A clinicopathologic study of gastric mucosa-associated lymphoid tissue lymphoma

Effectiveness of Helicobacter pylori eradication in the treatment of early-stage gastric mucosa-associated lymphoid tissue lymphoma: An up-to-date meta-analysis

BACKGROUND

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma (GML) is usually a low-grade B-cell neoplasia strongly associated with Helicobacter pylori (H. pylori)-induced chronic gastritis. Clinical practice guidelines currently recommend H. pylori eradication as the preferred initial treatment for early-stage GML. To determine the practical effect of bacterial eradication as the sole initial therapy for early-stage GML, an updated analysis and review of available evidence is imperative.

AIM

To perform a meta-analysis to assess the rate of complete remission (CR) of H. pylori-positive early-stage GML following bacterial eradication.

METHODS

We performed independent, computer-assisted literature searches using the PubMed/MEDLINE, Embase, and Cochrane Central databases through September 2022. Prospective and retrospective observational studies evaluating the CR of early-stage GML following bacterial eradication in H. pylori-positive patients. The risk of bias was assessed using Joanna Briggs Institute (JBI) Critical Appraisal Tools. The pooled estimate of the complete histopathological remission rate and respective confidence intervals (95%CI) were calculated following the random-effects model. Heterogeneity and inconsistency were assessed using Cochran’s Q test and I² statistic, and heterogeneity was defined as P < 0.01 and I² > 50%, respectively. Subgroup and meta-regression analyses were conducted to explore potential sources of heterogeneity.

RESULTS

The titles and abstracts of 1576 studies were screened; 96 articles were retrieved and selected for full-text reading. Finally, 61 studies were included in the proportional meta-analysis (P-MA). Forty-six were prospective and fifteen were retrospective uncontrolled, single-arm, observational studies. The overall risk of bias was low to moderate in all but a single report, with an average critical appraisal score across all studies of 79.02%. A total of 2936 H. pylori-positive early-stage GML patients, in whom H. pylori was successfully eradicated, were included in the analysis. The pooled CR of H. pylori-positive early-stage GML after bacterial eradication was 75.18% (95%CI: 70.45%-79.91%). P-MA indicated the substantial heterogeneity in CR reported across studies (I² = 92%; P < 0.01). Meta-regression analysis identified statistically significant effect modifiers, including the proportion of patients with t(11;18)(q21;q21)-positive GML and the risk of bias in each study.

CONCLUSION

Comprehensive synthesis of available evidence suggests that H. pylori eradication is effective as the sole initial therapy for early-stage GML. Although the substantial heterogeneity observed across studies limits the interpretation of the pooled overall CR, the present study is a relevant to informing clinical practice.

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.

Expression of COX-2, iNOS, p53 and Ki-67 in gastric mucosa-associated lymphoid tissue lymphoma

AIM: To assess the expression of cyclooxygenase-2 (COX-2), nitric oxide synthase (iNOS), p53 and Ki-67 in gastric mucosa-associated lymphoid tissue (MALT) lymphoma and clarify the relationship between COX-2 expression and iNOS or p53 expression in these patients.

METHODS: The expressions of COX-2, iNOS, p53 and Ki-67 were detected in 32 gastric MALT lymphoma specimens and 10 adjacent mucosal specimens by immunohistochemical Envision method.

RESULTS: COX-2 and iNOS expressions were significantly higher in gastric MALT lymphoma tissues than those in adjacent normal tissues. The expression of COX-2 was observed in 22 of 32 cases of MALT lymphoma tissues (68.8%). A positive cytoplasmic immunoreactivity for iNOS was detected in 17 of 31 cases (53.1%). COX-2 expression in gastric MALT lymphoma tissues was positively correlated with iNOS expression (r = 0.448, P = 0.010) and cell proliferative activity analyzed by Ki-67 labeling index (r = 0.410, P = 0.020). The expression of COX-2 protein did not correlate with age, sex, stage of disease, lymph node metastasis or differentiation. The accumulation of p53 nuclear phosphoprotein was detected in 19 (59.4%) of tumors. p53 protein was expressed in 11 of 23 assessed LG tumors and in 8 of 9 assessed HG tumors. The difference of p53 positivity was found statistically significant between LG and HG cases (P = 0.0302). The p53 accumulation correlated with advanced clinical stage (stage III + IV vs stage I + II, P = 0.017). There was a significant positive correlation between COX-2 expression and p53 accumulation status (r = 0.403, P = 0.022). The mean PI of Ki-67 in each grade group were 36.0% ± 7.73% in HG and 27.4% ± 9.21% in LG. High-proliferation rate correlated with HG tumors (r = 0.419, P = 0.017). The correlation coefficient showed a significant positive correlation between PI and COX-2 expression in MALT lymphoma patients (r = 0.410, P = 0.020).

CONCLUSION: COX-2 expresses in the majority of gastric MALT lymphoma tissues and correlates with cellular proliferation and iNOS expression. COX-2 overexpression is closely associated with p53 accumulation status. iNOS and COX-2 may play a synergistic role in the pathogenesis of gastric MALT lymphoma.

Relationship between expression of Bcl-2 and p53 protein and CagA+Helicobacter pylori in gastric cancer

AIM

The relationship between cytotoxin-associated protein (CagA)+Helicobacter pylori (H.pylori) infection and gastric cancer in China was reported inconsistently. Using enzyme-linked immunosorbent assay (ELISA) to detect serum anti-CagA antibody and ABC immunohistochemical staining to detect the expression of Bcl-2 and p53 proteins, this study is to explore the relationship between CagA H.pylori infection and expressions of p53 and Bcl-2 proteins in gastric cancer and chronic gastric diseases.

METHODS

Seventy-nine patients (50 with gastric cancer, 17 with chronic atrophic gastritis, 5 with gastric ulcer and 7 with chronic superficial gastritis) were diagnosed by endoscopy and biopsied under endoscopy for detection of H.pylori infection, and confirmed by pathological examination. Expression of Bcl-2 and p53 proteins was detected by immunohistoche-mistry. Rapid urease test and serum H.pylori antibodies with ELISA or Warthin-Starry silver stains were used for H.pylori diagnosis. H.pylori was defined as positive when 2 or 3 of these tests were positive. ELISA was used for the detection of serum anti-CagA antibody.

RESULTS

Anti-CagA antibody was present in 43/50(86%) gastric cancer and in 13/29 (41%) chronic gastric disease, CagA+H.pylori rate in gastric cancer was higher than those in chronic gastric diseases (P<0.01). The positive rate of Bcl-2 expression in gastric cancer was higher than that in chronic gastric diseases (62% vs 41%, P>0.05). In CagA+ gastric cancer it was higher than that in CagA- one (65% vs 43%, P>0.05), and in CagA+ chronic gastric diseases it was higher than that in CagA- one (77% vs 12%, P<0.01). The positive rate of mutant p53 expression in gastric cancer was higher than that in chronic gastric diseases (54% vs 28%, P<0.05), in CagA+ gastric cancer it was significantly higher than that in CagA- one (60% vs 14%, P<0.05), and in CagA⁺ chronic gastric diseases it was significantly higher than that in CagA- ones (46% vs 12%, P<0.05).

CONCLUSION

Expression of anti-CagA antibody is present in a significantly higher percentage of gastric cancer subjects than that in chronic gastric diseases. It is suggested that CagA⁺H.pylori infection may increase the risk of gastric cancer. The CagA factor may be involved in the development of gastric cancer through influencing the expression of Bcl-2 gene and mutant p53 gene.