Gastric mucosa-associated lymphoid tissue lymphoma

Confocal laser endomicroscopy diagnosis of gastric adenocarcinoma in a patient treated for gastric diffuse large-B-cell lymphoma

The association between gastric carcinoma and lymphoma is rare. Confocal laser endomicroscopy is a new diagnostic tool that allows the identification of cellular and vascular architecture during endoscopy. This is the first report of an in vivo early gastric carcinoma diagnosis by confocal laser endomicroscopy in a patient successfully treated for a primary gastric diffuse large-B-cell lymphoma.

Mucosa-associated lymphoid tissue lymphoma presenting as massive gastrointestinal bleeding: a case report

We present a 71-year-old man with mucosa-associated lymphoid tissue (MALT) lymphoma of the colon presenting with massive gastrointestinal hemorrhage. At laparotomy two areas of irregular mucosa were noted in the ascending colon and cecum. Pathology revealed MALT lymphoma. MALT lymphoma of the colon is rare and the presentation as well as outcome of our case makes him unique.

Endoscopic diagnosis and staging of mucosa-associated lymphoid tissue lymphoma

PURPOSE OF REVIEW

The role of endoscopy, including endoscopic ultrasound, in the diagnosis and management of mucosa-associated lymphoid tissue lymphomas of the stomach has evolved steadily in the last two decades. The present review summarizes recent findings and puts them in context with studies on the diagnosis and management of mucosa-associated lymphoid tissue lymphoma published earlier.

RECENT FINDINGS

Several recent studies have emphasized the crucial role of endoscopic ultrasound in treatment planning in patients with gastric mucosa-associated lymphoid tissue lymphoma. This is important as early-stage gastric mucosa-associated lymphoid tissue lymphomas can be managed just by the eradication of Helicobacter pylori by appropriate antibiotic regimens. However, the more advanced lesions are treated with much more invasive treatment regimens involving radical gastrectomy, chemotherapy or radiation, or all.

SUMMARY

Endoscopic ultrasound staging is highly accurate in predicting response to Helicobacter pylori eradication in patients with gastric mucosa-associated lymphoid tissue lymphoma. Normalization of gastric wall thickness and architecture can be used to monitor tumor regression following treatment. Endoscopic ultrasound findings can also be used to identify treatment failures and relapses and can help identify patients who need more aggressive therapy.

Changing epidemiology and risk factors for gastrointestinal non-Hodgkin's lymphoma in a North American population: population-based study

OBJECTIVES

To assess the incidence, risk factors, and endoscopic presentation of gastrointestinal non-Hodgkin's lymphoma (GI NHL) in a large predominantly urban adult population sample.

METHODS

A comprehensive database review of all diagnoses of GI NHL in the Calgary Health Region over a 5-yr period (1999-2003) was undertaken. Longer-term data from a population-based HIV database (1985-2004) were also reviewed. A regional pathology database was used to corroborate case identification. All patients 18 yr of age or older were included. Age- and gender-adjusted incidence rates were calculated. Within the HIV-positive population, incidence rates were compared over time. Endoscopic appearances were assessed and compared.

RESULTS

Fifty-six GI NHL cases occurred during the study period. The age- and gender-adjusted annual incidence of GI NHL was 1.73 per 100,000 in the study population. The majority were diffuse large B-cell histology (54%), followed by lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) (29%). Increasing age, history of kidney transplant, and H. pylori positivity in MALT lymphoma were identified as risk factors. Within the HIV-positive population, a highly significant drop in GI NHL was seen over time, with an incidence of 3.86 per 1,000 patient-years in 1985-1989 compared to zero cases in 2000-2004, despite a greater prevalence of HIV disease (P < 0.0001 for trend). MALT lymphoma was less likely to manifest as a mass on endoscopy versus other presentations (P < 0.05).

CONCLUSIONS

Population-based GI NHL incidence rates in Calgary are higher than those described elsewhere in North America or in Britain. The incidence of GI NHL within the HIV population has virtually disappeared, presumably due to the advent of highly active retroviral therapy.

Modulation of lymphocyte proliferation induced by gastric MALT lymphoma-associated Helicobacter pylori strains

BACKGROUND

Helicobacter pylori infection leads to different chronic diseases, suggesting that this bacterium can evade the host immune defense system. The ability to control lymphocyte proliferation may be a mechanism leading to the development of gastric pathologies. Our aim was to characterize the effects of mucosa-associated lymphoid tissue (MALT) associated H. pylori strains on lymphocyte proliferation.

MATERIALS AND METHODS

We measured the in vitro proliferation of human lymphocytes originally from blood or tonsil samples in the presence or absence of viable bacteria or lysates.

RESULTS

We showed that MALT lymphoma-associated strains are not likely to be directly responsible for anarchical B-cell proliferation in vitro. On the other hand, proliferation of prestimulated T lymphocytes was abolished in vitro by the presence of all H. pylori strains, whether associated with MALT lymphoma or not.

CONCLUSION

Inhibition of T-cell proliferation may be of major importance in the gastric colonization and in the persistence of the infection. Furthermore, this inhibition may favor anarchical B-cell proliferation in vivo and predispose the host to gastric MALT lymphoma, whereas MALT-associated H. pylori strains do not appear to possess a specific capability to directly stimulate B-lymphocyte proliferation.

Prevalence and risk factors for Helicobacter pylori infection in Chinese populations

BACKGROUND

The prevalence of Helicobacter pylori is higher in developing countries. The aim of this study was to investigate the prevalence and risk factors of H. pylori infection in areas with high prevalence of gastric cancer in Jiangsu Province, China.

METHODS

A prospective epidemiologic survey of H. pylori infection was accomplished in a natural population of 1457 individuals in Xiangshui and Gaoyou counties, Jiangsu Province, China. Questionnaires and laboratory tests for H. pylori infection ((13)C-urea breath test and serum IgG antibodies to H. pylori) were used and performed, respectively.

RESULT

Among 1371 subjects who completed questionnaires and H. pylori detection, 851 (62%) were H. pylori positive. The prevalence reached a peak at the age of 30-40 years (67%). There was no sex difference. The annual family income level was shown to be positively correlated with the risk of H. pylori infection. The prevalence of H. pylori infection was also associated with family size, education level, and several diet-related factors, such as the number of times cooked rice and potatoes eaten per week, and a family history of stomach diseases. Compared to nonsymptomatic individuals, people with dyspeptic symptoms (nausea, vomiting, and belching) presented a low prevalence of H. pylori infection. No association between H. pylori prevalence and smoking or drinking was found. Using multivariate logistic regression analysis, annual family income and education level were the independent predictors for H. pylori infection.

CONCLUSION

High prevalence of H. pylori infection was found in areas with a high risk of gastric cancer and was related to several risk factors. The underlying mechanisms need to be further investigated.

Helicobacter pylori strikes again: gastric mucosa-associated lymphoid tissue (MALT) lymphoma

Infection with Helicobacter pylori is common. Over 50% of the world's population is estimated to be colonized with the bacteria. The association between Helicobacter pylori and gastric mucosa-associated lymphoid tissue (MALT) lymphoma is well documented. Anti-Helicobacter pylori treatment and the successful eradication of the bacteria can potentially cure patients who test positive for the bacteria and who are diagnosed with low-grade gastric MALT lymphoma. The purpose of this article is to review the evidence implicating Helicobacter pylori as a causal pathogen for the development of gastric MALT lymphoma and to determine that anti-Helicobacter pylori therapy is an effective first-line treatment. The clinical presentation, endoscopic findings, diagnosis, staging, treatment, and follow-up of patients with gastric MALT lymphoma who are treated with anti-Helicobacter pylori therapy are also discussed.

Recurrent gastric perforation as a late complication of radiotherapy for mucosa-associated lymphoid tissue lymphoma of the stomach

Radiation therapy can be used to treat Helicobacter pylori-negative or eradication-refractory extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) of the stomach. We report a case of gastric perforation which occurred more than 1 year after the completion of radiotherapy for H. pylori eradication-refractory gastric MALT lymphoma, and then recurred shortly afterwards. This was considered to be a late complication of radiation toxicity. Although gastric perforation due to radiotherapy has been reported very rarely in the past, even in advanced disease, this case shows that perforation can develop in patients with superficial disease and can relapse.

Lyme disease mimicking central nervous system lymphoma

A 33-year-old male presented with a complaint of intermittently blurred vision and right facial weakness. MRI of the brain and orbits revealed numerous cranial nerve abnormalities. There were no focal brain or spinal cord lesions. Cerebral spinal fluid flow cytometry revealed a monoclonal population of B-lymphoid cells. No other evidence of disease was found. Serum Lyme antibody was reported to be IgM positive. Therapy with ceftriaxone, was followed by improvement in his symptoms. Although flow cytometry is a useful tool in distinguishing malignancy from inflammatory disorders it does not always establish the diagnosis of malignancy by itself.

Therapy of gastric mucosa associated lymphoid tissue lymphoma

Gastric mucosa associated lymphoid tissue (MALT) lymphoma has recently been incorporated into the World Health Organization (WHO) lymphoma classification, termed as extranodal marginal zone B-cell lymphoma of MALT-type. In about 90% of cases this lymphoma is associated with H pylori infection which has been clearly shown to play a causative role in lymphomagenesis. Although much knowledge has been gained in defining the clinical features, natural history, pathology, and molecular genetics of the disease in the last decade, the optimal treatment approach for gastric MALT lymphomas, especially locally advanced cases, is still evolving. In this review we focus on data for the therapeutic, stage dependent management of gastric MALT lymphoma. Hence, the role of eradication therapy, surgery, chemotherapy and radiotherapy is critically analyzed. Based on these data, we suggest a therapeutic algorithm that might help to better stratify patients for optimal treatment success.

Multifocal extranodal mucosa-associated lymphoid tissue lymphoma affecting the larynx

OBJECTIVES

Extranodal marginal B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) accounts for about 7% to 8% of all B-cell lymphomas and 50% of all gastric lymphomas. Long-term localized growth is typical of MALT lymphoma. Multifocal manifestations are possible in advanced stages. MALT lymphoma of the larynx is a very rare disease; only 15 cases have been reported in the literature.

METHODS

We report a case of multifocal MALT lymphoma affecting the larynx associated with extraesophageal reflux, chronic laryngitis, and gastric Helicobacter pylori infection. The staging revealed a recurrent tumor of MALT lymphoma in the stomach and an involvement of the right conjunctiva.

RESULTS

Following recent reports on successful treatment of MALT lymphoma with antibiotics, initial empirical therapy with doxycycline calcium led to a subjective clinical symptom improvement but no objective response as assessed by laryngoscopy, magnetic resonance imaging of the larynx, and esophagogastroduodenal endoscopy. Because of the advanced stage and multiple extranodal manifestations of the MALT lymphoma, the patient received 3 cycles of chemoimmunotherapy according to the FCR protocol (fludarabine phosphate-cyclophosphamide-rituximab). No evidence of disease was observed after a 6-month follow-up.

CONCLUSIONS

In the rare diagnosis of MALT lymphoma of the larynx, comprehensive staging is indispensable to exclude multifocal involvement. In contrast to the treatment of primarily localized MALT lymphoma, multifocal disease warrants systemic therapy.

A case of mucosa-associated lymphoid tissue lymphoma forming multiple lymphomatous polyposis in the small intestine

A 50-year old woman suffering from diabetes had a CT scan that revealed a diffuse thickening of small intestinal wall and swollen paraaortic lymph nodes. An esophagogastroduodenoscopy (EGD) confirmed multiple polypoid lesions in the duodenum and small intestine, and conventional histological testing revealed non-specific inflammatory changes. Further examinations including the immunohistochemical profiles of the biopsied specimens led us to diagnose the lesion as a marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type, forming multiple lymphomatous polyposis sequentially spreading from duodenal bulb to terminal ileum. According to Lugano’s classification, its staging was clinically diagnosed as stage II. Two courses of a standard CHOP (cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and predonisolone) regimen with rituximab reduced the lesion and the patient had a almost complete response. A 5-year follow-up EGD and histological examinations detected no recurrence of the disease.

Gastric stump lymphoma after distal gastrectomy for benign peptic ulcer: Report of a case

We report a case of primary non-Hodgkin gastric stump lymphoma, found in a 78-year-old man 30 years after a distal gastrectomy for a benign peptic ulcer. The development of lymphoma in the gastric stump is rare. In fact, to our knowledge only 37 cases, including this one, have been documented. Although Helicobacter pylori is thought to be a predisposing factor, we found no histological evidence of this infection in our patient. Conversely, bile reflux and nitrite and N-nitrous compounds caused by abnormal bacterial growth in the gastric stump may play a role in inducing mucosa-associated lymphoid tissue lymphoma. The patient was treated by chemotherapy only, without surgery, which seems to be most appropriate for the early stages of this disease.

Hodgkin's and Non-Hodgkin's Lymphomas

The diagnosis and management of lymphoma have undergone significant changes in the past 20 years. For example, new immunophenotypic and molecular methods have replaced traditional histology-based classification schemes for lymphoma. Fluorine-18-deoxyglucose (FDG) positron emission tomography (PET) has evolved into a potent staging tool and prognostic indicator in many kinds of lymphoma. The role of radiation therapy, especially in patients who have early-stage Hodgkin's disease, has changed substantially. The introduction of anti-CD 20 antibody therapy (Rituximab) has improved the treatment of B-cell lymphoma. These changes are linked with higher expectations for imaging, such as detection of more subtle lymphoma manifestations, evaluation of residual changes, and better assessment of early response. This article reviews clinical and radiologic features of both Hodgkin's disease and non-Hodgkin's lymphoma. It also describes the radiologic staging of lymphoma and the emerging role of FDG-PET for assessing lymphoma.

Infectious Agents

There is substantial evidence that infectious agents play a causal role in a variety of human malignancies. These cancers include the liver, cervix, stomach, nasopharynx, bladder, and bile duct as well as Kaposi sarcoma (KS) and several lymphomas. This chapter summarizes the biological and epidemiologic features of each of the major oncogenic infections, beginning with the viruses, followed by H. pylori, and with a brief summary of the relevant parasites.

Successful treatment of Helicobacter pylori-negative gastric MALT lymphoma with rituximab

Helicobacter pylori infection is strongly associated with low-grade gastric lymphoma, commonly known as mucosa-associated lymphoid tissue (MALT) lymphoma. H. pylori eradication leads to complete remission in 80% of early stage MALT lymphomas. The treatment for early stage H. pylori-negative gastric MALT lymphoma is evolving. Rituximab, a chimeric anti-CD20 antibody, has shown response rates of approximately 50% with minimal toxicity in patients with B-cell non-Hodgkin lymphoma. We describe herein the clinical, endoscopic, and histologic features of a patient with H. pylori-negative gastric MALT lymphoma treated successfully with rituximab.

Clinical and endoscopic presentation of primary gastric lymphoma: a multicentre study

BACKGROUND

Although the stomach is the most frequent site of intestinal lymphomas, few data are available on both clinical endoscopic presentation of gastric lymphoma and possible differences between low-grade and high-grade lymphomas.

METHODS

Clinical, histological and endoscopic records of consecutive patients with primary low-grade or high-grade lymphoma diagnosed were retrieved. Symptoms were categorized as 'alarm' or 'not alarm'. The endoscopic findings were classified as 'normal' or 'abnormal'.

RESULTS

Overall, 144 patients with primary gastric lymphoma were detected, including 74 low-grade and 70 high-grade lymphoma. Alarm symptoms, particularly persistent vomiting and weight loss, were more frequently present in patients with high-grade lymphoma than in those with low-grade lymphoma (54% vs. 28%; P = 0.002). Low-grade lymphomas presented as 'normal' appearing mucosa (20% vs. 0%; P = 0.0004) or petechial haemorrhage in the fundus (9% vs. 0%; P = 0.02) more frequently than high-grade lymphomas, being also more often confined to the antrum (47% vs. 27%, P = 0.03) and associated with Helicobacter pylori infection (88% vs. 52%, P < 0.0001). On the contrary, high-grade lymphomas presented more commonly as ulcerative type (70% vs. 52%; P = 0.03), being also more frequently diagnosed in stage >I when compared with low-grade lymphomas (70% vs. 21%, P < 0.0001).

CONCLUSIONS

The overall prevalence of alarm symptoms is quite low and may be absent in more than 70% of patients with low-grade lymphoma.

A functional promotor polymorphism of TNF-alpha is associated with primary gastric B-Cell lymphoma

BACKGROUND AND AIMS

The host genetic background to develop primary gastric B-cell lymphoma in patients with chronic Helicobacter pylori infection is unknown. Tumor necrosis factor (TNF)-alpha plays a key role in H. pylori-associated inflammation and appears to be involved in the evolution of lymphoproliferative disorders. We investigated four functional promotor polymorphisms in the TNF-alpha gene for association with the development of primary gastric B-cell lymphoma.

PATIENTS AND METHODS

A total of 144 lymphoma patients, 595 H. pylori-infected controls and 534 healthy blood donors were genotyped for TNF-alpha-238, -308, -857, and -1031 by Taqman technology and case-control analysis was conducted.

RESULTS

There was no significant difference in allele and genotype frequencies in H. pylori-infected patients and healthy controls. TNF-857 T allele was found in 15.1% of patients with low-grade lymphoma and 9.1% of H. pylori-infected patients (Pearson's=5.7, p=0.017, OR=1.8, Wald 95% CI: 1.1< O.R.< 2.8). Carrier of the rare allele T had a 1.8-fold increased risk to develop low-grade lymphoma (Pearson's=5.4, p=0.021). Patients with high-grade lymphoma were significantly more frequent carriers of the TNF-857 T allele than healthy blood donors (30.9%vs 18.9%, Pearson's=4.5, p=0.033). Carriage of the T allele conferred a 1.9-fold increased risk (Wald 95% CI: 1.0<O.R.< 3.6). There were no associations found between any of the SNPs and disease progression.

CONCLUSION

In conclusion, our data provide further evidence for host genetic factors in the susceptibility of Caucasians to gastric B-cell lymphoma. Further studies are needed to elucidate the mechanistic role of TNF-alpha in tumorigenesis.

State-of-the-art therapeutics: marginal-zone lymphoma

Marginal-zone lymphomas comprise the mucosa-associated lymphoid tissue (MALT) type (extranodal marginal-zone lymphoma [EMZL]), the nodal marginal zone B-cell lymphoma (NMZL) and the splenic MZL (SMZL). EMZL is relatively common, whereas the remaining two entities are relatively rare disorders. EMZL, especially in its gastric localization, is the most studied MZL, and there are many data both on the underlying genetic lesions and on the role of infectious agents. These data have determined unique approach among all other lymphoma subtypes: the possibility of treating a subset of patients with antibiotics alone as first line of treatment. Indeed, there is compelling evidence that histologic regressions can be achieved in most gastric MALT lymphomas by eradicating Helicobacter pylori infection. However, molecular follow-up studies showed the persistence of the malignant clone in half of the cases in histologic remission after antibiotic treatment and transient, either histologic or molecular, relapses have been reported, too. Hence, a careful long-term follow-up is mandatory after antibiotic treatment. Radiotherapy, chemotherapy, anti-CD20 monoclonal antibodies are effective alternative therapies. The precise role of surgical resection should be redefined in view of the encouraging results of conservative approaches. Differently from EMZL, both SMLZ and NMZL often present with disseminated disease at diagnosis. The therapeutic approach comprises splenectomy, for SMZL, and chemotherapy, but with no consensus about the best treatment. This review addresses the current knowledge on the clinical features and therapeutic approaches for the individual MZLs.

Primary gastrointestinal lymphomas: A radiological-pathological review. Part 1: Stomach, oesophagus and colon

Primary gastrointestinal lymphomas are most common in the stomach, followed by small intestine and then colon. The most frequently used pathology classification of lymphomas is the Revised European and American Lymphoma /World Health Organization classification. The correlation of radiological morphology with histology is relatively poor, although characteristic subtypes will be discussed. In the stomach, the majority of primary lymphomas are of B-cell origin of mucosa-associated lymphoid tissue (MALT) type. Low-grade MALT lymphomas are associated with Helicobacter pylori infection and often respond to eradication of this organism. Radiological features include thickened folds, nodularity, depressed lesions, ulcers, prominent areae gastricae. High-grade (large B-cell) tumour patterns include infiltrative, polypoid, nodular, ulcerated or a combination. Endoscopy, endoscopic ultrasound and CT are important in diagnosis and staging, although appearances on barium studies should be recognized. Primary colonic lymphomas are rare. Most are of B-cell origin. Focal and diffuse forms are seen, the former producing polypoid or nodular or cavitating masses and the latter producing ulcerative or nodular (polyposis) patterns on imaging. Even when circumferential, lymphoma rarely causes obstruction. Small bowel lymphomas will be discussed in the forthcoming part 2 of this review.

Pathogen evolution in vivo: genome dynamics of two isolates obtained 9 years apart from a duodenal ulcer patient infected with a single Helicobacter pylori strain

The survival and microevolution of Helicobacter pylori strains in the niches of the stomach after eradication therapy have largely been unexplored. We analyzed genomic signatures for two successive isolates obtained 9 years apart from a duodenal ulcer patient who underwent eradication therapy for H. pylori. These isolates were genotyped based on 50 different parameters involving three different fingerprinting approaches and several evolutionarily significant and virulence-associated landmarks in the genome, including nine informative gene loci, the cag pathogenicity island and its right junction, members of the plasticity region cluster, and vacA and iceA alleles. Our observations reveal that the two isolates were derived from the same strain that colonized the patient for almost a decade and were almost identical. Microevolution, however, was observed in the cagA gene and its right junction, the vacA m1 allele, and a member of the plasticity region cluster (JHP926). These results suggest that H. pylori has a great ability to survive and reemerge as a microevolved strain posteradication, thereby hinting at the requirement for follow-up of patients after therapy.

Molecular analysis of B-cell clonality in Helicobacter pylori gastritis

The aim of our study was to identify PCR-detectable clonal B-cell population in Helicobacter pylori gastritis and assess their relation to the Wotherspoon-Isaacson (W-I) grade for gastric lymphoid infiltrates. Amplified DNA was obtained from thirty four H. pylori positive gastritis dyspeptic patients and thirty four H. pylori negative matched controls. Clonal bands were observed in 6 (2/17 W-I Grade 1, 2/13 W-I Grade 2, and 2/4 W-I Grade 3 lesions) and polyclonal smears in 24 cases (15 W-I Grade 1, 7 W-I Grade 2, and 2 W-I Grade 3). Four additional W-I Grade 2 samples with clonal bands were associated with background polyclonal smear and were not reproducible. Clonal bands were not recorded in controls. B-cell clonality was not related to W-I grades. We conclude that certain H. pylori positive gastritis patients show PCR-detectable monoclonality, which is independent of the W-I grade of gastritis and cannot be taken as evidence of an existing neoplastic lesion.

16S rRNA mutations that confer tetracycline resistance in Helicobacter pylori decrease drug binding in Escherichia coli ribosomes

Tetracycline resistance in clinical isolates of Helicobacter pylori has been associated with nucleotide substitutions at positions 965 to 967 in the 16S rRNA. We constructed mutants which had different sequences at 965 to 967 in the 16S rRNA gene present on a multicopy plasmid in Escherichia coli strain TA527, in which all seven rrn genes were deleted. The MICs for tetracycline of all mutants having single, double, or triple substitutions at the 965 to 967 region that were previously found in highly resistant H. pylori isolates were higher than that of the mutant exhibiting the wild-type sequence of tetracycline-susceptible H. pylori. The MIC of the mutant with the 965TTC967 triple substitution was 32 times higher than that of the E. coli mutant with the 965AGA967 substitution present in wild-type H. pylori. The ribosomes extracted from the tetracycline-resistant E. coli 965TTC967 variant bound less tetracycline than E. coli with the wild-type H. pylori sequence at this region. The concentration of tetracycline bound to the ribosome was 40% that of the wild type. The results of this study suggest that tetracycline binding to the primary binding site (Tet-1) of the ribosome at positions 965 to 967 is influenced by its sequence patterns, which form the primary binding site for tetracycline.

The emerging role of endoscopic ultrasonography in cancer staging

The management of solid organ cancers relies on accurate staging. Once distal metastasis has been excluded by conventional radiographic methods, local staging of the tumor and its nodal involvement is essential to determine the most optimal therapeutic approach. Many radiographic imaging modalities are unable to determine subtle tumor involvement. However, the emergence of endoscopic ultrasonography (EUS) has given promise to improved staging with its unique ability to examine tumors from within the gastrointestinal lumen with extremely close proximity. An additional advantage is the ability to perform fine-needle aspiration (FNA) biopsy to confirm or exclude tumor involvement. Many studies have shown superior accuracy in staging with EUS and EUS-FNA for tumors of the esophagus, stomach, pancreas, rectum, and mediastinum, including lung cancer. This review illustrates the principles of EUS and its role in staging of a variety of cancers and particularly its role alongside other imaging modalities.

Helicobacter pylori and gastroduodenal pathology: new threats of the old friend

The human gastric pathogen Helicobacter pylori causes chronic gastritis, peptic ulcer disease, gastric carcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma. It infects over 50% of the worlds' population, however, only a small subset of infected people experience H. pylori-associated illnesses. Associations with disease-specific factors remain enigmatic years after the genome sequences were deciphered. Infection with strains of Helicobacter pylori that carry the cytotoxin-associated antigen A (cagA) gene is associated with gastric carcinoma. Recent studies revealed mechanisms through which the cagA protein triggers oncopathogenic activities. Other candidate genes such as some members of the so-called plasticity region cluster are also implicated to be associated with carcinoma of stomach. Study of the evolution of polymorphisms and sequence variation in H. pylori populations on a global basis has provided a window into the history of human population migration and co-evolution of this pathogen with its host. Possible symbiotic relationships were debated since the discovery of this pathogen. The debate has been further intensified as some studies have posed the possibility that H. pylori infection may be beneficial in some humans. This assumption is based on increased incidence of gastro-oesophageal reflux disease (GERD), Barrett's oesophagus and adenocarcinoma of the oesophagus following H. pylori eradication in some countries. The contribution of comparative genomics to our understanding of the genome organisation and diversity of H. pylori and its pathophysiological importance to human healthcare is exemplified in this review.

Detection of Helicobacter pylori in the stools of newborn infants

To investigate the transmission route of Helicobacter pylori, stool specimens of 50 infants 3 days old were studied by a stool antigen immunoassay and polymerase chain reaction (PCR). By PCR, H. pylori DNA was detected in 15 neonates (30%). The stool antigen test was positive in only 1 neonate with a positive PCR. The detection rate of H. pylori DNA in neonates was significantly higher for those with mothers having urines positive for anti-H. pylori IgG antibody (60%) than for those mothers with negative urines (17%) (P < 0.01). A follow-up study was done 24 months later on 8 of the 15 infants with positive PCR results, including the infant with a positive stool antigen test. All infants were negative by both PCR and stool antigen test.

A case of primary mucosa-associated lymphoid tissue lymphoma of the vagina

We report the first case of primary mucosa-associated lymphoid tissue (MALT) lymphoma of the vagina, the diagnosis of which is supported by genetic and immunophenotypic studies. A 65-year-old, para 2 woman presented to our hospital in July 1997 with a history of prolonged vaginal discharge. Although cytologic examination suggested possible malignancy, a biopsy of the vaginal wall was diagnosed as chronic inflammation. In June 2000, she underwent gynecologic examination because of anuria. Excisional biopsy revealed subepithelial infiltration of atypical lymphoid cells that stained for CD20, CD79a, and BCL-2; stained weakly for IgM; and did not stain for CD3, CD5, CD7, CD10, CD56, CD23, and IgD, suggesting marginal zone B-cell lineage. Monoclonality was detected by Southern blot analysis, and this patient was finally diagnosed as having primary MALT lymphoma of the vagina. She received 3 cycles of chemotherapy (THP-COP) and concurrent radiation to the whole pelvis. The patient is alive and well 40 months after treatment. Because the vagina is one of the mucosa-associated tissues, MALT lymphoma, though rare, must be included in the differential diagnosis of the vaginal neoplasms.

Marginal Zone B-cell Lymphoma (MALT Lymphoma)

The preferred terminology for mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach (variously referred to as MALT lymphoma, MALToma, low-grade MALToma, or pseudolymphoma) is marginal zone B-cell lymphoma (MZBL). MZBL, the hallmark of which is the lymphoepithelial lesion, develops as a consequence of Helicobacter pylori infection in susceptible individuals. In general, MZBL is slow growing, can remain localized for years, and has an excellent prognosis. Staging involves endoscopy with biopsy, computed tomography scanning, and endoscopic ultrasound. In patients with limited disease, eradication of H. pylori leads to remission. In patients who fail eradication therapy or have more extensive disease, surgery, chemotherapy, and radiation alone and in various combinations have been used successfully.

Persistent infection with Helicobacter pylori and the development of gastric cancer

Gastric malignancies have been closely linked to infection of the gastric mucosa with Helicobacter pylori, but the individual factors involved in the multistage process of tumor development are still poorly understood. H. pylori evades the host defense system and causes persistent infection and chronic inflammation. Immune activation leads to DNA damage by the release of oxygen and nitrogen radicals. Ongoing tissue repair mechanisms and the secretion of cytokines and growth factors, as well as bacterial effector molecules, cause disturbances in the balance between epithelial cell proliferation and apoptosis, promote the accumulation of potential oncogenic mutations, and support neovascularization and tumor growth. In addition, H. pylori might hamper the development of an efficient antitumor immunity and provoke immune-mediated pathology. This review summarizes the recent progress in the understanding of the intimate bacteria-host relationship and the mechanisms by which H. pylori may promote the process of tumor development.