Analysis of cell damage and proliferation in Helicobacter pylori-infected human gastric mucosa from patients with gastric adenocarcinoma.

Helicobacter pylori (HP) infection, a cause of multifocal atrophic gastritis, is considered an important factor related to the evolution of the human gastric mucosa from normal to intestinal-type adenocarcinoma. We examined cell proliferation and both double and single strand DNA damage in situ in 35 patients undergoing gastrectomy for adenocarcinoma with HP-infected gastric mucosa by immunolocalization of Ki-67, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling, and in situ nick translation. We also studied the distribution of intraepithelial neutrophils by elastase immunolocalization. HP infection was confirmed in all cases by serum anti-HP antibodies, ureas testing, and histopathological examination. HP-infected gastric mucosa was classified according to the degree of inflammation and intestinal metaplasia. Ki-67, terminal deoxynucleotidyl transferase-mediated labeling, in situ nick translation, and intraepithelial neutrophil indices all increased with the progression of gastritis and were highest in glands with incomplete intestinal metaplasia. All indices were lowest in gastric glands with complete intestinal metaplasia. Significant positive correlations were observed among these markers. Increased proliferative activity in HP-associated chronic gastritis in response to cell damage or injury was clearly demonstrated, suggesting that both HP-associated toxins and intraepithelial neutrophils are important in HP-related gastric epithelial injury. Increased cell turnover associated with incomplete intestinal metaplasia may result in DNA instability and subsequent development of intestinal-type gastric adenocarcinoma in HP-infected mucosa.     

Analysis of cell damage in Helicobacter pylori-associated gastritis

Helicobacter pylori infection is currently considered to be a major cause of acute and chronic gastritis, and of gastric and duodenal ulcers. Superoxide dismutase (SOD) is well known for scavenging superoxide radicals such as reactive oxygen species (ROS), subsequently protecting cells from oxidative injury, and for maintaining tissue homeostasis. In this study, we therefore evaluated the level of SOD activity and protein expression, as well as various factors associated with oxidative injury, in H. pylori-positive (n = 46) and -negative (n = 28) gastric mucosa obtained from endoscopy, in order to elucidate the possible biological significance of SOD in these mucosa. Overall SOD activity was significantly higher in H. pylori-positive mucosa (15.5 +/- 7.0 U/mg protein) than in negative mucosa (9.2 +/- 10.6 U/mg protein), and decreased markedly following H. pylori eradication (8.2 +/- 4.2 U/mg protein). Enzyme-linked immunosorbent assay (ELISA) analysis of SOD revealed that the manganese SOD (Mn-SOD) level in H. pylori-positive mucosa (1166.7 +/- 435.2 ng/mg protein) was significantly higher than in control tissues (446.3 +/- 435.3 ng/mg protein) and in mucosa obtained following eradication therapy (431.9 +/- 189.9 ng/mg protein). The level of Mn-SOD protein showed a significant correlation with degree of inflammation in the gastric mucosa. Moreover, Mn-SOD immunolocalization patterns were well correlated with the activity and protein levels evaluated by ELISA. Factors presumably associated with oxidative injury in human gastric mucosa, including terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling, Ki-67, 8-hydroxydeoxyguanosine and single-stranded DNA, were all significantly higher in H. pylori-positive gastric mucosa than in control tissue and in tissue following eradication. These results all suggest that Mn-SOD, but not cytoplasmic copper-zinc SOD, plays an important role as an anti-oxidant against ROS generated in H. pylori-infected gastric mucosa and, subsequently, in the maintenance of cell turnover in gastric mucosa.     

Apoptosis and cell proliferation in biliary atresia

Biliary atresia (BA), which is thought to result from progressive destruction of the bile ducts by a necroinflammatory process, is the most common cause of obstructive jaundice in infancy. Abnormalities in the cell turnover of remodelling ductal plates are considered one of the important aetiological factors in this disorder, but little work has been done on this topic. Programmed cell death or apoptosis was therefore examined by TdT-mediated dUTP biotin nick end labelling (TUNEL) and cell proliferation by Ki67 immunostaining in 34 cases of BA. The results were compared with normal control liver (five cases) and congenital dilatation of the bile ducts (CDB, five cases) in order to study the cell turnover or tissue dynamics of BA. The TUNEL labelling index (LI) in bile ducts (48.9 +/- 13.2 per cent) was significantly higher than that of the control normal liver (3.6 +/- 2.8 per cent) and of CDB (2.5 +/- 5.1 per cent). The Ki67 LI in the bile ducts of BA (15.0 +/- 5.57 per cent) was also significantly higher than that of CDB (8.6 +/- 5.4 per cent). No significant differences of the TUNEL and Ki67 LIs in hepatocytes were, however, observed between BA, CDB, and normal liver. The TUNEL LI was significantly higher than the Ki67 LI in the bile ducts of BA. BA is therefore associated with increased and disorganized cell turnover of the bile ducts, which is related to malformation of the ductal plate or abnormal bile duct development.     

Localization of antigen-presenting cells in Helicobacter pylori-infected gastric mucosa

Helicobacter pylori (HP) infection is known to induce the specific immune response in the gastric mucosa. The immune response is triggered by presentation of antigen peptides on the major histocompatibility assembly of the antigen-presenting cells (APC) with the assistance of costimulatory molecules such as B7-1 (CD80) and B7-2 (CD86). Their counter-receptors or ligands on T cells are CD28 or cytotoxic lymphocyte-associated molecule-4. The aim of the present study was to clarify the localization of APC and their relation with T cells in HP-infected human gastric mucosa. Our findings suggest that the macrophages in the lamina propria may mainly act as APC in the HP-infected gastric mucosa, and the triggered immune response might be involved in the mucosal immune response in the inflamed gastric mucosa to invasive antigens related to HP organisms.     

Alterations in the proliferating compartment of gastric mucosa during Helicobacter pylori infection: the putative role of epithelial cells expressing p27(kip1).

The proliferating zone contains stem cells that give rise to all epithelial cells of the gastric mucosa. In the present study, we investigated the turnover of gastric epithelial cells in the proliferating zone of Helicobacter pylori-infected mucosa, with or without intestinal metaplasia, before and after eradication of the microorganism. In addition, we studied the topographical distribution of the cyclin dependent kinase inhibitor p27(Kip1), which plays a critical role in cell cycle progression and differentiation programs. Twenty-eight patients (22 male), aged 32-78 years and with dyspeptic symptoms, were endoscoped, and gastric biopsies were obtained from antrum and corpus for histopathological examination and the Campylobacter-like organisms test; eradication therapy was given to infected patients, and all patients were re-endoscoped after 105 +/- 33 days (mean +/- SD). The kinetics of gastric epithelial cells and p27(Kip1) status was assessed by means of immunohistochemistry and TUNEL (Tdt-mediated dUTP-biotin nick end labeling) assay. Twenty-one (21) of 28 patients were H. pylori positive, and 7 were found H. pylori negative and served as controls. In antrum, intestinal metaplasia was detected in 7/21 (33.3%). In H. pylori gastritis, Ki67 expression was found increased in the proliferating zone, compared with normal (P =.03); analogous results were obtained with the other proliferation markers, namely retinoblastoma protein and topoisomerase IIalpha. An inverse relationship between proliferation index and atrophy was disclosed (P =.02). A reduction in the proliferation index was observed after eradication, albeit not significant. Apoptotic epithelial cells were found significantly increased (P <.01) in H. pylori gastritis, and a significant reduction was observed after eradication (P <.01). In addition, apoptotic index was found to correlate with H. pylori density. The topographical study of p27(Kip1) revealed a p27(kip1)-positive epithelial cell population that resided deep in the proliferating zone; these cells were considered to be stem cells and were found significantly increased in areas with intestinal metaplasia (P <.05); in H. pylori gastritis, there was also an increase that did not reach statistical significance. H. pylori infection induces apoptosis and increases proliferation in the proliferating zone. The increased cellular turnover, together with the increased number of putative p27(Kip1)-positive stem cells in the context of intestinal metaplasia, provides further evidence for the role of H. pylori infection in gastric carcinogenesis.     

IN SITU ANALYSIS OF TISSUE DYNAMICS AND p53 EXPRESSION IN HUMAN GASTRIC MUCOSA

In situ tissue dynamics were studied in 12 cases of human gastric mucosa, including normal gastric body mucosa and gastric glands with intestinal metaplasia, obtained from gastrectomy specimens of adenocarcinoma. Cell proliferation was determined by Ki67 immunoreactivity. DNA fragmentation was studied in situ by TdT-mediated dUTP-biotin nick end labelling (TUNEL). In addition, p53 expression was examined by both immunohistochemistry and mRNA in situ hybridization. In the oxyntic gastric glands, Ki67 immunoreactivity was observed exclusively in the proliferative zone and TUNEL-positive cells were present predominantly in the surface foveolar epithelium. In the gastric glands with complete intestinal metaplasia, Ki67-positive cells were present in the lower portion of the glands and TUNEL-positive cells in the superficial epithelium. In the gastric glands with incomplete intestinal metaplasia, TUNEL-positive cells were detected in the lower gastric glands adjacent to cells immunoreactive for Ki67; the proportion of these gastric glands with TUNEL-positive cells (40 out of 108 glands) was significantly higher than for oxyntic glands (94 out of 620 glands) or for glands with complete metaplasia (31 out of 254 glands). Relatively strong p53 immunoreactivity and mRNA hybridization were also observed in the proliferative and apoptotic areas of gastric glands with incomplete intestinal metaplasia. These results indicate that incomplete intestinal metaplasia is associated with increased cell turnover and p53 overexpression, possibly in response to various noxious or DNA-damaging stimuli.     

T cell proliferation and apoptosis in HIV-1-infected lymphoid tissue: impact of highly active antiretroviral therapy.

T cell turnover was studied in situ in tonsillar lymphoid tissue (LT) from HIV-1-infected individuals during 48 weeks of highly active antiretroviral therapy (HAART) and compared to that of HIV-1-negative controls. Prior to therapy, CD4 cell proliferation (%CD4+ Ki67+) and apoptosis (%CD4+ TUNEL+) were increased in HIV-1-infected LT and both parameters correlated with tonsillar viral load. CD8 cell proliferation (%CD8+ Ki67+) was increased 4- to 10-fold, mainly in the germinal centers. Apoptotic CD8+ T cell levels (%CD8+ TUNEL+) were raised preferentially in the tonsillar T cell zone. The frequency of CD8+ Ki67+ and CD8+ TUNEL+ T cells correlated with tonsillar viral load and with the fraction of CD8(+) T cells expressing activation markers. During HAART, CD4 cell turnover normalized while CD8 cell turnover was dramatically reduced. However, low level viral replication concomitant with slightly elevated levels of CD8 cell turnover indicated a persistent cellular immune response in LT. In conclusion, enhanced T cell turnover may reflect effector cells related to HIV-1 infection.     

Homeostatic mass control in gastric non-neoplastic epithelia under infection of Helicobacter pylori: an immunohistochemical analysis of cell growth, stem cells and programmed cell death

We evaluated homeostatic mass control in non-neoplastic gastric epithelia under Helicobacter pylori (HP) infection in the macroscopically normal-appearing mucosa resected from the stomach with gastric cancer, immunohistochemically analyzing the proliferation, kinetics of stem cells and programmed cell death occurring in them. Ki67 antigen-positive proliferating cells were found dominantly in the elongated neck portion, sparsely in the fundic areas and sporadically in the stroma with chronic infiltrates. CD117 could monitor the kinetics of gastric stem cells and showed its expression in two stages of gastric epithelial differentiation, namely, in transient cells from the gastric epithelial stem cells to the foveolar and glandular cells in the neck portion and in what are apparently progenitor cells from the gastric stem cells in the stroma among the infiltrates. Most of the nuclei were positive for ssDNA in the almost normal mucosa, suggesting DNA damage. Cleaved caspase-3-positive foveolar cells were noted under the surface, suggesting the suppression of apoptosis in the surface foveolar cells. Besides such apoptosis of the foveolar cells, in the severely inflamed mucosa apoptotic cells were found in the neck portion where most of the cells were Ki67 antigen-positive proliferating cells. Beclin-1 was recognized in the cytoplasm and in a few nuclei of the fundic glandular cells, suggesting their autophagic cell death and mutated beclin-1 in the nuclei. Taken together, the direct and indirect effects of HP infection on the gastric epithelial proliferation, differentiation and programmed cell death suggested the in-situ occurrence of gastric cancer under HP infection.     

Ki-67在胃癌及癌旁组织中的表达

目的:探讨Ki-67在胃癌和癌旁黏膜上皮中的表达、分布特征及其在胃癌组织发生学上的意义。方法:采用免疫组化方法对36例胃癌及癌旁组织进行检测。结果:胃腺癌与癌旁伴异型增生慢性萎缩性胃炎Ki-67阳性率无显著性差异;胃腺癌与癌旁伴高、中增殖型肠上皮化生慢性萎缩性胃炎Ki-67阳性率无显著性差异(P>0.05)。结论:Ki-67是一种较好的癌前标志物,胃黏膜上皮异型增生和高、中增殖型肠上皮化生萎缩性胃炎与胃癌的发生密切相关。     

Helicobacter pylori infection produces expression of a secretory component in gastric mucous cells

Helicobacter pylori infection induces the expression of a secretory component (SC) in gastric epithelial cells. We investigated the cell lineage of the SC- and immunoglobulin (Ig) A-expressing epithelial cells in H. pylori-infected gastric mucosa. Materials were obtained by means of gastric biopsy from H. pylori-infected patients (24 cases) before and after the eradication of H. pylori, from five normal uninfected volunteers, and from three gastrectomy cases. Acetic acid-ethanol-fixed and paraffin-embedded specimens were examined using histochemical staining for gastric mucins (periodic acid oxidation-thionine Schiff reaction-concanavalin A-horse radish peroxidase staining) by means of immunostaining for gastric mucins (45M1 and HIK1083), intestinal cells (MUC2 and CD10), Ki67, H. pylori, SC, and IgA. The SC and IgA were not found in normal gastric mucosa. The expressions of the SC and IgA in gastric surface mucous cells and mucous neck cells in the generating zone of the gastric mucosa of H. pylori-infected patients were significantly higher before eradication of H. pylori than after the eradication. These mucous cells have the potential for SC-mediated translocation of IgA into the gastric lumen, and this may act as part of the antibacterial defense system against H. pylori infection in the gastric generating zone.     

Time course of gastric mucosal changes in the assessment of long-term results of Helicobacter pylori eradication

The impact of Helicobacter pylori (H. pylori) eradication on the gastric mucosa (GM) was studied in patients with gastroduodenal ulcers. Clinical and morphological changes in the GM were assessed in 122 patients 3-7 years (mean 4.4 +/- 1.3 years) after eradication therapy and in 12 patients who had undergone H. pylori eradication. Successful H. pylori eradication in the gastric antral and body mucosa reduced inflammation, the degree of chronic inflammation, the number of lymphoid follicles, and the magnitude of gland atrophy. There were no statistically significant changes in intestinal metaplasia. The patients who had not received eradication therapy showed no significant GM changes as compared to the baseline values. In the unsuccessful eradication group, inflammation statistically significantly diminished in the gastric antrum and body with a reduction in the density of H. pylori contamination.     

Personalized treatment in the eradication therapy for Helicobacter pylori

Helicobacter pylori (HP) is known to be a causative bacterium of gastritis and peptic ulcers. The combination treatment consisting of a proton pump inhibitor (PPI), amoxicillin and clarithromycin (CAM) is widely used in eradication therapy, but the eradication fails in some patients. The main causes are CAM resistance of HP and individual variability in PPI metabolism related to the activity of the cytochrome P450 2C19 (CYP2C19) enzyme. In this study, we examined the usefulness of the prediction of the pharmacotherapeutic efficacy using a newly developed analysis system for HP CAM resistance and CYP2C19 genotypes. After obtaining the informed consent from 45 subjects with HP-positive peptic ulcers, biopsy specimens of the gastric mucosa were obtained by endoscopy. HP DNA extracted from the gastric mucosa was examined by the SELMAP-PCR method, the direct sequencing method or the single-nucleotide primer extension (SNuPE) method. HP detection rates by culture and the SELMAP-PCR method were 71% and 100%, respectively. Among 32 cultured HP, CAM resistance was confirmed in 6 samples by the in vitro drug susceptibility test. CAM-resistant gene mutations were also examined by the SELMAP-PCR method using 32 DNAs from cultured HP and the results were consistent with the drug susceptibility test. Among 22 patients, the eradication rate was 77%. Among 4 patients with CAM resistance determined by both the in vitro drug susceptibility test and the SNuPE method, eradication was successful in one intermediate metabolizer (IM), but not in three extensive metabolizers (EMs). Patients were divided into three groups according to their CYP2C19 phenotype: EMs, IMs and poor metabolizers (PMs). The eradication rates for 6 EMs, 12 IMs and 4 PMs were 33.3%, 91.7% and 100%, respectively. Based on these results, the information on CAM resistance in HP and CYP2C19 phenotypes in carriers could predict the pharmacotherapeutic efficacy and probability of eradication. It can then be possible to vary the dosing or to select another drug by the prediction of the pharmacotherapeutic efficacy.     

Helicobacter pylori and gastro-duodenal pathology

Helicobacter Pylori (HP) were found in 878 (73%) of 1205 patients undergoing upper G-I endoscopy with multiple biopsies for gastroduodenal diseases. HP were present in similar percentages among patients with active (89%) or healed (81%) peptic ulcer as well as in non ulcerous dyspeptics affected with gastritis (85%). 96% of active chronic gastritis were infected by HP as compared with 55% of quiescent gastritis. Antral gastritis was more frequently active in patients with ulcer diseases (76%) than in dyspeptic and asyntomatic patients (50%). Healed gastric and duodenal ulcers showed decreased incidence of active antral gastritis (69) as compared with active ulcers. Conversely body gastritis was more frequently active in healed (37%) than in overt (18%) duodenal ulcers. 95 histologically normal stomachs as well as 9 cases exhibiting type A gastritis were devoid of HP. High rates of infection were found in 610 cases of chronic gastritis without atrophy as well as in 151 atrophic antral (type B) gastritis. Cytoplasmic vacuolization and swelling of foveolar-superficial cells with adhering bacteria, micropapillae and microerosions were commonly found in HP-infected mucosa. In 16 of 19 children with type B chronic gastritis antibacterial therapy eradicated HP. This was followed by resolution or striking improvement of gastritis and disappearance of epithelial lesions.     

The relationship between persistent secretion of RANTES and residual infiltration of eosinophils and memory T lymphocytes after Helicobacter pylori eradication

Helicobacter pylori (HP)-infected gastric mucosa displays a conspicuous infiltration of mononuclear cells as well as neutrophils. RANTES is a potent chemoattractant peptide for memory T lymphocytes and eosinophils. RANTES protein concentration and the numbers of RANTES-, CD45RO-, and major basic protein (MBP)-positive cells were therefore evaluated in the gastric mucosa from 51 patients with HP-positive chronic gastritis before and after HP eradication and from 22 HP-negative healthy volunteers. RANTES protein concentration was significantly elevated in HP-positive cases and remained high after HP eradication. The numbers of RANTES-, CD45RO-, and MBP-positive cells were significantly increased in HP-positive cases and were well correlated with RANTES protein levels. All tended to decrease after HP eradication, but did not reach the level of HP-negative cases, even at 24 months after HP eradication. It was concluded that persistent expression and secretion of RANTES were closely related to residual infiltration of memory T lymphocytes and eosinophils, for a prolonged period after HP eradication. This seems to be an important mechanism of prolonged gastric mucosal immune response against HP infection, even after HP eradication, and of persistent mucosal damage and atrophy.     

Increase in proliferation and apoptosis of gastric epithelial cells early in the natural history of Helicobacter pylori infection.

Childhood acquisition of Helicobacter pylori is a critical risk factor for gastric cancer. Since tumorigenesis involves deregulation of proliferation and apoptosis, we examined gastric epithelial cell proliferation and apoptosis in H. pylori-infected children. Apoptosis and proliferation of gastric antral epithelial cells in biopsy specimens from patients with H. pylori-induced gastritis, secondary gastritis, and noninflamed controls were compared. p53 protein expression was examined immunohistochemically. Apoptotic cells were identified in the surface epithelium in each group. The apoptotic index was higher in specimens from patients with H. pylori gastritis (120 +/- 10) than secondary gastritis (50 +/- 10) and noninflamed controls (40 +/- 10, analysis of variance P < 0.005). Apoptosis decreased following H. pylori eradication and resolution of gastritis (P < 0.02). An expanded proliferative compartment was identified in H. pylori-induced gastritis (32.4 +/- 3.5; proliferative labeling index +/- SE) compared with secondary gastritis (18.9 +/- 2.8) and noninflamed controls (13.7 +/- 3.1, analysis of variance P < 0.01). The accelerated cell turnover was associated with p53 overexpression (analysis of variance P < 0.005). Accumulation of p53 was not associated with expression of the cyclin-dependent kinase inhibitor p21. The occurrence of altered cell turnover early in the natural history of chronic infection provides an explanation for the increased risk of gastric cancer development associated with childhood acquisition of infection.     

Association between genetic polymorphisms in the cyclooxygenase-1 gene promoter and peptic ulcers in Japan

Cyclooxygenase-1 (COX-1) has been regarded as a constitutively expressed enzyme that generates prostaglandins for gastrointestinal integrity. We attempted to clarify the association between potentially functional polymorphisms (T-1676C and A-842G/C50T) in the COX-1 gene promoter and gastroduodenal disorders in a Japanese population. The study was performed with 480 stocked DNAs from subjects (gastric ulcers in 93 subjects and duodenal ulcers in 44) with no evidence of gastric malignancy. We employed the PCR-SSCP method to detect gene polymorphisms. The severity of histological chronic gastritis in antral biopsy specimens was classified according to the updated Sydney system. The T-1676C polymorphism was not associated with either gastric mucosal atrophy or infiltration of inflammatory cells into gastric mucosa. In non-NSAID (non-steroidal anti-inflammatory drug) users, male gender and Helicobacter pylori (HP) infection were significantly associated with both gastric and duodenal ulcers, whereas the -1676T allele carrier was significantly associated with only gastric ulcers (OR, 2.86; 95% CI, 1.29-6.34). In NSAID users, the number of -1676T alleles was significantly associated with developing gastroduodenal ulcers (OR, 5.80; 95% CI, 1.59-21.1), whereas male gender and HP infection were not. The -842T/ C50T polymorphism was not detected in any of the 480 Japanese subjects. In conclusion, a carrier of the -1676T allele in the COX-1 gene promoter, as well as HP infection and male gender, seem to be significant risk factors for developing gastric ulcers, and the number of -1676T alleles was also a significant risk factor for the NSAID-induced ulcer, whereas the frequency of the A-842G polymorphism was thought to be very rare in the Japanese population.     

Enhanced cell kinetics, p53 accumulation and high p21WAF1 expression in chronic cholecystitis: comparison with background mucosa of gallbladder carcinomas

AIMS: Since neoplasia resulting from chronic inflammation has recently attracted increasing attention, we have investigated surgically removed gallbladders to examine the relationship between chronic cholecystitis and carcinogenesis. METHODS AND RESULTS: The mucosa of 108 cholecystectomy specimens without gallbladder cancer and 54 surgically resected gallbladder carcinomas were classified into three groups according to the degree of lymphocytic infiltration, and assessed immunohistochemically for Ki67, p53, p21WAF1 and apoptosis. In gallbladder mucosa without carcinoma, all four parameters tended to increase with the inflammation score (IS). Significantly positive correlations were revealed between Ki67 and p53, Ki67 and p21WAF1, and p53 and p21WAF1. However, in gallbladder carcinoma cases, values of p53 and p21WAF1 for background mucosa were elevated as compared to the mucosa of cholecystitis with low IS, but there was no correlation between their expression and IS, except for Ki67. CONCLUSIONS: Severe chronic cholecystitis is associated with acceleration of epithelial cell turnover, damaged cells being eliminated by apoptosis. The background mucosa of gallbladder carcinomas showed similar cell proliferative activity (Ki67) to that in cholecystitis, with no parallel changes of p53 and p21WAF1 expression, suggesting the possibility of unknown cofactors causing genomic damage.     

Immunohistochemical study of DNA topoisomerase II in human gastric disorders.

Topoisomerase II (topo II) separates chromosomes at the end of mitosis and is also the target for various chemotherapeutic agents. Expression of this enzyme has been demonstrated to increase rapidly at the end of the S to G2/M phase and decrease after the completion of mitosis. We immunolocalized topo II in specimens of both normal and neoplastic human gastric mucosas to evaluate expression of this enzyme. Three different antibodies were used for the immunostaining of topo II (anti-topo II alpha isoform, anti-topo II beta isoform and anti-topo II alpha and -beta isoforms). There were no significant differences in topo II labeling index (LI) between frozen and paraffin-embedded tissue sections obtained from the same cases. Topo II LI was significantly correlated with Ki67 LI in all of the specimens examined. The area of cells positive for Topo II was much narrower than that of Ki67 in the normal gastric glands, and the pattern of Topo II immunolocalization in both adenomas and adenocarcinomas was also essentially the same as that of Ki67. The topo II LI values (positive cells/1000 cells) for normal gastric gland, adenoma, intestinal-type adenocarcinoma, and diffuse-type adenocarcinoma were 114.7 +/- 2.2, 266.7 +/- 18.8, 277.6 +/- 19.2, and 324.5 +/- 5.3, respectively. Significant differences in topo II LI and topo II/Ki67 index were observed between normal and neoplastic mucosas (P < 0.0001) and between adenomas or intestinal-type adenocarcinoma and diffuse-type adenocarcinoma (P < 0.001 and P < 0.01, respectively). Simultaneous measurement of topo II alpha and nuclear DNA content by two-parameter flow cytometry revealed that the Jurkat cell line established from acute lymphocytic leukemia cells expressed the enzyme in cells at other than S and G2/M phases of the cell cycle whereas topo-II alpha-positive cells were predominantly observed in S and G2/M phases of the cell cycle in the cells from normal lymph nodes. These findings suggest that dys-regulation or qualitative changes of topo II alpha expression are associated with malignancy. Topo II immunostaining can thus detect proliferating cells in routinely processed tissue sections and can indicate the altered topo II alpha expression in human cancers, which may be related to the sensitivity to topo-II-targeted chemotherapeutic agents.     

Decreased gastric proliferation of foveolar epithelial cells after the eradication of Helicobacter pylori.

Increased epithelial cell proliferation is associated with an increased risk of gastric carcinoma. Helicobacter pylori infection is an established risk factor for gastric cancer and the organism has recently been classified as a group I carcinogen by an IARC working group. In this study, we describe differences in gastric epithelial cell proliferation between a H. pylori eradicated group (n = 21) and a not eradicated group (n = 8) after anti-H. pylori eradication therapy to show that increased cell proliferation is associated with H. pylori infection. H. pylori infection was determined by rapid urease test and immunohistochemical method with anti-H. pylori polyclonal antibody. Gastric epithelial cell proliferation was assessed using immunohistochemical method using Ki-67 monoclonal antibody. Ki-67 positive cells in H. pylori associated chronic active gastritis were observed in the glandular neck and the upper portion of foveolar epithelium. Patients who cleared their H. pylori infections showed a significant decrease of Ki-67 labeling index after therapy (0.73 +/- 0.10 vs. 0.48 +/- 0.08, p < 0.01). By contrast, Ki-67 labeling index before and after treatment in patients who remained positive for H. pylori showed no significant difference (0.78 +/- 0.08 vs 0.74 +/- 0.10, p > 0.05). These results indicate that H. pylori infection increases the proliferation of gastric foveolar epithelium, which is reduced by the eradication therapy. We suggest that anti-H. pylori eradication therapy can prevent mucosal cell proliferation to be closely associated with gastric carcinogenesis.     

p53, but not c-Ki-ras, mutation and down-regulation of p21WAF1/CIP1 and cyclin D1 are associated with malignant transformation in gastric hyperplastic polyps

To investigate tumorigenesis in the gastric hyperplastic polyp (HP), we evaluated 19 HPs with and 50 HPs without dysplasia (including carcinoma in situ), as compared with normal mucosa and fundic gland polyps. Helicobacter pylori density was highest in HPs without dysplasia. Apoptotic activity and Ki-67 and p53 expression also were higher in dysplasia in HPs than in normal mucosa, fundic gland polyps, or HPs themselves. The p21WAF1/CIP1 and cyclin D1 levels, in contrast, were highest in HPs. In HPs without dysplasia, size was correlated positively with the degree of stromal inflammation and with p53 and cyclin D1 expression. p53 and c-Ki-ras mutations were detected in 41% (8/19) and 5% (1/19) of dysplasia (including carcinoma in situ) in HPs. Our results demonstrate that the HP enlarges with enhanced cell turnover and overexpression of p53, p21WAF1/CIP1, and cyclin D1, associated with H pylori-related inflammation, and that p53 but not c-Ki-ras mutations may have an important role in dysplastic change in HPs.