Cell kinetic balance in gastric mucosa with intestinal metaplasia after Helicobacter pylori eradication: 2-year follow-up study

Evaluation of apoptosis along with BCL-2 and Ki-67 expression in patients with intestinal metaplasia

The primary aim is to compare individuals with intestinal metaplasia (IM), chronic active gastritis (CAG), and normal gastric mucosa (NGM) in terms of apoptosis, proliferation, and Bcl-2 expression. The secondary aim is to determine whether these parameters are different between patients with and without gastric cancer in first-degree relatives. We enrolled 106 patients whose histopathological results were consistent with IM (n: 42), CAG (n: 51), or NGM (n: 13). Antral biopsies were immunohistochemically stained for Bcl-2 and Ki-67 expression. Apoptosis was detected using TUNEL assay. While no significant difference was determined between three groups with regard to apoptosis and Bcl-2 expression (p>0.05), Ki-67 expression was significantly higher in the IM group when compared with the CAG and NGM groups (29.90±22.87 vs. 18.18±16.22 vs. 18.54±20, respectively; p=0.012). Helicobacter pylori was determined to increase apoptosis (49.3% vs. 25.7%, p<0.05), nevertheless, it had no significant effect on proliferation and Bcl-2 expression. Bcl-2 and Ki-67 expression and apoptosis were not different among patients with and without a history of gastric cancer in first degree relatives. Although intestinal metaplasia cases demonstrate an increase in proliferation, no elevation is observed in apoptosis. This can be an important factor in the progression to gastric cancer.

BCL2L10 protein regulates apoptosis/proliferation through differential pathways in gastric cancer cells

The reason for and consequences of BCL2L10 down-regulation in gastric carcinoma are poorly understood. Our aim was to investigate the function of the protein BCL2L10 in gastric carcinoma. We investigated BCL2L10 expression using quantitative real-time PCR and immunoblotting. The methylation status of the BCL2L10 gene promoter was examined by bisulphite sequencing in fresh gastric normal and carcinoma tissues. We studied apoptosis and proliferation regulation in gastric cancer cell lines using flow cytometry, fluorescence staining, murine xenografting and immunoblotting. Pathway inhibitors were applied to confirm the major pathways involved in apoptosis or proliferation regulation. We observed significant correlations between lower BCL2L10 expression and CpG island hypermethylation of the BCL2L10 gene promoter in gastric carcinoma, apoptosis induced by over-expressed BCL2L10 through mitochondrial pathways, and proliferation accelerated by BCL2L10 siRNA via the PI3K-Akt signalling pathway in gastric cancer cell lines. The pro-apoptotic effect of BCL2L10 and growth promotion by BCL2L10 siRNA in gastric cancer cells suggest that it may be a tumour suppressor.

Alterations in mucin expression in ovarian mucinous tumors: immunohistochemical analysis of MUC2, MUC5AC, MUC6, and CD10 expression

The aim of this study was to evaluate the immunohistochemical expression of MUC2, MUC5AC, MUC6, and CD10 in ovarian mucinous adenoma (MA), mucinous borderline tumor (MB), and mucinous adenocarcinoma (MC), and to analyze the relationship between prognosis and these expressions. The expression of MUC2, MUC5AC, MUC6, and CD10 was evaluated by immunohistochemical analysis in 29 cases of MA, 29 cases of MB, and 26 cases of MC and scored based on the percentage of positive cells. Moreover, the ovarian mucinous tumors were classified into 4 phenotypes based on the staining patterns: intestinal, gastrointestinal, gastric, and unclassified patterns. The gastrointestinal pattern and the expression of MUC2 and CD10 increased from MA to MC. Conversely, the gastric pattern and MUC5AC expression decreased from MA to MC. Low MUC2 expression in MC was correlated with a better long-term survival rate. MUC2 expression in MC may be a useful predictor of the clinical outcome. The expression patterns of MUC2, MUC5AC, MUC6, and CD10 indicated that intestinal metaplasia may arise from the gastric-like epithelium in MA and that a close association exists between carcinogenesis and intestinal metaplasia in major ovarian mucinous tumors.

Helicobacter pylori-induced changes in the gastric mucosa are associated with mitogen-activated protein kinase (MAPK) activation

BACKGROUND

Gastric cancers are usually associated with and preceded by Helicobacter pylori (HP) infection, gastric atrophy, intestinal metaplasia, and dysplasia. HP infection alters cell kinetics of the gastric mucosa. Both proliferation and apoptosis are increased. Proinflammatory cytokines are responsible for some of these alterations. The mitogen-activated protein kinase (MAPK) signaling pathway has been implicated as a causative factor in these alterations based on in vitro studies. In this study, we investigated the effects of HP infection on gastric mucosal proliferation, apoptotic mechanisms, and the activation status of the MAPK signaling pathway at various stages of gastric carcinogenesis, especially intestinal metaplasia and dysplasia caused by HP infection.

DESIGN

Stomach biopsies representing normal (n=20), HP+ (n=25), HP+ with intestinal metaplasia (n=25), HP+ with dysplasia (n=15) and gastric adenocarcinoma (n=30; 20 HP+ and 10 HP-) cases were selected. Cell proliferation was assessed by proliferating cell nuclear antigen immunostaining. Apoptosis and survival-related markers; cleaved caspase-3, and phospho-MAPK extracellular signal-regulated kinase (ERK) were detected by immunohistochemical methods.

RESULTS

Proliferation index (proliferating cell nuclear antigen) and cleaved caspase-3 expression were higher in the HP+, HP+ with intestinal metaplasia, and HP+ with dysplasia groups than in normal controls (P<0.05). Cleaved caspase-3 activity was also high in the adenocarcinomas. Phospho-MAPK(ERK) expression was increased in the HP+, HP+ with intestinal metaplasia, HP+ with dysplasia and adenocarcinomas compared with the normal control group. Whereas HP- gastric carcinomas had a lower expression of phospho-MAPK.

CONCLUSIONS

HP infection increases the proliferative rate of gastric foveolar cells in conjunction with an increased apoptotic rate and activation of MAPK(ERK). MAPK activation seems to be a significant and persistent event in the HP-induced neoplastic transformation.