Studies on microsatellite instability in p16 gene and expression of hMSH2 mRNA in human gastric cancer tissues

AIM: To detect the loss of heterozygosity (LOH) frequency of microsatellite sites D9s171, D9s1604 of p16 gene and expression of hMSH2 mRNA in various differentiated types of gastric cancer, adjacent cancer tissues and normal gastric mucosa. METHODS: LOH was detected by polymerase chain reaction (PCR)-denaturing polyacrylamide gel electrophoresis-silver staining. The expression of hMSH2 mRNA was examined with in situ hybridization. RESULTS: The frequency rate of LOH was significantly higher in gastric cancers than that in adjacent cancer tissues (P=0.032). No significant difference was noted among various differentiated types and various clinical stages of gastric cancers. The significantly reduced expression of hMSH2 mRNA positive signal cells exhibited in gastric cancers, in comparison with that in the adjacent cancer tissues and normal gastric mucosa, respectively (P=0.001). No significant difference was noted among various clinical stages of gastric cancers (P>0.05). The difference of positive signal cells in poorly differentiated cancers and those in well and moderately differentiated cancers were significant (P<0.001). CONCLUSION: The frequencies of LOH in two microsatellite sites, D9s171 and D9s1604, in p16 genome were associated with development of gastric cancer and no significant correlation was demonstrated between the LOH frequency and the cell differentiated types of tumor cells or clinical stages. There was a positive relationship between the expression of hMSH2 mRNA and the differentiated types of gastric cancer.     

Significance and relationship between Yes-associated protein and survivin expression in gastric carcinoma and precancerous lesions

AIM： To analyze the differences and relevance of Yesassociated protein （YAP） and survivin, and to explore the correlation and significance of their expression in gastric carcinoma and precancerous lesions.
METHODS： The PV9000 immunohistochemical method was used to detect the expression of YAP and survivin in 98 cases of normal gastric mucosa, 58 intestinal metaplasia （IM）, 32 dysplasia and 98 gastric carcinoma.
RESULTS： The positive rates of YAP in dysplasia （37.5%） and gastric carcinoma （48.0%） were significantly higher than that in normal gastric mucosa （13.3%）, P 〈 0.01. The positive rates of survivin in IM （53.4%）, dysplasia （59.4%） and gastric carcinoma （65.3%） were significantly higher than in normal gastric mucosa （11.2%）, P 〈 0.01. Survivin expression gradually increased from 41.7% in well differentiated adenocarcinoma through 58.3% in moderately differentiated adenocarcinoma to 75.6% in poorly differentiated adenocarcinoma, with significant Rank correlation, rk = 0.279, P 〈 0.01. The positive rate of survivin in gastric carcinoma of diffused type （74.6%） was significantly higher than that in intestinal type （51.3%）, P 〈 0.05. In gastric carcinoma with lymph node metastasis （76.9%）, the positive rate of survivin was significantly higher than that in the group without lymph node metastasis （41.2%）, P 〈 0.01. In 98 cases of gastric carcinoma, the expression of YAP and of survivin were positively correlated, rk = 0.246, P 〈 0.01.
CONCLUSION： YAP may play an important role as a carcinogenic factor and may induce survivin expression. Detecting both markers together may help in early diagnosis of gastric carcinoma.     

Significance of vascular endothelial growth factor messenger RNA expression in gastric cancer

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MTA1基因表达与人胃癌的浸润和转移

目的:探讨MTA1基因在胃癌及癌周组织中的表达及其表达水平与胃癌浸润和转移潜能的相关性.方法:采用荧光定量PCR及Western印迹技术,分别在mRNA和蛋白水平检测42例手术切除的人胃癌组织及癌旁组织中MTA1的表达,结合胃癌的临床生物学特征分析MTA1表达与胃癌病理类型、淋巴结转移的关系.结果:胃癌组织中MTA1mRNA相对量的表达显著高于癌旁胃黏膜组织(0.6711vs0.3940,P<0.01),蛋白水平表达与mRNA一致.低分化胃腺癌组织中的MTA1mRNA的相对量表达显著高于中高分化胃腺癌组织(0.7475vs0.3460,P<0.01),而伴有淋巴结转移的胃癌组织中MTA1mRNA的相对量表达明显高于不伴有淋巴结转移的胃癌组织(0.8128vs0.4933,P<0.01).结论:MTA1的表达与促进胃癌的转移相关,检测MTA1表达可作为预测胃癌生物学行为、判断胃癌患者预后的一个参考指标.     

Endocrine cells in extrahepatic bile duct carcinoma

Summary A total of 44 extrahepatic bile duct carcinomas comprising 13 well-differentiated adenocarcinomas, 25 moderately differentiated adenocarcinomas, and 6 poorly differentiated adenocarcinomas were examined histologically and immunohistochemically for somatostatin, gastrin, and glicentin. Argyrophil cells, argentaffin cells, and somatostatin- and gastrin-immunoreactive cells within the tumor were detected in 46.2%, 15.4%, 23.1%, and 15.4% of well-differentiated adenocarcinomas, and in 16.0%, 8.0%, 12.0%, and 4.0% of moderately differentiated adenocarcinomas, respectively. No tumor tissues of poorly differentiated adenocarcinomas contained endocrine cells. A statistically significant difference in the frequency of argyrophil cells was observed between well and poorly differentiated adenocarcinoma. The incidence of argyrophil cells and somatostatin-immunoreactive cells in nonneoplastic mucosa adjacent to well-differentiated adenocarcinoma was higher than in that adjacent to poorly differentiated adenocarcinoma. Glicentin-immunoreactive cells could not be demonstrated either in tumor tissue or in nonneoplastic mucosa of the extrahepatic bile duct. With reference to the histogenesis of extrahepatic bile duct carcinoma, it was assumed from these results that the development of well-differentiated adenocarcinoma might be closely related to the occurrence of endocrine cells and that poorly differentiated adenocarcinoma might develop from ordinary mucosa.     

An experimental study on the fibrosis of scirrhous gastric carcinoma

9 surgical specimens of gastric carcinoma were examined for their immunoreactivity with type I procollagen antiserum. For specimens of the four Borrmann type IV carcinomas and one of Borrmann type III carcinomas, all of which exhibited abundant fibrous stroma (histologically scirrhous), the cytoplasm of the tumor cells was strongly positive. In contrast, the tumor cells of the non-scirrhous carcinoma (histologically medullary) were poorly reactive to type I procollagen antiserum. We found the cells, which were established from scirrhous carcinoma (KATO III), express type I procollagen mRNA (4.8 kb, 6.0 kb) as revealed by dot blot analysis and Northern blot hybridization. And we determined the presence of type I procollagen related antigen in the cell culture medium of KATO III using RIA and Western blotting. Administration of glucocorticoid to KATO III caused decrease of procollagen mRNA expression. It was revealed that collagen synthesis of scirrhous gastric carcinoma was regulated by glucocorticoid in the same manner of fibroblast.     

利用组织芯片技术研究PTEN和VEGF在胃癌中的表达及意义

目的研究PTEN和血管内皮生长因子（vascular endothelial growth factor，VEGF）在胃癌中的表达及临床意义。方法应用组织微阵列仪制作97孔胃癌组织芯片（tissue microarray）。用免疫组织化学S—P法检测PTEN、VEGF在72例胃癌和25例正常胃黏膜中的表达。结果胃癌组织中PTEN蛋白阳性表达率显著低于正常胃黏膜（45．8％ VS 100％，P〈0．01）；VEGF的阳性表达率显著高于正常胃黏膜（75％VSl2％，P〈0．01），PTEN在胃癌中的表达与VEGF呈负相关（P〈0．01）。PTEN、VEGF的表达在中高分化腺癌分别为68．8％、62．5％（P〉0．05），在低分化及未分化腺癌分别为27．5％、85．0％（P〈0．05）；伴淋巴结转移者分别为31．6％、86．9％（P〈0．05），无淋巴结转移者分别为61．8％、61。8％（P〉0．05）；临床病理分期Ⅰ＋Ⅱ期分别为57．1％、61．9％（P〉0．05），Ⅲ＋Ⅳ期分别为30．0％、93．3％（P〈0．05）；与性别、年龄、肿瘤大小和组织分型无显著差异（P〉0．05）。结论PTEN失活或蛋白表达降低、VEGF的高表达与胃癌临床病理特征和生物学行为有密切关系。PTEN在低分化或未分化以及伴淋巴结转移和临床Ⅲ＋Ⅳ期胃癌中的表达与VEGF呈负相关。联合检测PTEN、VEGF对胃癌的恶性程度及预后判断具有一定的临床参考意义。应用组织芯片大规模高效检测临床组织样本是可行的，具有快速、准确、方便经济的特点。     

Expression of nitric oxide synthase in human gastric carcinoma and its relation to p53, PCNA

AIM: To investigate the expression of NOS in gastric carcinoma, and to explore the relationship between the expression of nitric oxide synthases (NOS) and p53, PCNA, pathological features and clinical staging of gastric cancer. METHODS: The activity of NOS protein was investigated in 85 samples of human gastric carcinoma and 25 samples of normal gastric mucosal tissue by biochemical assay. We then examined the expression of NOS, p53, PCNA in 85 samples of human gastric cancer was examined by immunohistochemistry, and NOS mRNA expression in 85 gastric cancer tissue specimens by In situ hybridization. RESULTS: Biochemical assay showed that the activity of NOS was significantly higher in gastric carcinoma than in normal gastric mucosal tissues (t=0.4161, P＜0.01). Immunohistochemistry revealed that endothelial nitric oxide synthase (eNOS) expressed in all samples of normal gastric mucosa, but only 6 cases of 85 gastric cancer specimens showed weak positive immunohistochemical reactions to eNOS (20%). Inducible nitric oxide synthase (iNOS) was expressed strongly in human gastric carcinoma (81.2%). In situ hybridization analysis showed that iNOS mRNA expression was significantly stronger than eNOS mRNA expression in gastric cancer tissue (X~2 = 10.23, P＜0.01). The expression of iNOS in gastric cancer was associated with differentiation, clinical stages or lymph node metastases (r=0.3426,P＜0.05). However, iNOS expression did not correlate with histological classifications and morphological types. The expression of iNOS was significantly correlated with p53 or PCNA expression (r=0.3612, P＜0.05). The expression of neuronal nitric oxide synthase (nNOS) was not examined by immunohistochemistry and in situ hybridization in gastric cancer specimens and normal gastric mucosa. CONCLUSION: In human gastric cancer, there is an enhanced expression of iNOS, but not of eNOS. NOS promotes the proliferation of tumor cells and plays an important role in gastric cancer spread. Inactivation of antioncogene p53 and overexpression of iNOS might play a synergetic role in the process of carcinogenesis of human gastric carcinoma.     

Gastric carcinoma: monoclonal epithelial malignant cells expressing Epstein-Barr virus latent infection protein.

In 1000 primary gastric carcinomas, 70 (7.0%) contained Epstein-Barr virus (EBV) genomic sequences detected by PCR and Southern blots. The positive tumors comprised 8 of 9 (89%) undifferentiated lymphoepithelioma-like carcinomas, 27 of 476 (5.7%) poorly differentiated adenocarcinomas, and 35 of 515 (6.8%) moderately to well-differentiated adenocarcinomas. In situ EBV-encoded small RNA 1 hybridization and hematoxylin/eosin staining in adjacent sections showed that the EBV was present in every carcinoma cell but was not significantly present in lymphoid stroma and in normal mucosa. Two-color immunofluorescence and hematoxylin/eosin staining in parallel sections revealed that every keratin-positive epithelial malignant cell expressed EBV-determined nuclear antigen 1 (EBNA1) but did not significantly express CD45+ infiltrating leukocytes. A single fused terminal fragment was detected in each of the EBNA1-expressing tumors, thereby suggesting that the EBV-carrying gastric carcinomas represent clonal proliferation of cells infected with EBV. The carcinoma cells had exclusively EBNA1 but not EBNA2, -3A, -3B, and -3C; leader protein; and latent membrane protein 1 because of methylation. The patients with EBV-carrying gastric carcinoma had elevated serum EBV-specific antibodies. The EBV-specific cellular immunity was not significantly reduced; however, the cytotoxic T-cell target antigens were not expressed. These findings strongly suggest a causal relation between a significant proportion of gastric carcinoma and EBV, and the virus-carrying carcinoma cells may evade immune surveillance.     

Tissue isoantigens A,B and H in primary carcinoma of the pancreas

AIM: To investigate the quantity of demonstrable tissue isoantigens A, B and H in primary carcinoma of the pancreas and their relationship with the degree of anaplasia. METHODS: The pathological classification of 26 primary carcinomas of the pancreas and their anaplasia were studied by light microscopy with HE staining. The quantity of isoantigens A, B and H in carcinomas of the pancreas and their adjacent normal pancreas tissues were studied by immunohistochemical method. RESULTS: Twenty-six primary carcinomas of the pancreas were classified as follows: Two acinar cell carcinomas, 22 adenocarcinoma, 1 adenocanthoma and 1 undifferentiated carcinoma. One of 2 acinar cell carcinomas, 6 of 22 adenocarinomas and 1 adenocanthoma were well differentiated; 1 of 2 acinar carcinomas and 12 of 22 adenocarcinoma were moderately differentiated; 4 of 22 adenocarcinoma and 1 undifferentiated carcinoma were poorly differentiated. The results of the immunohistochemical method showed that the ABH positive cells were more frequent in acinar cells and ductal epithelial cells in the adjacent normal pancreas than those in carcinoma of the pancreas. In 22 adenocarcinoma, the ABH positive cells were more frequent in well differentiated and moderately differentiated cancer cells than in poorly differentiated cells. In 11 invasive adenocarcinoma positive cells (++ or +++) were more frequent in primary foci than in metastatic foci. Twenty of 26 carcinomas of the pancreas belonged to A, B and AB blood groups. Most H isoantigens were converted to A or B or AB substances in 8 well differentiated, 7 moderately differentiated and 2 poorly differentiated carcinomas, while less transformation of H to A or B antigen was observed in 3 poorly differentiated carcinomas of the pancreas. Furthermore, it was observed that the secretion of isoantigens A, B, and H was less in carcinomas of the pancreas than in normal pancreas. CONCLUSION: The loss of demonstrable isoantigens ABH parallels morphological anaplasia. Furthermore, we found that the functions of transformation of H substance into A and B substances as well as the secretion of ABH substances into the pancreatic duct were hampered.     

p62 Expression in primary carcinomas of the digestive system

AIM: To characterize p62 expression and define the relationship between p62 expression and cell proliferation in primary carcinomas of the digestive system. METHODS: p62 expression was characterized in surgically resected tumor specimens from 60 patients with primary carcinomas of the digestive tract (including 22 esophageal carcinomas, 17 gastric carcinomas, and 21 colorectal carcinomas) and 40 patients with hepatocellular carcinoma (HCC) by immunohistochemistry (IHC). The cell proliferation was determined by IHC of Ki-67 in 40 patients with HCC. RESULTS: Twenty-two cases of esophageal carcinoma were histopathologically diagnosed as squamous cell carcinoma. We combined the gastric and colorectal carcinomas based on the equivalent histology. The 38 tumors in the combined groups, consisted of 17 well-differentiated, eight moderately differentiated, nine poorly differentiated carcinomas, and four mucinous adenocarcinomas. According to the criteria of Edmondson and Steiner, 40 patients with HCC were graded (2 grade Ⅰ,17 grade Ⅱ and 21 grade Ⅲ). p62 expression in primary carcinomas of the gastrointestinal tract (60/60,100%) was higher than that (27/40, 67.5%) of HCC (P<0.01, %2 = 19.63). High expression levels of p62 were positively correlated with histological grades in gastric and colorectal carcinomas (P<0.0001) and inversely associated with those in HCC (P = 0.0322). No significant correlations were observed for esophageal carcinomas (P = 0.8246). p62 expression was also detected in the cytoplasm of morphologically normal columnar epithelial cells adjacent to the cancer foci of gastric and colorectal carcinomas. In 40 HCC specimens, the mean Ki-67 labeling index (LI) was (19.6±16.0)%. It was (28.3±18.73)% in 12 cases with high p62 expression (+++), (7.53±14.83)% in 13 cases without p62 expression(-). Patients with a high p62 expression showed a significantly higher level of Ki-67 staining than those without p62 expression (P<0.05, t = 2,069). CONCLUSION: p62 expression is common in carcinomas of the digestive system and higher in carcinomas of the gastrointestinal tract than in primary HCC. p62 is a cellular differentiation-related protein. Cancer cells with a high p62 expression exhibited highgrowth fractions in HCC.     

Expression of ATP7B in human gastric cardiac carcinomas in comparison with distal gastric carcinomas

~~Expression of ATP7B in human gastric cardiac carcinomas in comparison with distal gastric carcinomas~~1 Wang LD, Zheng S, Zheng ZY, Casson AG. Primary adenocarcinomas of lower esophagus, esophagogastric junction and gastric cardia: in special refere…     

胃癌组织中KISS-1和MMP-9的表达及其意义

目的探讨肿瘤转移抑制基因K ISS-1及基质金属蛋白酶9（MMP-9）与胃癌侵袭、转移的关系,为研究胃癌的转移机制及治疗提供理论基础。方法采用逆转录聚合酶链反应（RT-PCR）检测36例胃癌组织及36例正常胃组织中K ISS-1 mRNA及MMP-9 mRNA的表达情况,分析其与胃癌患者各临床病理指标的关系及二者的相关性。结果 K ISS-1 mRNA在胃癌组织中的阳性表达率及表达水平均低于正常胃组织（P均〈0.01）,并且其低表达与淋巴结转移密切相关（P〈0.05）;MMP-9 mRNA在胃癌组织中的阳性表达率及表达水平均高于正常胃组织（P均〈0.05）,MMP-9 mRNA的高表达与癌的浸润深度和淋巴结转移密切相关（P均〈0.05）;K ISS-1与MMP-9表达呈负相关（P〈0.05）。结论 K ISS-1表达缺失和MMP-9过表达可能与胃癌的侵袭相关。     

Carcinoembryonic antigen detection by immunocytochemical methods in carcinomas of the colon and stomach

CEA was studied in paraffin sections from 50 cases of colonic and 50 cases of gastric adenocarcinoma using immunoperoxidase and immunofluorescence techniques. CEA was positive more frequently in colonic (86 per cent) than in stomach carcinoma (76 per cent). Immunoperoxidase was found to be the more sensitive technique for the detection of CEA in both organs. The non-neoplastic peritumoral colonic mucosa was more often CEA positive than was the peritumoral gastric mucosa. CEA was found more often, and the intensity of the staining was stronger in well-differentiated colonic and gastric carcinoma than it was in poorly differentiated carcinoma. No relation was found between the presence of CEA in colonic and gastric carcinoma and the stages of the disease. CEA was detected more frequently in carcinomas of the left colon than in carcinomas of the right colon.     

Expression of mucins and E-cadherin in gastric carcinoma and their clinical significance

AIM: To investigate the expression of three types of mucin(MUC1, MUC2, MUC5AC) and E-cadherin in human gastric carcinomas and their clinical significance. METHODS: Ninety-four gastric cancer specimens were classified according to WHO criteria and detected by immunohistochemical assay of expression of mucins and E-cadherin. RESULTS: The positive expression rates of MUC1, MUC2, MUC5AC and E-cadherin were 82% (77/94), 84% (79/94), 40% (38/94) and 56% (53/94) respectively. MUC1 expression was significantly correlated with the types of cancer (the positive rates of MUC1 in well and moderately differentiated tubular adenocardnoma, poorly differentiated adenocardnoma, signet-ring cell carcinoma and mucinous carcinoma were 91%, 87%, 71%, 71%, respectively, P&lt;0.05), age of patients (the positive rates of it among the people who are younger than 40 years, between 40-60 years and over 60 yearwere 74%, 81%, 89%, P&lt;0.05), lymph nodes involvement (the positive rates in the non-interfered group and the interfered group were 78%, 85%, P&lt;0.05) and tumor size (the positive rates in the tumors with the size less than 3 cm, 3-6 cm and larger than 6 cm were 69%, 92%, 69%, P&lt;0.05); MUC2 expression was significantly associated with types of cancers and had the strongest expression in mucinous carcinomas (the posrdve rates of MUC2 in well and moderately differentiated tubular adenocardnoma, poorly differentiated adenocardnoma,signet-ring cell carcinoma and mucinous carcinoma were 94%, 70%, 81%, 100%, P&lt;0.05), but it had no obvious relation to age, gender, tumor location, lymph nodes involvement,depth of invasion and metastasis to extra-gastric organs (P&gt;0.05); MUC5AC expression was not related to any of the characteristics investigated except that it had relation to gender, whereas MUC5AC showed the tendency to higher expression in less invasive lesions and lower expression in advanced stage cancers (P&gt;0.05); No significant difference was found for E-cadherin expression. There were strong positive relationships between the expression of MUC1 and E-cadherin, MUC2 and E-cadherin, MUC1 and MUC2(R=0.33, R=0.22, R=0.32, respectively, P&lt;0.05). According to the COX proportional hazards model, older patients, involvement of lymph nodes, different types of gastri ccancer and MUC2 expression were significantly associated with poorer outcome of gastric carcinoma patients (β=0.08,β=3.94, β=1.33, β=0.75, respectively, P&lt;0.05). CONCLUSION: MUC1 and MUC2 are good markers of different types of gastric cancer. MUC2 is especially a good marker of mucinous carcinoma. MUCl, MUC2 may interfere with the function of E-cadherin in gastric carcinomas, and have synergic effect on progression of gastric cancers.     

Significance of cyclooxygenase—2 expression in human primary hepatocellular carcinoma

AIM：To clarife the significance of cyclooxygenase-2(COX-2)expression in human primary hepatcellular carcinoma(HCC)and adjacent nontumorous tissues.METHODS;TheCOX-2protein and mRNA were investigated in 27HCC tissues with adjacent nontumorous tissues,and 5histologically normal liver tissues,using immunohistochemistry and in situ hybridization.RESULTS:The well-differentiated HCC expressed COX-2protein(5.68&#177;1.19)more strongly than moderated HCC(3.43&#177;1.98)and poor differentiated HCC(3.33&#177;1.50)(P&lt;0.05 respectively),adjacent nontumorous tissues(4.93&#177;1.05)and normal live tissues(3.20&#177;1.92)(P&lt;0.01 respectively);More intensive staining of COX-2in adjacent nontumorous tissues was observed than that in normal liver tissues(P&lt;0.05).There was no significant difference among adjacent nontumorous tissues,moderately differentiated HCC and poorly differentiated HCC(P&gt;0.05).The expression of COX-2mRNA was observed in the cytoplasm of the cells of HCC and of gtthe hepatocytes in adjacent nontumorous tissues in which COX-2 protein was positive.CONCLUSION:The overexpression of COX-2 in well-differentiated HCsuggets that COX-2 may play a role in the early stages of hepatocarcinogensis.     

Expression and significance of proapoptotic gene Bax in gastric carcinoma

ＩＮＴＲＯＤＵＣＴＩＯＮＲｅｃｅｎｔｉｎｖｅｓｔｉｇａｔｉｏｎｓｈａｖｅｄｅｍｏｎｓｔｒａｔｅｄｔｈａｔａｐｏｐｔｏｓｉｓｐｌａｙｓａｓｉｇｎｉｆｉｃａｎｔｒｏｌｅｉｎｔｈｅｐａｔｈｏｇｅｎｅｓｉｓｏｆｔｕｍｏｒｓ［１,２］．Ｅｍｐｈａｓｉｓｈａｓ...     

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.