Identification of Annexin A1 protein expression in human gastric adenocarcinoma using proteomics and tissue microarray

AIM:To study the differential expression of Annexin A1(ANXA1)protein in human gastric adenocarcinoma.This study was also designed to analyze the relationship between ANXA1 expression and the clinicopathological parameters of gastric carcinoma.METHODS:Purified gastric adenocarcinoma cells(GAC)and normal gastric epithelial cells(NGEC)were obtained from 15 patients with gastric cancer by laser capture microdissection.All of the peptide specimens were labeled as18O/16O after trypsin digestion.Differential protein expressions were quantitatively identified between GAC and NGEC by nanoliter-reverse-phase liquid chromatography-mass/mass spectrometry(nanoRPLC-MS/MS).The expressions of ANXA1 in GAC and NGEC were verified by western blot analysis.The tissue microarray containing the expressed ANXA1 in 75 pairs of gastric carcinoma and paracarcinoma specimens was detected by immunohistochemistry(IHC).The relationship between ANXA1 expression and clinicopathological parametes of gastric carcinoma was analyzed.RESULTS:A total of 78 differential proteins were identified.Western blotting revealed that ANXA1 expression was significantly upregulated in GAC(2.17/1,P<0.01).IHC results showed the correlations between ANXA1protein expression and the clinicopathological parameters,including invasive depth(T stage),lymph node metastasis(N stage),distant metastasis(M stage)and tumour-lymph node metastasis stage(P<0.01).However,the correlations between ANXA1 protein expression and the remaining clinicopathological parameters,including sex,age,histological differentiation and the size of tumour were not found(P>0.05).CONCLUSION:The upregulated ANXA1 expression may be associated with carcinogenesis,progression,invasion and metastasis of GAC.This protein could be considered as a biomarker of clinical prognostic prediction and targeted therapy of GAC.     

Serum screening for detection of high-risk group for early-stage diffuse type gastric cancer in Japanese

Background and Aim: Serum screening systems are beneficial for gastric cancer mass surveys; however, the marker for diffuse type gastric cancer (DGC) is not defined. We attempted to define the high‐risk group for DGC by using serum markers of anti‐Helicobacter pylori antibody and pepsinogens (PG). Methods: Forty‐two patients in the early stage of DGC and 511 controls were enrolled. Fasting serum samples were collected, and anti‐H. pylori antibody and PG were evaluated. The risk for DGC was calculated. Results: The prevalence of DGC was higher in H. pylori‐positive patients (odds ratio [OR] = 4.3 in men, 9.6 in women). DGC prevalence was significantly higher in the PG1+ group in women (OR = 10.7); however, it was lower in the PG3+ group in both men and women. Patients with PG II ≥ 30 revealed a significantly higher risk for DGC. By combining factors, higher OR (OR = 12.5 in men, 42.7 in women) were obtained when we defined the risk group as H. pylori‐positive, PG‐negative, and having PG II ≥ 30. Conclusion: The risk group for DGC can be defined by evaluating ordinary serum gastritis markers.     

Detection of disseminated tumor cells in bone marrow of gastric cancer using magnetic activated cell sorting and fluorescent activated cell sorting

Background and Aim: Magnetic activated cell sorting (MACS) and fluorescent activated cell sorting (FACS) were employed to enrich and detect the gastric cancer cells from a cell line in a model system, and to enrich and detect disseminated tumor cells (DTCs) from bone marrow (BM) of patients with gastric cancer. Methods: Fifteen patients with benign gastric lesions and 35 patients with gastric cancer who received curative operations between December 2002 and June 2003 were selected. Mononuclear cells were separated from their BM. Cells from cell line OCUM‐2M were seeded with 10‐grade ratio into mononuclear cells from patients with benign gastric lesion. After labeling by MACS minibeads conjugated with cytokeratin (CK) 7/8 antibodies, anti‐CK‐fluorescein isothiocyanate (FITC), and anti‐CD45‐perdinin chlorophyll protein (PerCP), the samples were enriched twice using an MS+/RS+ positive separation column. The FACS analysis was conducted on these samples before and after MACS enrichment. The results were analyzed using clinopathological parameters. Results: Disseminated tumor cells were detected in the BM of 25 (71.43%) patients with gastric cancer. The frequencies of DTCs were 1.38 × 10^?8–2.40 × 10^?5, 2.19 × 10^?7–3.70 × 10^?5, 4.01 × 10^?6–8.57 × 10^?5 in patients with well, moderately, and poorly differentiated carcinoma, respectively (P = 0.026). Disseminated tumor cells in BM had close correlation with tumor tumor‐node‐metastasis (TNM) stage (P = 0.034) and cancer‐free survival (P = 0.035). Conclusion: Disseminated tumor cells are very common in the BM of gastric cancer patients. Poor histological differentiation and more advanced TNM stage have more DTCs in the BM of gastric cancer patients. Patients with DTCs tend to have a poor prognosis.     

Down-regulation of plasma membranous Annexin A1 protein expression in premalignant and malignant lesions of the oral cavity: correlation with epithelial differentiation

Purpose  To determine the potential involvement of ANXA1 in oral squamous-cell carcinoma (OSCC), we evaluated the ANXA1 protein expression in oral premalignant lesions (OPLs) and OSCCs and correlated the results with clinicopathologic variables. Methods  Matched normal and tumour specimens of 44 primary OSCCs and 28 OPLs were analyzed for ANXA1 subcellular localization and protein expression level by immunohistochemistry (IHC). Correlations between ANXA1-IHC staining scores of OSCCs and clinicopathologic features were evaluated by Fisher’s exact test. Results  Markedly down-regulation of ANXA1 protein expression was identified on the plasma membrane of epithelial cells in OSCCs (P < 0.001) and OPLs (P = 0.001) compared with normal counterparts. Moreover, loss of plasma membranous ANXA1 expression was significantly correlated with the poorly differentiated status of OSCC cells (P = 0.012). Conclusions  Our findings suggest that loss of ANXA1 is frequent and early event during oral carcinogenesis and that ANXA1 could contribute to maintaining epithelial differentiation in OSCC.     

Prognostic relevance and therapeutic implications of centromere protein F expression in patients with esophageal squamous cell carcinoma

Centromere protein F (CENP‐F), a cell cycle‐regulated centromere protein, has been shown to affect numerous tumorigenic processes. This study aimed to clarify the prognostic significance of CENP‐F expression in patients with esophageal squamous cell carcinoma (ESCC). The levels of CENP‐F messenger RNA and protein were higher in ESCC cell lines than in the normal tissues. An immunohistochemical analysis of paired tissue specimens showed that the CENP‐F expression was higher in tumorous tissues than in the adjacent non‐tumorous tissues (P < 0.001). Moreover, there was a significant correlation between CENP‐F expression and gender (P = 0.012), clinical stage (P = 0.039), and T classification (P = 0.026). Patients with higher CENP‐F expression had shorter overall survival than those with lower CENP‐F expression (P = 0.009). Multivariate Cox analysis indicated that CENP‐F expression is an independent prognostic factor for overall survival (hazard ratio = 0.582, 95% confidence interval = 0.397–0.804, P = 0.041). Importantly, it was found that zoledronic acid (ZOL) could significantly enhance the chemotherapeutic sensitivity of ESCC cell lines with high CENP‐F expression to cisplatin, although ZOL alone only exhibited a minor inhibitory effect to ESCC cells. In summary, these findings demonstrate that CENP‐F may serve as a valuable molecular marker for predicting the prognosis of ESCC patients. In addition, the data indicate a potential benefit of combining ZOL with cisplatin in ESCC, suggesting that CENP‐F expression may have therapeutic implications.     

Reduction of syndecan-1 expression in differentiated type early gastric cancer and background mucosa with gastric cellular phenotype

Background Syndecan-1 is known to play a role as a cell adhesion molecule, similar to E-cadherin, and is associated with the maintenance of epithelial morphology. The purpose of this study was to elucidate the role and alterations of syndecan-1 expression in comparison with those of E-cadherin in different cellular phenotypes of differentiated-type gastric cancers (DGCs).Methods A total of 80 DGCs at an early stage, and their adjacent mucosa, were evaluated by both immunohistochemistry and in situ hybridization. Syndecan-1 and E-cadherin were assessed by immunohistochemical staining with an anti-syndecan-1 and an anti-E-cadherin antibody, respectively. Based on immunohistochemistry, DGCs and their surrounding mucosa were divided into four types: gastric type (G-type), ordinary type (O-type), complete-intestinal type (CI-type), and null type.Results The expression sites of syndecan-1 mRNA mostly coincided with those of syndecan-1 protein. Syndecan-1 expression was significantly lower in G-type cancers (30%) than in O- (81%) and CI-type cancers (92%) (P = 0.0001 and P = 0.004, respectively), but E-cadherin did not show this result. In addition, syndecan-1 expression was significantly reduced in DGCs comprised partly of poorly differentiated adenocarcinoma or signet-ring cell carcinoma, compared to DGCs demonstrating papillary and/or tubular adenocarcinoma (P = 0.02). G-type intestinal metaplasia (IM) surrounding the tumors was observed in 21% of G-type cancers, in 0% of O-, and in 10% of CI-type cancers (P = 0.01; G-type vs O-type). Reduction of syndecan-1 expression was significant in G-type IM (25%) compared to non-G-type IM (75%; P = 0.02).Conclusions Syndecan-1 plays a role in the growth of G-type cancers at an early stage compared with E-cadherin changes, and the reduction of syndecan-1 expression in IM surrounding the tumors may influence the growth of G-type cancer.     

Expression and distribution of protein translation initiation factor C2 gene in hepatocellular carcinoma and gastric cancer tissue

OBJECTIVE: To study the expression, distribution and significance of the C2 gene in hepatocellular carcinoma (HCC) and gastric cancer tissue. METHODS: The avidin‐biotin‐peroxidase complex (ABC) immunohistochemical method was used to detect the expression of C2 protein in 60 specimens of HCC and 58 specimens of gastric cancer tissue, and the western blot technique was used to detect the expression of C2 protein in 10 specimens of HCC and associated pericancerous tissue. RESULTS: In 60 specimens of HCC and 42 specimens of associated pericancerous tissue, the rates of C2 protein detection were 27.3 and 83.3%, respectively; the latter being significantly greater than the former (P < 0.001). The expression of C2 protein was significantly correlated with the patient's age, HBsAg and α?fetoprotein (AFP; P < 0.05). The findings from western blotting were consistent with those from immunohistochemical methods. The rate of C2 protein detection was 20.4% in 49 specimens of HCC that were hepatitis‐B virus encoded X antigen (HBxAg)‐positive, but 63.6% in 11 HCC specimens that were HbxAg‐negative. The rate of C2 protein detection was significantly lower in HbxAg‐positive tissue than in HbxAg‐negative tissue (P < 0.05). In 58 specimens of gastric cancer tissue and 44 specimens of associated pericancerous tissue, the rates of C2 protein detection were 41.4 and 77.3%, respectively. The rate was significantly higher in gastric cancer tissue than in associated pericancerous tissue (P < 0.05), and C2 protein detection was significantly correlated with pathological grading, tumor size and the depth of invasion (P < 0.05). CONCLUSIONS: Low expression of the C2 gene might be involved in the development of HCC and gastric cancer. The suppression of C2 by HBxAg may play an important role in the development of HCC. C2 may be a potential tumor suppression gene.     

Fhit,E‐cadherin,p53, and activation‐induced cytidine deaminase expression in endoscopically resected early stage esophageal squamous neoplasia

Background and Aim: Abnormal expression of Fragile Histidine Triad (Fhit), E‐cadherin and p53 is observed in esophageal squamous cell carcinoma. It has recently been reported that aberrant expression of activation‐induced cytidine deaminase (AID) in gastric epithelium leads to the accumulation of nucleotide alterations in the p53 gene. However, little is known about the association between these molecular events and the clinicopathological characteristics of early stage esophageal squamous neoplasia, especially in endoscopically resected tumors. Methods: Esophageal squamous neoplasias (n = 49) comprising nine cases of low‐grade intraepithelial neoplasia (LGIN), 22 of high‐grade intraepithelial neoplasia/carcinoma in situ (HGIN/CIS) and 18 of invasive cancers, were endoscopically resected. Their expression of the tumor‐related proteins: Fhit, E‐cadherin, p53 and AID was assessed using immunohistochemical methods, and the relationship between protein expression and clinicopathological data was examined. Results: Reduced or absent Fhit and E‐cadherin expression was detected in 22% and 0% of LGIN cases, 73% and 14% of HGIN/CIS cases, and 94% and 61% of invasive cancer cases, respectively, showing progressive increases during neoplastic progression (Fhit: P < 0.01, E‐cadherin: P < 0.01). Although p53 and AID were overexpressed in these samples, no change in their expression occurred during neoplastic progression. Moreover, p53 expression was not significantly associated with AID expression. Conclusions: These results indicate that a decrease in Fhit and E‐cadherin expression could be related to the development and progression of esophageal squamous neoplasia, and that the expression of p53 was independent of aberrant AID expression in the early stage of esophageal carcinogenesis.     

MUC6 down-regulation correlates with gastric carcinoma progression and a poor prognosis: an immunohistochemical study with tissue microarrays

Purpose MUC6 was first discovered by screening a gastric mucosa cDNA library and is expressed in the mucous cells of the neck zone and antral glands of the stomach. The aim of the present study was to clarify whether down-regulation has any clinicopathological or prognostic significance in gastric neoplasia.Methods Expression of MUC6, MUC5AC and MUC2 was examined using tissue microarrays for immunohistochemistry in gastric carcinomas (n = 225), adenomas (n = 40), and normal mucosa (n = 89) and compared with clinicopathological parameters and survival data.Results MUC6 expression was lower in gastric carcinomas than in adenomas or normal mucosa (P < 0.05) and inversely correlated with tumor size, depth of invasion, lymphatic and venous invasion, lymph node metastasis and UICC staging (P < 0.05). Positive links with expression of MUC2 and MUC5AC were noted (P < 0.05). MUC6 expression was lower in diffuse-type than intestinal-type lesions (P < 0.05). Kaplan–Meier analysis indicated that cumulative survival of patients with no MUC6 expression was significantly lower than with weak, moderate or strong expression in all and even advanced gastric carcinoma (P < 0.05). Multivariate analysis showed three independent prognostic factors, depth of invasion, lymphatic and venous invasion, to concordantly affect the relationship between MUC6 expression and prognosis.Conclusions Down-regulation of MUC6 may contribute to malignant transformation of gastric epithelial cells and underlie the molecular bases of growth, invasion, metastasis and differentiation of gastric carcinoma. Altered expression might therefore be employed as an indicator of pathobiological behaviors and prognosis of gastric carcinoma.     

Altered Expression of a Li-Cadherin in Gastric Cancer and Intestinal Metaplasia

The aims of this study were to examine Li-cadherin expression in 74 gastric carcinoma tissues, 10 cases with normal gastric tissues, and 21 cases with intestinal metaplasia and to investigate the role of Li-cadherin in cell differentiation, cancer invasion, and metastasis. Expression of Li-cadherin was analyzed by immunohistochemistry and semiquantitative polymerase chain reactio and correlated with clinicopathological parameters. Immunohistochemistry showed that Li-cadherin was mainly present on the cell membrane and there was no staining for liver–intestine cadherin in normal tissues. The reduction of Li-cadherin mRNA expression was inversely correlated with the grade of differentiation (P < 0.05). Significant differences in the expression of liver–intestine cadherin were found in lymphatic metastasis of the tumors (P < 0.05), but the expression of liver–intestine cadherin was not associated with gender (P=0.748), serosal invasion (P=0.136), TNM stage (P=0.172), Helicobacter pylori infection (P=0.572), liver metastasis (P=0.374), or peritoneal metastasis (P=0.621). Multivariate analysis revealed that the expression of Li-cadherin is an important predictor of lymph node metastasis. We conclude that there is a significant correlation between Li-cadherin expression and the differentiation of gastric carcinoma, and Li-cadherin can be a good marker to detect gastric cancer at early stages. Increased Li-cadherin expression may contribute to gastric cancer invasion to lymph nodes.     

Interleukin-1B and interleukin-1 RN polymorphisms and gastric carcinoma risk: a meta-analysis

Background and Aim: We aimed to explore the role of interleukin (IL)‐1B cluster gene polymorphisms at positions ?511, ?31, and +3954 and the receptor IL‐1RN variable number tandem repeat polymorphisms in the susceptibility to gastric carcinoma through a systematic review and meta‐analysis. Methods: Each initially included article was scored for quality appraisal. The desirable data were extracted and registered into databases. Studies that deviated from Hardy–Weinberg equilibrium were excluded. Eighteen studies were ultimately eligible for the meta‐analysis of IL1B–511, 21 studies for IL1B‐31, 10 studies for IL1B+3954, and 20 studies for IL1RN variable number tandem repeat genetic polymorphisms, respectively. Original groups were collapsed and re‐grouping was adopted in line with the most probably appropriate genetic models. Potential sources of heterogeneity were sought out via stratification and sensitivity analyses, and biases across studies were estimated. Results: The pooled odds ratios (95% confidence intervals, P‐value) associated with IL‐1B ?511 T carriers versus CC genotypes and with RN *2 carriers versus L/L were 1.23 (1.04–1.45, P = 0.015) and 1.26 (1.06–1.51, P = 0.010), respectively, for overall gastric carcinoma; 1.31 (1.04–1.64, P = 0.020) and 1.47 (1.21–1.79, P = 0.000), respectively, for non‐cardia gastric cancer; 1.55 (1.05–2.28, P = 0.026) and 1.66 (1.23–2.25, P = 0.001), respectively, for intestinal type gastric carcinoma; and 1.33 (1.04–1.71, P = 0.023) and 1.31 (1.07–1.61, P = 0.010), respectively, in Caucasians for overall gastric carcinoma. The pooled odds ratio (95% confidence interval, P‐value) regarding IL‐1B?31 CC plus TT versus CT was 0.73 (0.60–0.89, P = 0.002) for intestinal type gastric carcinoma. Genotyping methods and publication time could constitute the sources of heterogeneity across studies. Publication biases were not found. Conclusion: IL‐1B ?511 T allele and IL‐1 RN *2 VNTR are significantly associated with an increased risk of developing gastric carcinoma and even more significantly with non‐cardia gastric carcinoma or with intestinal‐type gastric carcinoma. Both are significantly associated with an increased risk of developing gastric carcinoma among Caucasians, but not among Asians or Hispanics.     

High microsatellite instability predicts good prognosis in intestinal-type gastric cancers

Background and Aim: A subset of gastric cancers showed high microsatellite instability (MSI‐H). The reported clinicopathological features of MSI‐H gastric cancers are heterogeneous, and specific factors associated with prognosis have not been identified. Methods: We analyzed the clinicopathological characteristics and prognostic factors in a large series (161 cases) of MSI‐H gastric cancers, and compared the results to 315 cases of microsatellite‐stable or low microsatellite‐instable gastric cancers. Results: The frequency of MSI‐H gastric cancers was 9% (161/1786). MSI‐H gastric cancers have distinct clinicopathological features, including female sex, older age, antral location, well‐to‐moderate differentiation, intestinal‐type Lauren classification, expanding‐type Ming classification, a non‐signet‐ring cell component, the presence of a mucinous component, a moderate‐to‐severe lymphoid stromal reaction, and a lower tumor stage. The MSI‐H phenotype was associated with better prognosis (P = 0.044), and male sex (P = 0.035, hazard ratios [HR]: 0.23), intestinal‐/mixed‐type Lauren classification (P < 0.001, HR: 0.09) and lower tumor stages (1 and 2, P = 0.001, HR: 0.08) were independently‐favorable prognostic factors. Conclusions: With unique clinicopathological features, intestinal‐type MSI‐H gastric cancers are associated with good prognosis and can be classified as a different subset of gastric cancers.     

Androgen receptor (AR) expression is an independent unfavorable prognostic factor in gastric cancer

Purpose To investigate the expression of sex steroid receptors in gastric cancer and to correlate their tumor expression profile with the clinicopathological parameters and overall survival of the patients.Methods Immunohistochemical methodology was employed in formalin-fixed paraffin-embedded sections from 86 patients with gastric carcinoma. Monoclonal antibodies against androgen (AR), estrogen (ER), and progesterone (PR) receptors were used. Survival rates were estimated by the Kaplan-Meier method and compared using the log-rank test. Multivariate analysis was performed by the Cox proportional hazards model.Results Fifteen (17.4%) cases of gastric adenocarcinomas were positive for AR, two (2.3%) were positive for PR and three (3.5%) were positive for ER. Significantly higher AR expression was found in tumors with metastases to lymph nodes (P = 0.03). Patients with AR-positive tumors (AR+) had worse prognosis than (AR-) patients (median survival 9 months vs 24 months, P = 0.03). Patients with AR- and heat shock protein 27 (HSP27)-positive tumors (AR+/HSP27+) had a median survival of 6 months, whereas (AR-/HSP27-) patients had a median survival of 42 months (P = 0.017). Multivariate analysis revealed that AR expression and UICC stage were independent factors of unfavorable prognosis (P = 0.037 and P = 0.0055, respectively).Conclusions Identification of AR-positive gastric carcinomas in gastric biopsies may warrant a more aggressive therapeutic approach and anti-androgen or AR-targeted agents may represent a novel strategy in tackling this devastating malignancy.     

Decreasing concentration of interstitial glucose in REM sleep in subjects with normal glucose tolerance

Aims Sleep is divided into two major stages, non‐rapid eye movement (NREM) and rapid eye movement (REM), which are distinct in various neuroendocrine respects. NREM/REM cycles influence insulin and glucagon secretion; however, glucose concentrations in REM compared with NREM have not been directly explored. The aim was to investigate the differences in glucose concentrations in interstitial fluid (IGC) between NREM/REM cycles using a continuous glucose monitoring system (CGMS). Methods Thirteen subjects were eligible for analysis out of the 28 enrolled. All underwent standard polysomnography for the assessment of sleep stages and the exclusion of sleep apnoea syndrome with CGMS and subsequent morning oral glucose tolerance test (exclusion of glucose intolerance or diabetes). Results The IGC in REM fell in 12 out of the 13 subjects, whereas the IGC in NREM increased in eight out of the 13 subjects. Therefore, the mean change of IGC differed in direction between sleep stages: ?0.028 (?0.045 to ?0.011) for REM vs. 0.005 (?0.012 to 0.017) for NREM [median (QR), P = 0.007, n = 13], with the mean difference of 0.038 mmol/l × 5 min^?1 (95% confidence interval 0.012, 0.064). The mean glucose concentration in REM sleep was lower than in NREM: 4.29 ± 1.00 vs. 4.53 ± 0.90 mmol/l (mean ± sd , P = 0.003, n = 13). Conclusions The decrease in IGC in REM compared with NREM sleep, with lower absolute values, may arise from different physiological events observed in these sleep stages. The REM‐related decline in glucose concentrations may be a risk factor for nighttime hypoglycaemia.     

Expression and clinical significance of CD73 and hypoxia-inducible factor-1α in gastric carcinoma

AIM: To investigate the expression of CD73 and hypoxia-inducible factor-1α (HIF-1α) in human gastric carcinoma, and explore their clinical significance and prognostic value. METHODS: CD73 and HIF-1α expressions were detected by immunohistochemistry in consecutive sections of tissue samples from 68 gastric carcinoma patients. The peritumor tissues 2 cm away from the tumor were obtained and served as controls. The presence of CD73 and HIF-1α was analyzed by immunohis-tochemistry using the Envision technique. RESULTS: CD73 and HIF-1α expressions in gastric carcinoma were significantly higher than those in gastric mucosal tissues as control (P < 0.001) and showed a close correlation (Spearman r = 0.390, P = 0.001). Overexpression of CD73 was positively correlated with differentiation of tumor (P = 0.000), histopathology (P = 0.041), depth of invasion (P < 0.001), nodal status (P = 0.003), metastasis (P = 0.013), and the American Joint Committee on Cancer (AJCC) stage (P < 0.001). High expression of HIF-1α was positively correlated with tumor diameter (P = 0.031), depth of invasion (P = 0.022), and AJCC stage (P = 0.035). The overall survival rate was low in the patients with high expression of CD73 (P < 0.001). Moreover, CD73+/HIF-1α+ patients had the worst prognosis (P < 0.001). CD73 expression was proven to be an independent predictor for patients with gastric carcinoma by both multivariate Cox regression analysis (P = 0.021) and receiver operating characteristic curves (P = 0.001).CONCLUSION: CD73 expression correlates closely with HIF-1α expression in gastric carcinoma. CD73 could be an independent prognostic indicator for gastric carcinoma.     

Bcl-2 expression and allelic loss of thep53 gene in gastric carcinomas

In order to clarify the association betweenbcl-2 protein (Bcl-2) expression and genetic alteration, we investigatedp53 andDCC (deleted in the colon carcinoma gene locus) gene abnormalities in Bcl-2-positive and-negative gastric carcinomas using a polymerase chain reaction/loss of heterozygosity (LOH) assay. Bcl-2 immunoreactivity was found in 25 of 178 (14%) gastric carcinoma cases. With these 25 positive cases, the proportion 18/87 (20.6%) of the total in early stages demonstrating invasion of the mucosa and/or submucosa was significantly greater (P=0.013) than the 7/91 (7.7%) found for advanced tumors exhibiting invasion into or through the muscularis propria. However, there was no statistically significant variation between the proportions for differentiated (17/98 cases, 17.3%) and undifferentiated (8/80 cases, 10%) lesions. Sixteen Bcl-2-positive cases (9 cases were not studied because of insufficient specimen material to allow extraction of DNA) and 31 cases randomly selected from a Bcl-2-negative group were analyzed for the presence ofp53-LOH or DCC-LOH and forp53 by immunohistochemistry. The minority of the Bcl-2-positive group hadp53-LOH and were immunopositive for p53 (P=0.033,P=0.028 respectively), while no association was found in the Bcl-2-negative category. In contrast, there was no correlation at all between Bcl-2 expression and DCC-LOH although the number of informative cases analyzed was too small to allow definite conclusions. These results indicate that Bcl-2 may be predominantly expressed at an early stage in gastric carcinomas, possibly in negative association withp53 gene abnormalities.Abbreviations DCC deleted in colon carcinoma gene locus - LOH loss of heterozygosity - PCR polymerase chain reaction - VNTR variable number of tandem repeats     

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.     

Abnormal DNA-PKcs and Ku 70/80 expression may promote malignant pathological processes in gastric carcinoma

AIM:To determine the expression of the catalytic subunit of DNA-dependent protein kinase(DNA-PKcs)and the Ku70/Ku80 heterodimer(Ku 70/80)in gastric carcinoma.METHODS:Gastric biopsies were obtained from 146gastric carcinoma patients[Helicobacter pylori(H.pylori)-negative:89 and H.pylori-positive:57]and 34from normal subjects(H.pylori-negative:16 and H.pylori-positive:18)via surgery and endoscopic detection from April 2011 to August 2012 at the First Affiliated Hospital of Nanchang University.Pathological diagnosis and classification were made according to the criteria of the World Health Organization and the updated Sydney system.An‘‘in-house’’rapid urease test and modified Giemsa staining were employed to detect H.pylori infection.The expression of DNA-PKcs and the Ku 70/80protein was detected by immunohistochemistry.RESULTS:Overall,the positive rates of both DNA-PKcs and Ku 70/80 were significantly increased in gastric cancer(χ2=133.04,P<0.001 for DNA-PKcs andχ2=13.06,P<0.01 for Ku)compared with normal gastric mucosa.There was hardly any detectable expression of DNA-PKcs in normal gastric mucosa,and the positive rate of DNA-PKcs protein expression in patients with a normal gastric mucosa was 0%(0/34),whereas the rate in gastric cancer(GC)was 93.8%(137/146).The difference between the two groups was statistically significant.Additionally,the positive rate of Ku 70/80 was79.4%(27/34)in normal gastric mucosa and 96.6%(141/146)in gastric cancer.The DNA-PKcs protein level was significantly increased in gastric cancer(MannWhitney U=39.00,P<0.001),compared with normal gastric mucosa.In addition,there was a significant difference in the expression of Ku 70/80(Mann-Whitney U=1117.00,P<0.001)between gastric cancer and normal gastric mucosa.There was also a significant difference in Ku70/80 protein expression between GC patients with and without H.pylori infection(P<0.05).Spearman analysis showed a negative correlation between tumor differentiation and DNA-PKcs expression(r=-0.447,P<0.05).Moreov