PTEN encoding product： a marker for tumorigenesis and progression of gastric carcinoma

AIM: To detect the expression of PTEN encoding productin normal mucosa, intestinal metaplasia (IM), dysplasia andcarcinoma of the stomach, and to investigate its clinicalimplication in tumorigenesis and progression of gastriccarcinoma.METHODS: Formalin-fixed paraffin embedded specimens from184 cases of gastric carcinoma, their adjacent normal mucosa,IM and dysplasia were evaluated for PTEN protein expressionby SABC immunohistochemistry. PTEN expression wascompared with tumor stage, lymph node metastasis, Lauren'sand WHO's histological classification of gastric carcinoma.Expression of VEGF was also detected in 60 cases of gastriccarcinoma and its correlation with PTEN was concerned.RESULTS: The positive rates of PTEN protein were 100 %(102/102), 98.5 %(65/66), 66.7 % (4/6) and 47.8 %(88/184)in normal mucosa, IM, dysplasia and carcinoma of the stomach,respectively. The positive rates in dysplasia and carcinomawere lower than in normal mucosa and IM (P＜0.01).Advanced gastric cancers expressed less frequent PTEN thanearly gastric cancer (42.9 % v567.6 %, P＜0.01). The positiverate of PTEN protein was lower in gastric cancer with thanwithout lymph node metastasis (40.3 % v563.3 %, P＜0.01).PTEN was less expressed in diffuse-type than in intestinal-type gastric cancer (41.5 % v557.8 %,P＜0.05). Signet ringcell carcinoma showed the expression of PTEN at the lowestlevel (25.0 %, 7/28); less than well and moderatelydifferentiated ones (P＜0.01). Expression of PTEN was notcorrelated with expression of VEGF (P＞0.05).CONCLUSION: Loss or reduced expression of PTEN proteinoccures commonly in tumorigenesis and progression of gastriccarcinoma. It is suggested that PTEN can be an objective markerfor pathologically biological behaviors of gastric carcinoma.     

长期饮酒合并幽门螺杆菌感染时胃黏膜损伤程度与EGF和PGE2的关系

目的探讨长期饮酒合并幽门螺杆菌感染时胃黏膜损伤的程度与胃液及血液中EGF及PGE2之间的关系。方法对2007年1月～2010年12月符合条件的长期饮酒合并幽门螺杆菌感染的56例患者进行内镜下胃黏膜活检组织的病理学观察,同时抽静脉血及胃液用ELISA法检测EGF及PGE2浓度。结果长期饮酒合并幽门螺杆菌感染胃黏膜中重度慢性炎症组患者血清和胃液EGF浓度明显高于轻度慢性炎症组患者血清和胃液EGF浓度(P=0.000;P=0.018);胃黏膜中重度萎缩组患者血清EGF浓度明显高于胃黏膜轻度萎缩组患者血清EGF浓度(P=0.000);胃黏膜中重度肠化组患者血清EGF浓度明显高于胃黏膜胃黏膜轻度肠化组患者血清EGF浓度(P=0.000),而胃黏膜中重度肠化组患者血清PGE2浓度明显降低(P=0.034);胃黏膜有不典型增生组患者血清和胃液中EGF浓度明显高于胃黏膜无不典型增生组患者血清和胃液中EGF浓度(P=0.000;P=0.044)。结论长期饮酒合并幽门螺杆菌感染引起血液中EGF升高与患者胃黏膜慢性炎症、萎缩和肠化加重及不典型增生的发生有关。而胃液中EGF浓度的升高仅与胃黏膜慢性炎症和不典型增生发生相关。在胃黏膜肠化患者中血清中PGE2明显降低。     

Apoptotic cell death and its relationship to gastric carcinogenesis

AIM: To investigate the apoptotic process of cells with in the intestinal metaplasia areas co-localizing with chronic gastritis and gastric carcinomas and to analyze the involvement of proteins regulating apoptosis in the process of intestinal metaplasia related gastric carcinogenesis. METHODS: Forty-two gastric carcinoma and seventeen chronic gastritis cases were included in this study. All cases were examined for the existence of intestinal metaplasia. Ten cases randomly selected from each group were processed for TUNEL assay. TUNEL positive cells within the intestinal metaplasia areas, co-localizing either to gastric carcinoma or chronic gastritis, were counted and converted to apoptotic indices. In addition, p53, bcl-2 and bax expression patterns within these tissues were analyzed on the basis of immunohistochemistry. RESULTS: Twenty-eight of the cases were intestinal and 14 of the cases were diffuse type adenocarcinomas. 64% (27/42) of the gastric carcinoma cases had intestinal metaplasia. Intestinal metaplasia co-localized more with intestinal type carcinomas compared with diffuse type carcinomas [75% (21/28) vs 42% (6/14), respectively; P ≤0.05]. The mean apoptotic index in tumor cells was 0.70±0.08. The mean apoptotic index in intestinal metaplasias co-localizing to tumors was significantly higher than that of intestinal metaplasias co-localizing to chronic gastritis (0.70±0.03 vs 0.09±0.01, respectively; P≤0.05). p53 positivity was not observed in areas of intestinal metaplasia adjacent to tumors or chronic gastritis. Intestinal metaplasia areas adjacent to tumors showed lower cytoplasmic bcl-2 positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [55.5% (15/27) vs 70.5% (12/17), respectively]. On the other hand, intestinal metaplasia areas adjacent to tumors showed significantly higher cytoplasmic bax positivity compared to intestinal metaplasia areas adjacent to chronic gastritis [44.4% (12/27) vs 11.7% (2/17), respectively; P ≤0.05]. CONCLUSION: Existence of apoptotic cells on the basis of TUNEL positivity is shown in intestinal metaplasias co-localizing to both diffuse and intestinal type gastric cancers in this study. Our results also suggested bax expression dependent induction of apoptosis especially in intestinal metaplasia areas adjacent to tumors. These findings strongly support the involvement of apoptotic mechanisms in the process of gastric carcinogenesis especially in the transition from intestinal metaplasia to gastric cancer. It may be suggested that induction of apoptosis in intestinal metaplasia areas adjacent to tumors may involve different mechanisms than induction by chronic inflammation.     

胃癌及癌前病变中p53蛋白的检测及意义

探讨p53蛋白表达与胃癌及癌病变的相互关系,方法：用免疫组化染色示检测33例肠化,26例异型增生和26例胃癌组织中p53蛋白的表达。结果：p53蛋白在胃癌组织中表达率最高（61．5％）,在异型增生和肠化组织中的表达率分别为34．6％和12．1％,组间有显著差异,各期胃癌组织中p53蛋白的表达无显著差异,结论：p53蛋白在胃癌前病变中已有阳性表达,在肠化、异型增生及胃癌组织中,其表达率依次增高,p53蛋白积累主要发生在癌前病变晚期及胃癌早期,其表达与胃癌发生密切相关。     

Is NEDD4-1 a negative regulator of phosphatase and tensin homolog in gastric carcinogenesis?

The expression of phosphatase and tensin homolog (PTEN), a tumor suppressor gene, is frequently down-regulated in gastric carcinomas due to mutation, loss of heterozygosity, and promoter hypermethylation. However, it is unknown if additional mechanisms may account for the down-regulation of PTEN expression. While neuronal precursor cell-expressed developmentally down-regulated 4-1 (NEDD4-1) is believed to be a potential dual regulator of PTEN, there are conflicting reports regarding their interaction. To gain further insight into the role of NEDD4-1 and its association with PTEN in gastric carcinoma development, we measured the protein expression of NEDD4-1 and PTEN in gastric mucosae with various pathological lesions and found that NEDD4-1 increased from normal gastric mucosa to intestinal metaplasia and decreased from dysplasia to gastric carcinoma. These changes did not correlate with PTEN expression changes during gastric carcinogenesis. Moreover, we found similar results in protein levels in the primary tumors and adjacent non-tumorous tissues. These results differ from a previous report showing that expression of NEDD4-1 is up-regulated in gastric carcinomas, and show a more complex pattern of NEDD4-1 gene expression during gastric carcinogenesis.     

胃癌组织中MTA1,PTEN,E-cadherin的表达及其相互关系

目的:观察MTA1,PTEN,E-cadherin蛋白在胃癌和正常胃黏膜组织中的表达,探讨其与胃癌浸润、转移和生物学行为的关系.方法:应用免疫组织化学方法检测54例胃癌手术切除标本和15例正常胃黏膜组织中MTA1,PTEN,E-cadherin的表达.各指标之间相关因素的差异性比较采用χ2检验,相关性研究采用Spearman相关分析:结果:与正常胃组织相比,MTA1蛋白在胃癌组织中高表达(46.3% vs 6.7%,P＜0.01),PTEN和E-cadherin蛋白在胃癌组织中表达下调或缺失(51.9% vs 100%,42.6% vs 100%,均P＜0.01).MTA1和PTEN的阳性表达率与肿瘤浸润深度(P=0.003,P=0.001)、病理分期(P=0.004,P=0.008)、淋巴转移(P=0.000,P=0.001)、远隔转移(P=0.004,P=0.006)、临床分期有关(P=0.001,P=0.000);E-cadherin的正常表达率与肿瘤浸润深度(P=0.027)、病理分化程度(P=0.006)、淋巴转移(P=0.044)、临床分期有关(P=0.000).Spearman相关分析显MTA1与PTEN蛋白、MTA1与E-cadherin蛋白的表达呈负相关(r=-0.518,r=-0.424,均p＜0.05).PTEN蛋白与E-cadherin蛋白的表达呈正相关(r=0.53,P＜0.05).结论:MTA1蛋白水平高表达和PTEN,E-cadherin蛋白水平低表达可能与胃癌浸润和转移有关,且联合检测可以用于判断胃癌的生物学行为.     

胃癌及其癌前病变中细胞凋亡与细胞增殖间关系的研究

目的　通过观察胃癌及其癌前病变中细胞凋亡与细胞增殖间的关系,探讨细胞凋亡在胃癌发生中的作用．方法　利用脱氧核糖核酸末端转移酶介导的ｄ ＵＴＰ 缺口末端标记（ＴＵＮＥＬ） 技术及增殖细胞核抗原（ ＰＣＮＡ） 免疫组织化学染色对１０ 例正常胃粘膜、１６ 例萎缩性胃炎、３６ 例肠化生、２０ 例异型增生和５３ 例胃癌中的凋亡细胞、增殖细胞进行原位观察和比较．结果　萎缩性胃炎、肠化生、异型增生中凋亡细胞指数（１１－９ ％ ;１４－７ ％ ,８－０ ％ ） 均显著高于正常胃粘膜和 胃癌（３－５ ％ ,５－８ ％ ,ｔ ＝ ２－０５８ ～７－９０１ ,Ｐ＜ ０－０１ ～Ｐ ＜ ０－０５） ;异型增生、胃癌与肠化生相比,凋亡细胞明显减少、增殖细胞明显增多（ Ｐ＜ ０－０５） ;胃癌细胞增殖指数（４７－５ ％ ） 显著高于异型增生（３０－１ ％ ,Ｐ＜ ０－０１） ． 胃癌前病变及胃癌组织中的凋亡细胞指数与 增 殖细 胞指 数 呈显 著相 关（ ｒ ＝ ０－９６６ , － ０－８９７ ,Ｐ＜ ０－０５） ．结论　胃粘膜癌变过程中不仅存在活跃的细胞增殖,而且存在细胞凋亡异常． 高增殖能力的细胞可能通过选择而占据优势,导致胃癌的发生． 细胞凋亡与细胞增殖平衡失调在胃癌发病中可能起重要作用     

CD44v6: a potential marker of malignant transformation in intestinal metaplasia of the stomach? An immunohistochemical study using tissue microarrays

OBJECTIVE: Intestinal metaplasia is a well-established risk factor in the development of stomach cancer. However, since the specificity is low it would be of great practical value to find a marker to separate cases of intestinal metaplasia into low and high risk for progression to dysplasia/carcinoma. So far this has not been achieved. CD44 is a cell surface molecule involved in cell-cell and cell-matrix interactions, and the spliced variant 6 has been shown to play a role in the progression of gastric carcinoma. The aim of this study was therefore to evaluate CD44v6 as a marker of increased cancer risk in intestinal metaplasia. METHODS: The current study investigated immunohistochemical CD44v6 expression in biopsies of normal gastric mucosa (n = 154) and gastric mucosa with intestinal metaplasia (n = 127). A third group consisted of cancer gastrectomies (n = 117) in which both tumour and uninvolved mucosa was studied. Proximal (cardia) and distal (corpus/antrum) locations were noted in all cases. RESULTS: There was a significant sequential increase in CD44v6 expression from normal mucosa and mucosa showing intestinal metaplasia to uninvolved mucosa adjacent to cancers without and with intestinal metaplasia to tumour. The most striking increase was from 'normal' to intestinal metaplastic mucosa adjacent to cancers. There were no differences between proximal and distal cases in any group. CONCLUSION: These findings strongly suggest that CD44v6 expression is a late phenomenon in the transformation of intestinal metaplasia to dysplasia/cancer. It may therefore be a useful marker of cancer risk in patients with intestinal metaplasia.     

Expression of MUC2 in gastric carcinomas and background mucosae

BACKGROUND AND AIM: Gastric carcinomas contain elements of both intestinal and diffuse types. Such heterogeneous components may distort the evaluation of the role of the mucin MUC2 in gastric carcinoma. The role of MUC2 expression in background mucosa is not yet clarified. METHODS: We analyzed the expression of MUC2 in gastric mucosa and intestinal metaplasia adjacent to the tumoral area and carcinomas (n = 98) using immunohistochemistry. The immunoreactivity was quantified using an immunohistochemical scoring system. RESULTS: In the intestinal metaplasia adjacent to the tumoral area, MUC2 was detected in 76 (97.4%) of 78 intestinal metaplasia, and MUC2 expression was inversely associated with the depth of wall penetration (P = 0.026) and tumor stage (P = 0.021). Although the expression rate of MUC2 antigens was higher in intestinal-type adenocarcinoma than in diffuse-type adenocarcinoma, a significant correlation with pathologic staging of the TNM system (pTNM staging) and MUC2 expression could not be found in each subtype of gastric carcinomas. CONCLUSION: The expression of MUC2 in intestinal metaplasia was higher in tumors of earlier stages. These findings suggest that increased MUC2 expression in intestinal metaplasia in the neighborhood of the carcinomas may play an important role in gastric carcinomas. Further investigations regarding the role of MUC2 expression in gastric carcinoma and background mucosae are necessary.     

Clinical significance of expression of proliferating cell nuclear antigen and E-cadherin in gastric carcinoma

AIM to investigate the expression of proliferating cell nuclear antigen(p CNA)and E-cadherin in gastric carcinoma and to analyze their clinical significance.METHODS A total of 146 patients were selected for this study,including 38 patients with intestinal metaplasia,42with dysplasia,and 66 with primary gastric cancer.In addition,40 patients with normal gastric tissues were selected as controls.the expression of p CNA and E-cadherin was detected by immunohistochemistry.Differences in p CNA and the E-cadherin labeling indexes among normal gastric mucosa,intestinal metaplasia,dysplasia,and gastric carcinoma were compared.Subjects with normal gastric tissues were assigned to a normal group,while gastric cancer patients were assigned to a gastric cancer group.the difference in p CNA and E-cadherin expression between these two groups was compared.the relationship between expression of p CNA and E-cadherin and clinicopathological features was also explored in gastric cancer patients.furthermore,prognosis-related factors,as well as the expression of p CNA and E-cadherin,were analyzed in patients with gastric cancer to determine the 3-year survival of these patients.RESULTS the difference in p CNA and the E-cadherin labeling indexes among normal gastric mucosa,intestinal metaplasia,dysplasia,and gastric carcinoma was statistically significant(p0.05).During the transition of normal gastric mucosa to gastric cancer,the p CNA labeling index gradually increased,while the E-cadherin labeling index gradually decreased(p0.05).the p CNA labeling index was significantly higher and the E-cadherin labeling index was significantly lower in gastric cancer than in dysplasia(p0.05).the expression of p CNA was significantly higher in the gastric cancer group than in the normal group,but E-cadherin was weaker(p0.05).there was a negative correlation between the expression of p CNA and E-cadherin in gastric carcinoma(r=-0.741,p=0.000).p CNA expression differed significantly between gastric cancer patients with and without lymph node metastasis and between patients at different t stages.E-cadherin expression also differed significantly between gastric cancer patients with and without lymph node metastasis(p0.05).High t stage and positive p CNA expression were risk factors for the prognosis of patients with gastric cancer(RR1),while the positive expression of E-cadherin was a protective factor(RR1).the sensitivity,specificity,and accuracy of p CNA positivity in predicting the 3-year survival of patients with gastric cancer were 93.33%,38.89%,and0.64,respectively;while these values for E-cadherin negativity were 80.0%,41.67%,and 0.59,respectively.When p CNA positivity and E-cadherin negativity were combined,the sensitivity,specificity,and accuracy were66.67%,66.67%,and 0.67,respectively.CONCLUSION Combined detection of p CNA and E-cadherin can improve the accuracy of assessing the prognosis of patients with gastric cancer.     

胃癌前组织和胃癌中hTERT、Bcl-2蛋白的表达及其相互关系

目的 探讨胃癌前组织及胃癌中人端粒酶催化亚单位(human telomerase catalytic subunit,hTERT)的表达状况及其与Bcl-2蛋白表达的关系。方法 应用免疫组织化学技术检测45例慢性胃炎和19例胃癌中hTERT和Bcl-2蛋白的表达。结果 hTERT蛋白表达率在萎缩性胃炎、肠化生、异形增生和胃癌等不同胃黏膜癌变过程中呈递增趋势;hTERT蛋白的表达率在胃癌组织中显著高于异形增生、肠化生和萎缩性胃炎组织(P<0.05);在异形增生组织中显著高于肠化生和萎缩性胃炎组织(P<0.05);在肠化生组织中显著高于萎缩性胃炎组织(P<0.05)。Bcl-2蛋白表达率在萎缩性胃炎、肠化生、异形增生和胃癌等不同胃黏膜癌变过程中呈递增趋势;Bcl-2蛋白的表达率在胃癌组织中显著高于异形增生、肠化生和萎缩性胃炎组织(P<0.05);在异形增生组织中显著高于萎缩性胃炎组织(P<0.05),亦高于肠化生,但是相差无显著性;在肠化生组织中显著高于萎缩性胃炎组织(P<0.05)。Bel-2蛋白阳性患者hTERT蛋白表达率为71.43％,Bcl-2蛋白阴性患者hTERT蛋白表达率34.44％,hTERT蛋白表达率在Bcl-2蛋白阳性患者中显著高于Bcl-2蛋白阴性患者(P<0.01)。结论 在胃癌和胃癌前病变阶段,端粒酶(telomerase)与Bcl-2均可能发挥重要作用,促进了胃癌的发生、发展;Bcl-2表达增加可能是胃     

Apoptosis, proliferation and p53 gene expression of H. pylori associated gastric epithelial lesions

AIM:To study the relationship between Helicobacter pylori(H.pylori)and gaatric carcinoma and its possiblepathogenesis by H.pylori.METHODS:DNEL technique and immunohistochemicaltechnique were used to study the state of apoptosis,proliferation and p53 gone expression.A total of 100 gastricmucosal biopsy specimens,including 20 normal mucosa,30H.pylori-negative and 30 H.pylori-positive gastricprecancerous lesions along with 20 gastric carcinomas werestudied.RESULTS:There were several apoptotic cells in thesuperficial epithelium and a few proliferative cells within theneck of gestric glands,and no p53 protein expression innormal mucosa.In gestric carcinoma,there ware fewapoptotic cells,while there were a large number ofproliferative cells,and expression of p53 proteinsignificantly was increased.In the phase of metaplasia,theapoptotic index(Al,4.36%±1.95%),proliferative index(Pl,19.11%±6.79%)and positivity of p53 expression(46.7%)in H.pylori-positive group ware higher than thosein normal mucosa(P<0.01).Al in H.pylori-positive groupwas higher than that in H.pylori-negative group(3.81%±1.76%),Pl in H.pylori-positive group was higher than thatin H.pylori-negative group(12.23%±5.63%,P<0.01).Inthe phase of dysplasia,Al(2.31%±1.10%) in H.pylori-positive group was lower(3.05%±1.29%)than that in H.pylori-negative group,but Pl(33.89%±11.65%)wassignificantly higher(22.09±8018%,P<0.01).In phases ofmetaplasia,dysplasia and gastric cancer in the H.pylori-positive group,Als had an evidently greduall decreasingtrend(P<0.01),while Pls had an evidently gradualincreasing trend(P<0.05 or P<0.01),and there was alsoa trend of gradual increase in the expression of p53 gone.CONCLUSION:In the course of the formation of gastriccarcinoma,proliferation of gastric mucosa can be greatlyIncreased by H.pylori,and H.pylori can induce apoptosisin the phase of metaplasia,but in the phase of dysplesia H.pylorl can inhibit cellular apptosis.And H.pylori infectioncan strengthen the expression of mutated p53 gene.     

Growth,invasion, metastasis,differentiation, angiogenesis and apoptosis of gastric cancer regulated by expression of PTEN encoding products

AIM: To investigate expression of PTEN in gastric cancer and to explore its roles in tumorigenesis and progression of gastric cancer.METHODS: Formalin-fixed and paraffin-embedded tissues of adjacent non-tumor mucosa and primary foci from 113cases of gastric cancers were studied for the expression of PTEN and Caspase-3 andmicrovessel density (MVD)by streptavidin-peroxidase (S-P) immunohistochemistry with antibodies against PTEN, Caspase-3, and CD34. The relationship between PTEN and Caspase 3 expression and clinicopathological parameters of tumors was compared.RESULTS: Primary gastric cancer cells expressed PTEN less frequently than adjacent epithelial cells of primary foci (54.9％ vs89.4％; P=0.000, χ2=33.474). PTEN expression was significantly associated with invasive depth (P=0.003,rs=0.274), metastasis (P=0.036, rs=0.197), growth pattern (P=0.008, rs=0.282), Lauren′s classification (P=0.000,rs=0.345), and histological classification (P=0.005, rs=0.262)of tumors, but not with tumor size (P=0.639, rs=0.045),Borrmann′s classification (P=0.544, rs=0.070) or TNM staging (P=0.172, rs=0.129). PTEN expression was negatively correlated with MDV in primary gastric cancer (P=0.020,F=5.558). Primary gastric cancer cells showed less frequent immunoreactivity to Caspase-3 than adjacent epithelial cells of primary foci (32.7 ％ vs 50.4 ％; P=0.007,χ2=7.286).Caspase-3 expression was dependent of PTEN expression in primary gastric cancer cells (P=0.000, χ2=15.266).CONCLUSION: Down-regulated expression of PTEN plays an important role in tumorigenesis, progression, growth,differentiation and angiogenesis of gastric cancer. Low expression of PTEN can decrease expression of Caspase-3to disorder apoptosis of tumor cells, which might explain the molecular mechanisms of PTEN contributions to tumorigenesis and progression of gastric cancer.     

慢性萎缩性胃炎黏膜上皮中P53和C-erbB-2表达的临床意义

目的:探讨慢性萎缩性胃炎(CAG)黏膜上皮中P53及C-erbB-2的表达及意义．方法:用免疫组化技术(SP法)检测正常胃黏膜56例、慢性萎缩性胃炎429例(腺体囊性扩张61例,大肠型化生73例,轻、中、重度不典型增生各120、91和84例)和早期胃癌57例中P53和C-erbB-2的表达,分析P53和C-erbB-2表达及其与CAG胃黏膜病变类型的关系．结果:正常胃黏膜,囊性扩张腺体,轻、中度不典型增生,大肠型化生,重度不典型增生,早期胃癌P53和C-erbB-2表达的阳性率呈上升趋势．前三组间表达率差异无统计学意义(P>0．05);正常胃黏膜与中度不典型增生、大肠型化生、重度不典型增生及胃癌组P53和C-erbB-2的表达差异有统计学意义(P<0．01)．Spearman等级相关分析显示P53和C-efbB-2表达呈正相关(r=0．867,P<0．05)．年龄<40岁和≥40岁组间、性别组间P53表达阳性率差异有统计学意义(x2=12．393,P<0．01;x2=8．799, P<0．01)．C-erbB-2的表达在上述年龄组间差异有统计学意义(x2=7．706,P<0．01),而在性别组间无统计学意义(P>0．05)．结论:检测慢性萎缩性胃炎中P53和C-erbB-2的表达,有助于监测CAG癌前病变的进展及胃癌的早期发现．     

Mutant p53 expression and apoptotic activity of Helicobacter pylori positive and negative gastritis in correlation with the presence of intestinal metaplasia

BACKGROUND: Mutation of the p53 gene is detectable in most cases of gastric cancer, as it is the most common genetic alteration in human malignancies. It is also well documented that Helicobacter pylori infection plays an important role in gastric carcinogenesis. There is still no clarification, however, concerning how genetic instability influences the homeostasis of gastric epithelium. We have studied the effect of H. pylori infection on apoptosis of the antral epithelium in the presence/absence of intestinal metaplasia and the expression of the p53 oncoprotein. The relationship between these two processes is analysed. METHODS: Antral biopsies were taken from 36 patients who underwent routine upper endoscopy (17 men, 19 women, mean age 61.0 years). The biopsies were fixed in formalin and embedded in paraffin. Patients were classified into two histological groups: (1) as chronic gastritis without intestinal metaplasia (n = 19), and (2) chronic gastritis with intestinal metaplasia (n = 17). An immunohistochemical method was used to detect the expression of p53 oncoprotein, and the terminal transferase mediated dUTP nick end-labelling (TUNEL) method was used to detect apoptotic cells. RESULTS: In the absence of intestinal metaplasia, both the apoptotic index (0.0272 +/- 0.011 vs 0.0128 +/- 0.006) and expresssion of p53 (35.55 +/- 31.16 vs 18.33 +/- 19.65) were significantly higher in H. pylori positive cases compared to H. pylori negative cases. In the presence of intestinal metaplasia, p53 expression was further increased (P < 0.05), but apoptosis was similar to that observed in H. pylori negative gastritis without intestinal metaplasia. In the presence of intestinal metaplasia, H. pylori infection did not influence apoptosis (0.013 +/- 0.004 vs 0.011 +/- 0.004), or p53 ratio (70.16 +/- 22.54 vs 68.50 +/- 28.96). In the sequence of gastritis-intestinal metaplasia the two indices show a close negative correlation (P < 0.05). CONCLUSION: In the absence of intestinal metaplasia H. pylori infection increases both apoptotic activity and expression of p53 oncoprotein in the gastric mucosa. The lack of increased apoptosis with a higher p53 expression in the presence of intestinal metaplasia suggests an increased genetic instability and also may suggest that mutation of the p53 gene is an early step in the multistep process of gastric carcinogenesis.     

Expression of TFF2 and Helicobacter pylori infection in carcinogenesis of gastric mucosa

AIM: To investigate the expression of TFF2 and Helicobacter pyloriinfection in carcinogenesis of gastric mucosa.METHODS: The expression of TFF2 was immunohistochemically analyzed in paraffin-embedded samples from 119 patients with endoscopic biopsy and subtotal gastrectomy specimens of gastric mucosal lesions, including 16 cases of chronic superficial gastritis (CSG), 20 chronic atrophic gastritis (CAG),35 intestinal metaplasia (IN), 23 gastric epithelial dysplasia (GED) and 25 gastric carcinoma (CA), and Helicobacter pylori infection was detected by Warthin-Starry staining.RESULTS: 1:TFF2 was located in the cytoplasm of gastrk mucous neck cell. The expression of TFF2 was 100 %,100 %, 0, 56.5 % and 0 in CSGs, CAGs, INs, GEDs and CAs, respectively. 2: The value of TFF2 positive cell density in CSG with Helicobacter pyloriinfection was higher than that without Helicobacter pyloriinfection. (52.89±7.27vs46.49±13.04, P＞0.05); But the value of TFF2 positive cell density in CAG and GED with Helicobacter pyloriinfection was significantly lower than that without Helicobacter pylori infection (18.17±4.09 vs 37.93±13.80, P＜0.01 and 14.44±9.32 vs 24.84±10.22, P＜0.05).CONCLUSION: Increase of TFF2 expression in CSG is perhaps associated with the protective mechanism after gastric mucosal injury. Decrease of TFF2 expression in CAG possibly attributes to the decrease in the number of gastric gland cell expressing TFF2. Re-expression of TFF2 in gastric epithelial dysplasia implies that TFF2 possibly contributes to the initiation of gastric carcinoma. The effect of Helicobacter pylori on the expression of TFF2 depends on the status of gastric mucosa.     

Tumor metastasis and the reciprocal regulation of heparanase gene expression by nuclear factor kappa B in human gastric carcinoma tissue

AIM: To investigate whether NF-kB is activated in human gastric carcinoma tissues and, if so, to study whether there is any correlation between NF-kB activity and heparanase expression in gastric carcinoma. METHODS: NF-kB activation was assayed by immunohistochemical staining in formalin-fixed, paraffin-embedded specimens from 45 gastric carcinoma patients. Electrophoretic mobility shift assay (EMSA) method was used for nuclear protein from these fresh tissue specimens. Heparanase gene expression was quantified using quantitative RT-PCR. RESULTS: The nuclear translocation of RelA (marker of NF-kB activation) was significantly higher in tumor cells compared to adjacent and normal epithelial cells [(41.3±3.52)% vs (0.38±0.22) %, t=10.993, P= 0.000<0.05; (41.3±3.52)% vs(0±0.31)%, t=11.484, P= 0.000<0.05]. NF-kB activation was correlated with tumor invasion-related clinicopathological features such as lymphatic invasion, pathological stage, and depth of invasion (Z= 2.148, P= 0.032<0.05; t = 8.758, P= 0.033<0.05; t = 18.531, P = 0.006<0.05). NF-KB activation was significantly correlated with expression of heparanase gene (r= 0.194, P=0.046<0.05). CONCLUSION: NF-KB RelA (p65) activation was related with increased heparanase gene expression and correlated with poor clinicopathological characteristics in gastric cancers. This suggests NF-kB as a major controller of the metastatic phenotype through its reciprocal regulation of some metastasis-related genes.