原位杂交方法检测胃癌及其癌前病变中抑癌基因p53的表达

目的用原位杂交方法检测胃粘膜癌前病变及胃癌组织中ｐ５３ｍＲＮＡ的表达,并观察感染Ｈｐ对其表达的影响．方法病理证实为慢性胃炎６６例和胃癌１６例,用地高辛标记的ｃＤＮＡ为探针进行原位杂交实验,检测其胃粘膜组织中ｐ５３ｍＲＮＡ表达,用单克隆抗体ＤＯ０１进行免疫组化检测Ｐ５３蛋白的表达．结果在慢性萎缩性胃炎、肠化生、异型增生及胃癌中,原位杂交方法检测ｐ５３ｍＲＮＡ表达率分别为５３９％,５２３％,４２８％和２５％,免疫组化方法检测Ｐ５３蛋白的表达率分别为００％,５３％,１５４％和２５％．ｐ５３ｍＲＮＡ的表达与蛋白的表达无明显的一致性,ｐ５３ｍＲＮＡ的表达可以在Ｐ５３蛋白阴性及阳性的细胞中．在２６例萎缩性胃炎中,１４例检测到ｐ５３ｍＲＮＡ的表达,而其中１６例（包括１４例阳性病例）无一例检测到Ｐ５３蛋白的表达．在肠化生、异型增生及胃癌组织中也发现有类似的情况．Ｈｐ感染组与未感染组,ｐ５３ｍＲＮＡ表达率之间统计学检验Ｐ＜００５．结论在胃癌及其癌前病变中,随着病变的发展,ｐ５３ｍＲＮＡ的表达率随之下降,Ｈｐ对其表达有明显的影响     

Helicobacter pylori infection and expression of the angiogenic factor platelet-derived endothelial cell growth factor by pre-neoplastic gastric mucosal lesions and gastric carcinoma

BACKGROUND: Expression of the angiogenic factor platelet-derived endothelial cell growth factor is induced in some gastric carcinomas. Whether angiogenesis is induced early in the development of gastric pre-neoplastic lesions and whether Helicobacter pylori infection affects platelet-derived endothelial cell growth factor expression is not known. AIM: To assess whether chronic gastritis, intestinal metaplasia, gastric dysplasia and gastric carcinomas express platelet-derived endothelial cell growth factor and whether Helicobacter pylori infection might affect the expression of platelet-derived endothelial cell growth factor in these lesions. PATIENTS AND METHODS: Patients with gastric carcinomas, atrophic gastritis with associated intestinal metaplasia, dysplasia and controls without infection or carcinoma were studied. RESULTS: Platelet-derived endothelial cell growth factor was detected by immunohistochemistry in 9 out 19 gastric carcinomas (45%). Only focal immunostaining was detected in intestinal metaplasia adjacent to dysplasia and in dysplastic cells. Of the tumours, 90% contained platelet-derived endothelial cell growth factor-positive interstitial cells. A significant correlation was found between active Helicobacter pylori infection and a larger number of platelet-derived endothelial cell growth factor-positive interstitial cells in areas of intestinal metaplasia (p<0.05). CCONCLUSION:Helicobacter pylori infection does not influence the expression of platelet-derived endothelial cell growth factor, once gastric cancer has developed. However, Helicobacter pylori infection may increase the extension of expression of platelet-derived endothelial cell growth factor by infiltrating interstitial cells in premalignant lesions, such as intestinal metaplasia, which may help create a favourable environment for tumour development. This may possibly be due to non-specific increase in recruitment of inflammatory cells caused by Helicobacter pylori infection. Further studies, with a larger number of samples, are now needed in order to confirm this finding.     

Bax and Bcl-2 protein expression in gastric precancerous lesions: immunohistochemical study

BACKGROUND AND AIMS: Bcl-2 protein prolongs cell survival in the face of classical apoptotic stimuli, and is considered to be a suppressor of apoptosis. Bax plays a key role in apoptosis by accelerating cell death after an apoptotic stimulus. The aim of our study was to determine the roles of the Bax proapoptotic gene and the Bcl-2 antiapoptotic gene in the carcinogenesis of gastric cancer. METHODS: One hundred and forty-five gastric biopsy specimens of chronic gastritis, atrophic gastritis, intestinal metaplasia and gastric dysplasia were studied. Using immunohistochemical methods, Bax and Bcl-2 protein expression was observed. RESULTS: Bax was expressed in epithelial cells in all cases of chronic gastritis. Bax was not detected in 26% of specimens of atrophic gastritis. As intestinal metaplasia develops, Bax is further suppressed. In biopsy samples with dysplasia, Bax expression was demonstrated only in 12% of biopsy samples. Although Bcl-2 protein was not detected in chronic gastritis, aberrant expression was found in gastric epithelial intestinal metaplasia and dysplasia. CONCLUSIONS: The suppression of Bax and overexpression of Bcl-2 protein is an early event in gastric tumorigenesis, before gastric dysplastic changes occur.     

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     

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     

Precancerous conditions in gastric cancer (II): relationship between atrophic gastritis-intestinal metaplasia-gastric dysplasia-gastric carcinoma

We studied a group of gastric precancerous lesions in order to analyze their mutual relationship as well as and their association with the development of gastric carcinoma of the intestinal type. This study was performed on 850 gastric biopsy specimens. Our results demonstrate the strong association of atrophic gastritis, intestinal metaplasia and gastric dysplasia (p less than 0.001) which should be considered as precursor lesions of gastric cancer. Moreover, the relations between these lesions and the intestinal type of gastric carcinoma suggest their active participation in the genesis of this type of malignancy. Our results also suggest that chronic atrophic gastritis and intestinal metaplasia evolve to the dysplasia stage before developing gastric cancer.     

Gene expression profiling using oligonucleotide microarray in atrophic gastritis and intestinal metaplasia]

BACKGROUND/AIMS: The atrophic gastritis with intestinal metaplasia of gastric mucosa has been considered to be the major factor of carcinogenesis in the stomach. However, the key molecules are still poorly understood. To elucidate the molecular genetic basis, we report the results of our initial microarray data to analyze the genome pattern in patients with atrophic gastritis and intestinal metaplasia of the stomach. METHODS: We used oligonucleotide microarray technique to evaluate the gene expression profiles in atrophic gastritis with intestinal metaplasia, in comparison with those of normal mucosa. For the identification of differentially expressed genes, Significance Analysis of Microarrays (SAM) package method was used. The results were analyzed using global normalization, intensity dependent normalization, and box plot normalization. RESULTS: Eight genes including FABP, REG, OR6C1, MEP1, SLC6A1, SI, Mucin 1, and RAB23 in mucosa of atrophic gastritis and intestinal metaplasia were up-regulated by more than 10 times as compared with normal gastric mucosa. Only one gene, LOC44119 was down-regulated by more than 10 times of the expression as compared with normal gastric mucosa. In respect to the expression of known genes related to gastric carcinogenesis, 8 genes including FN1, SRMS, TP53, TP53IMP2, TP53I3, FGFR4, TGFB1, and TGFA showed up- and down-regulations more than 2 folds in expression pattern. CONCLUSIONS: We could identify a total genome pattern in patient with atrophic gastritis and intestinal metaplasia using oligonucleotide microarray. We believe that the current results will serve as a fundamental bioinformative basis for clinical applications in diagnosis and treatment of gastric cancer and precancerous lesion in the future.     

Genetics and environmental factors in gastric carcinogenesis

BACKGROUND: Gastric cancer is considered to be the second most common cancer worldwide. Carcinogenesis of the stomach is a multi-stage process. The progression from normal epithelial to tumor cells may involve at least five stages: superficial gastritis, chronic atrophic gastritis, intestinal metaplasia, dysplasia and carcinoma. These sequential changes in the gastric mucosa may occur over a period of many years as a result of exposure to a variety of exogenous and/or endogenous factors which cause genetic alterations. Recent developments in molecular genetics have shown that the accumulation of these multiple genetic alterations, including activation of oncogenes and inactivation of tumor-suppressor genes, results in cancer development. Genetic alterations previously reported in gastric carcinomas include amplifications or mutations of the c-ERBB2, K-RAS, c-MET and TP53. Chromosomal gains were also found in various combinations with chromosomal losses and may be associated with the overexpression of dominant oncogenes contributing to tumor progression. CONCLUSIONS: These accumulated genetic changes in carcinomas provide evidences for the stepwise mode of gastric carcinogenesis through the accumulation of a series of genetic alterations.     

Global DNA hypomethylation occurs in the early stages of intestinal type gastric carcinoma.

BACKGROUND: Global DNA hypomethylation has been found in the premalignant stages of some neoplasms and has been implicated as an important factor for tumour progression. AIMS: The aim of this study was to evaluate whether DNA hypomethylation occurs during the process of gastric carcinogenesis. METHODS: Gastric specimens were obtained from 49 patients and histologically classified as: normal 10, superficial gastritis 14, chronic atrophic gastritis with intestinal metaplasia 15, and intestinal type of gastric carcinoma 10. Global DNA methylation was assessed by incubating DNA with (3H)-S-adenosylmethionine and Sss1 methylase. A higher incorporation of (3H) methyl groups reflects a lower degree of intrinsic methylation. RESULTS: A graduated increase in (3H) methyl group incorporation into DNA was found over the range extending from normal gastric mucosa, to superficial gastritis and to chronic atrophic gastritis (136,556 (24,085) v 235,725 (38,636) v 400,998 (26,747 dpm/micrograms/DNA respectively; p = 0.0002). No further increase was found in specimens from patients with carcinoma. No differences were found between extent of DNA methylation in neoplastic or non-neoplastic mucosa from patients with gastric carcinoma. Hypomethylation of DNA increased substantially with severe atrophy (p = 0.01) or with type III intestinal metaplasia (p = 0.15). CONCLUSIONS: Global DNA hypomethylation occurs in the early stages of gastric carcinogenesis, and it may be a novel biomarker of gastric neoplasia, useful in monitoring the response to chemopreventive agents.     

Effect of Helicobacter pylori infection on p53 expression of gastric mucosa and adenocarcinoma with microsatellite instability

AIM: To investigate the relationship between Helicobacter pylori (H pylori) infection, microsatellite instability and the expressions of the p53 in gastritis, intestinal metaplasia and gastric adenocarcinoma and to elucidate the mechanism of gastric carcinogenesis relating to H pylori infection. METHODS: One hundred and eight endoscopic biopsies and gastric adenocarcinoma were available for the study including 33 cases of normal, 45 cases of gastritis, 30 cases of intestinal metaplasia, and 46 cases of gastric adenocarcinoma. Peripheral blood samples of these patients were also collected. H pylori infection and p53 expressions were detected by means of streptavidin-peroxidase (SP) immunohistochemical method. Microsatellite loci were studied by PCR-SSCP-CE using the markers BAT-26, D17S261, D3S1283, D2S123, and D3S1611. MSI was defined as the peak shift in the DNA of the gastric tissue compared with that of the peripheral blood samples. Based on the number of mutated MSI markers, specimens were charac-terized as high MSI (MSI-H) if they manifested instability at two or more markers, low MSI (MSI-L) if unstable at only one marker, and microsatellite stable (MSS) if they showed no instability at any marker. RESULTS: H pylori infection was detected in the samples of gastritis, intestinal metaplasia, and gastric adenocarcinoma and the infection frequencies were 84.4%, 76.7%, and 65.2%, respectively, whereas no H pylori infection was detected in the samples of normal control. There was a significant difference in the infection rates between gastritis and carcinoma samples (P= 0.035). No MSI was detected in gastritis samples, one MSI-H and two MSI-L were detected among the 30 intestinal metaplasia samples, and 12 MSI-H and 3 MSI-L were detected in the 46 gastric carcinomas. In those gastric carcinomas, the MSI-H frequency in H pylori-positive group was significantly higher than that in H pylori- negative group. No p53 expression was detected in the normal and gastritis samples from dyspeptic patients. P53-positive immunohistochemical staining was detected in 13.3% of intestinal metaplasia samples and in 43.5% of gastric carcinoma samples. The levels of p53 in H pylori-positive samples were higher than those in the negative group when the carcinoma samples were subdivided into H py/ori-positive and -negative groups (P=0.013). Eight samples were detected with positive p53 expression out of the 11 MSI-H carcinomas with H pylori infection and no p53 expression could be seen in the H pylori-negative samples. CONCLUSION: H pylori affect the p53 pattern in gastric mucosa when MMR system fails to work. Mutations of the p53 gene seem to be an early event in gastric carcinogenesis.     

Immunohistochemical expression of cell-cycle proteins in gastric precancerous lesions

Background: The early indicator for the subject predisposed to gastric cancer is abnormal proliferation of gastric epithelial cells, such as atrophic gastritis (AG), intestinal metaplasia (IM), and dysplasia, which have been considered as precancerous lesions of gastric cancer. To determine whether p53 protein, cyclins D1, and D3, and p27^kip1 play a role in the carcinogenesis pathway of gastric cancer, we performed an immunohistochemical study of their expression in gastric precancerous lesions. Methods: A total of 1 45 endoscopic gastric biopsy specimens of AG, IM, and gastric dysplasia were studied. These molecular markers were localized by immunohistochemistry. Results: P53 was expressed in 15% of cases with gastric dysplasia and not in the pre‐dysplastic stages of the gastric mucosa. All cases were concerning high‐grade dysplasia. Cyclin D1 protein was almost undetectable in the precancerous lesions of gastric cancer. Cyclin D3 protein overexpression was seen in 10% of biopsies with IM, and 50% of biopsies with gastric dysplasia. High expression of p27^kip1 protein was demonstrated in all cases of chronic gastritis. As atrophy, IM, and dysplasia develop, expression of p27^kip1 protein is suppressed. In total, 15% of dysplastic cases showed no expression of p27^kip1 protein. Conclusions: (i) P53 mutation must be a late event during the development of gastric cancer. (ii) Cyclin D1 protein overexpression may not play a role in the progression from normal to neoplastic gastric mucosa, while overexpression of cyclin D3 is an earlier event during gastric carcinogenesis, and its role must be further evaluated. (iii) Reduced expression of p27^kip1 is a rather early event in gastric tumorigenesis, before dysplastic changes occur.     

Prevalence of Helicobacter pylori infection and gastric cancer precursor lesions in patients with dyspepsia

BACKGROUND: Helicobacter pylori infection has been considered to play significant role in gastric carcinogenesis, but only a minority of people who harbor this organism will develop gastric cancer. H. pylori infection first causes chronic non atrophic gastritis. Chronic non atrophic gastritis may evolve to atrophic gastritis and intestinal metaplasia and finally to dysplasia and adenocarcinoma. AIMS: To estimate the prevalence of H. pylori infection and the precancerous gastric lesions and their relationship, in patients with dyspeptic symptoms who underwent upper gastrointestinal endoscopy at a reference center in the central region of Rio Grande do Sul state, Brazil. METHODS: We analyzed gastric biopsies taken from corpus and antrum of patients who underwent upper gastrointestinal endoscopy for H. pylori detection, between 1994 and 2003. According to Sydney system, chronic non atrophic gastritis, atrophic gastritis and intestinal metaplasia were diagnosed by histological examination (H-E stain). The histological diagnoses were related to H. pylori infection status. RESULTS: Biopsies from 2,019 patients were included in the study. Patients mean age was 52 (+/-15) and 59% were female. Seventy six percent had H. pylori infection. Normal mucosa, chronic non atrophic gastritis, atrophic gastritis and intestinal metaplasia were diagnosed in 5%, 77%, 3% and 15%, respectively. The OR for any degree of gastric mucosa lesion in infected patients was 10 (CI95% 6.50 - 17%). The OR for infected patients had chronic non atrophic gastritis was 3 (CI95% 2,2 - 3,4). The OR for infected patients had atrophic gastritis or intestinal metaplasia was less than 1. CONCLUSIONS: The prevalence of H. pylori infection in this population was high (76%) and infected individuals had the probability 10 folds greater than non infected individuals to have any lesion of gastric mucosa. The prevalence of precancerous lesions was 77% for non atrophic chronic gastritis, 3% for atrophic gastritis and 15% for intestinal metaplasia. Infected patients had risk 3 folds greater than non-infected for the occurrence of non atrophic chronic gastritis. H. pylori infection did not show risk for occurrence of atrophic gastritis and intestinal metaplasia, suggesting that other risk factors should be involved in the carcinogenesis process.     

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.     

胃黏膜癌前病变中p53、p21^ras蛋白表达与幽门螺杆菌感染的关系

目的观察幽门螺杆菌(Helicobacterpylori)感染及根除H.pylori二年后p53、p21ras在二组胃黏膜上皮细胞的表达,探讨H.pylori在胃癌发生、发展中的作用.方法应用免疫组织化学染色、尿素酶快速试验(RUT)、组织学Warthin-Starry染色.198例H.pylori感染患者,慢性胃炎86例,慢性胃炎伴肠化生67例,慢性胃炎伴异型增生45例;对照组为根除H.pylori 2年后共86例,其中慢性胃炎54例,慢性胃炎伴肠化生32例,慢性胃炎伴异型增生10例.全部病例做p53、p21ras免疫组织化学染色.结果 H.pylori感染组p53、p21 ras 阳性表达率15.7%、18.7%,明显高于H.pylori根除组2.3%、7%,差异显著(P＜0.05);慢性胃炎伴肠化病变中,p53、p21ras在H.pylori感染组阳性表达率17.9%、18.4%均高于H.pylori根除组0%、9.4%,差异显著(P＜0.05)慢性胃炎伴异型增生病变中,p53、p21 ras在H.pylori感染组阳性表达率31.1%、40%均高于H.pylori根除组20%、30.4%,差异显著(P＜0.05);H.pylori 感染组p53、p21ras在慢性胃炎,肠化生,异型增生表达水平依次增高p53、p21ras共同表达阳性37例.结论在胃黏膜癌前病变中p53、p21ras 在H.pylori感染组阳性表达率高于H.pylori根除组,差异显著(P＜0.05);在慢性胃炎,肠化生,异型增生p53、p21ras表达水平在增高;p53、p21 ras表达呈正相关;H.pylori感染在胃癌发生、发展过程中起一定作用,p53、p21ras表达可能是H.pylori致癌的作用机理之一.     

胃癌及癌前病变组织三叶因子3表达的相关性研究

目的检测三叶因子3（TFF3）在胃癌前病变及胃癌的表达,探讨TFF3的表达与胃癌发生、发展的关系。方法收集慢性浅表性胃炎（CSG）,慢性萎缩性胃炎伴中、重度肠上皮化生（IM）,慢性萎缩性胃炎伴中重度不典型增生（Dys）患者各30例,胃癌（GC）患者40例采用SP免疫组化法检测TFF3蛋白的表达。结果CSG、IM、Dys、GC组织中TFF3表达呈逐渐增强趋势,差异具有统计学意义（P〈0.05）。结论TFF3表达在胃癌发生、发展过程中起一定作用。     

胃粘膜癌变过程中幽门螺杆菌感染与p53,c-erbB-2基因表达的研究

目的探讨胃粘膜癌变过程中幽门螺杆菌（Ｈｅｌｉｃｏｂａｃｔｅｒｐｙｌｏｒｉ,Ｈｐ）感染与ｐ５３,ｃｅｒｂＢ２基因表达的关系．方法浅表性胃炎１６例,肠上皮化生２２例,异型增生１４例,早期胃癌１８例及进展期胃癌４０例作为研究对象．用ＷａｒｔｈｉｎＳｔａｒｙ银染色法检测Ｈｐ,用免疫组化Ｓｐ法检测ｐ５３和ｃｅｒｂＢ２的基因表达产物．结果Ｈｐ,ｐ５３,ｃｅｒｂＢ２在浅表性胃炎的检出率各为５００％,００％,００％;在肠上皮化生的检出率各为５９１％,２２７％,１３６％;在异型增生的检出率各为８５７％,６４３％,２８６％;在早期胃癌的检出率各为１６７％,３３３％,１１１％;在进展期胃癌的检出率各为５０％,５２５％,５５０％;在癌旁粘膜的Ｈｐ检出率为８６７％;在癌前病变中,Ｈｐ阳性组的ｐ５３,ｃｅｒｂＢ２表达率均高于Ｈｐ阴性组．结论Ｈｐ感染参与了胃癌前病变的发生与发展;Ｈｐ感染可引起野生型ｐ５３基因失活和ｃｅｒｂＢ２基因激活,从而导致胃粘膜的癌变．     

胃癌及癌前病变中P57~(KIP2)和PCNA的表达

探讨P57KIP2和PCNA在胃癌及癌前病变中的表达及意义。方法采用免疫组织化学技术SP法,检测P57KIP2和PCNA在57例胃癌(GC)、7例不典型性增生(Dys)、16例肠上皮化生(IM)、15例慢性萎缩性胃炎(CAG)及10例慢性浅表性胃炎(CSG)中的表达情况,并分析与胃癌临床病理之间的关系。结果P57KIP2在GC、Dys、IM、CAG、CSG中阳性表达率分别为43.9%、57.1%、81.3%、80.0%、80.0%,GC和Dys组的P57KIP2阳性表达率明显低于IM、CAG、CSG组(P均0.05);PCNA在GC、Dys、IM、CAG、CSG组阳性表达率分别为80.7%、85.7%、75.0%、46.7%、30.0%,GC、Dys、IM组PCNA表达率明显高于CAG、CSG组(P0.05);P57KIP2和PCNA均与胃癌组织分化程度相关(P0.05),而与淋巴结转移、浸润、临床分期无显著相关性(P0.05)。结论在胃黏膜癌变过程中,P57KIP2蛋白的失活不是一个早期基因事件,随着病变进展PCNA表达逐渐增加,P57KIP2蛋白表达下降和PCNA的表达增高可能在胃癌的发生发展中起重要作用,两者共同检测有助于胃癌恶性程度的判定。     

Mitochondrial microsatellite instability in gastric cancer and its precancerous lesions

AIM: To evaluate the role of mitochondrial microsatellite instability (mtMSI) in gastric carcinogenesis. METHODS: MtMSI was measured with PCR-single strand conformation polymorphism (PCR-SSCP) in 68 cases of advanced gastric cancer, 40 cases of chronic gastritis, 30 cases of intestinal metaplasia and 20 cases of dysplasia. RESULTS: MtMSI was observed in 12.5% (5 of 40) of chronic gastritis, 20.0% (6 of 30) of intestinal metaplasia, 25.0% (5 of 20) of dysplasia and 38.2% (26 of 68) of gastric cancer. These findings showed a sequential accumulation of mtMSI in the histological progression from chronic gastritis to gastric cancer. An association of mtMSI with intestinal histological type and distal location was found (P=0.001 and P=0.002), whereas no significant correlation was found between mtMSI and age at diagnosis, sex, tumor size, depth of invasion, lymph node spread and clinical stages (P>0.05). CONCLUSION: MtMSI may play an early and important role in the gastric carcinogenesis pathway, especially in the intestinal type and distal gastric cancer.     

Expression of polycomb protein EZH2 in multi-stage tissues of gastric carcinogenesis

OBJECTIVE: To study the role and significance of the polycomb group (PcG) protein EZH2 (enhancer of zeste homolog 2) in the multi-step process of intestinal-type gastric carcinogenesis. METHODS: Gastric specimens were obtained from 142 patients with gastric disease, including 34 with chronic non-atrophic gastritis (NCAG), 33 chronic atrophic gastritis (CAG) with intestinal metaplasia (IM), 40 CAG with dysplasia (DYS) and 35 with intestinal-type gastric carcinomas (GC), and 32 Helicobacter pylori-negative controls. The EZH2 protein was stained by the immunohistochemical method and was expressed as the intensity and percentage of the total number of epithelial cells. The chronic gastritis and the grading of dysplasia were classified according to Chinese National Consensus on chronic gastritis and the Padova international classification. RESULTS: The EZH2 protein levels in the specimens of normal gastric tissue, NCAG, CAG with IM, DYS and intestinal-type GC were gradually increased (P < 0.05), but statistical significance was not found between the groups of DYS and GC. CONCLUSION: PcG protein EZH2 plays an important role in the multi-step process of intestinal-type gastric carcinogenesis.