-type lymphomas of the gut. The unclassified case illustrates the inadequate approaches available at present to identify and define the various MZCL.

Low-grade MALT lymphoma of the stomach: a review of treatment options

PURPOSE

Low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach (MLS) is often associated with the presence of Helicobacter pylori (H. pylori) bacteria. Eradication of the infection with antibiotic therapy may result in regression of the lymphoma. But when antibiotic treatment fails to reverse the malignant process or if H. pylori is absent, other treatment options should be considered. Because MLS is often confined to the stomach and regional lymph nodes, it is potentially curable with local therapy. Endoscopy and improved imaging, with endoscopic ultrasound (EUS) and computerized tomography (CT), have reduced the prior dependence on surgery for diagnosis and staging of gastric lymphomas.

METHODS AND RESULTS

This review details the advances in the diagnosis, classification, and imaging of MLS. We also describe the experience that supports the use of radiation therapy as the preferred treatment of MLS in patients who have not responded to antibiotic therapy or have not had evidence for H. pylori infection.

CONCLUSIONS

Radiation therapy for MLS is not only effective and safe, but offers the significant advantage of low morbidity and gastric function preservation.