Impact of catheter-tissue contact force on lesion size during right ventricular outflow tract ablation in a swine model / 中华医学杂志(英文版)

BACKGROUND@#The catheter-tissue contact force (CF) is one of the significant determinants of lesion size and thus has a considerable impact on the effectiveness of ablation procedures. This study aimed to evaluate the impact of CF on the lesion size during right ventricular outflow tract (RVOT) ablation in a swine model.@*METHODS@#Twelve Guangxi Bama miniature male pigs weighing 40 to 50 kg were studied. After general anesthesia, a ThermoCool SmartTouch contact-sensing ablation catheter was introduced to the RVOT via the femoral vein under the guidance of the CARTO 3 system. The local ventricular voltage amplitude and impedance were measured using different CF levels. We randomly divided the animals into the following four groups according to the different CF levels: group A (3-9 g); group B (10-19 g); group C (20-29 g); and group D (30-39 g). Radiofrequency ablations were performed at three points in the free wall and septum of the RVOT in power control mode at 30 W for 30 s while maintaining the saline irrigation rate at 17 mL/min. At the end of the procedures, the maximum depth, surface diameter, and lesion volume were measured and recorded. A linear regression analysis was performed to determine the relationship between continuous variables.@*RESULTS@#A total of 72 ablation lesions were created in the RVOT of the 12 Bama pigs. The maximum depth, surface diameter, and volume of the lesions measured were well correlated with the CF (free wall: β = 0.105, β = 0.162, β = 3.355, respectively, P < 0.001; septum: β = 0.093, β = 0.150, β = 3.712, respectively, P < 0.001). The regional ventricular bipolar voltage amplitude, unipolar voltage amplitude, and impedance were weakly positively associated with the CF (β = 0.065, β = 0.125, and β = 1.054, respectively, P < 0.001). There was a significant difference in the incidence of steam pops among groups A, B, C, and D (free wall: F = 7.3, P = 0.032; septum: F = 10.5, P = 0.009); and steam pops occurred only when the CF exceeded 20 g. Trans-mural lesions were observed when the CF exceeded 10 g in the free wall, while the lesions in the septum were non-trans-mural even though the CF reached 30 g.@*CONCLUSIONS@#CF seems to be a leading predictive factor for the size of formed lesions in RVOT ablation. Maintaining the CF value between 3 and 10 g may be reasonable and effective for creating the necessary lesion size and reducing the risk of complications, such as steam pops and perforations.

Inhibitory effect of metformin on aldehyde dehydrogenase positive gastric cancer stem cells and its mechanism / 解放军医学杂志

Objective To investigate the inhibitory effect of metformin (Met) on ALDH positive (ALDH+) gastric cancer stem cells and its mechanism.Methods ALDH+ and ALDH cells were isolated from human gastric cancer cell line MKN45 by flow cytometry.The characteristics of cancer stem cells of ALDH+ cells was verified by self-renewing ability,differentiation capacity experiments and tumorigenicity in nude mice.1mmol/L Met group,5mmol/L Met group and control group (MKN45 cell) were set up.After being acted on MKN45 cell for 48h,the proportion ofALDH+ cells in each group was detected by flow cytometry.RT-PCR test was performed to detect the expression of Oct4,Sox2 and AKT genes in the 3 groups.Results The cell identification showed that the self-renewal ability,differentiation capacity and tumorigenicity of ALDH+ cells were higher than that of ALDH-cells.Drug experiments indicated that the proportion ofALDH+ cells in control group,lmmol/L Met group and 5mmol/L Met group were 36.5％ ± 5.4％,15.6％ ± 1.9％ and 7.6％ ± 1.6％,respectively.The difference between the 3 groups was statistically significant (P＜0.01).RT-PCR revealed that the expressions of Sox2 and AKT genes decreased after Met treatment,and decreased with the increase of Met concentration.The expression of Oct4 gene was higher in 1 mmol/L Met group than in control group,and was lower in 5mmol/L Met group than in control group.Conclusion Met may inhibit the growth ofALDH+ gastric cancer stem cells and the expression ofAKT gene,and can be used as a target drug for the clinical treatment of gastric cancer.

Treatment of super obesity by laparoscopic Roux-en-Y gastric bypass: experience of 42 cases / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility and efficacy of laparoscopic Roux-en-Y gastric bypass(LRYGB) for super obesity(BMI≥50 kg/m(2)).</p><p><b>METHOD</b>Clinical data of 42 patients undergoing LRYGB in the First Affiliated Hospital of Jinan University between 2004 and 2008 were analyzed retrospectively.</p><p><b>RESULTS</b>All the LRYGB procedures were successfully performed with no conversion to open surgery. Average operation time was 145.1 minutes, volume of blood loss during the surgery was 25.0 ml, and length of postoperative hospital stay was 9.9 days. The cases were followed up for 1 month to 30 months. Body weight and BMI decreased significantly 1 month after the operation and reached a minimum level after 2 years then became stable while excess body weight loss rate(EWL) increased(P<0.05). All the obese-related symptoms were relieved significantly. Four cases(9.5%) showed complications during perioperative period including 1 case of respiratory failure, 2 cases of gastrojejunal anastomotic bleeding, 1 case of umbilical wound infection, and 11 developed long-term complications. All of them were cured by conservative treatment.</p><p><b>CONCLUSIONS</b>Treatment of super obesity by LRYGB is feasible with significant short-term results. But due to the difficulty of the operation and postoperative complications, comprehensive treatment from experienced bariatric surgical team is needed. The long-term outcome needs for further observation.</p>

The effect of mitochondrial oxidative stress and the expression of Bcl-2 and Bax proteins on cardiomyocyte apoptosis during hypoxia postconditioning / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate mitochondrial oxidative stress on cardiomyocyte apoptosis and the expression of Bcl-2 and Bax proteins in cardiac sarcolemma and mitochondria after application of hypoxia postconditioning and free radical scavengers.</p><p><b>METHODS</b>Primary cultured neonatal rat cardiomyocytes were exposed to 3 h hypoxia (H) followed by (1) 6 h of reoxygenation (R) (H/R), (2) 3 intermittent cycles of 5 min H and R before 6 h of R (PC), (3) application of superoxide dismutase (SOD) before PC (SOD+PC), (4) application of catalase (CAT) before PC (CAT+PC), and (5) application of SOD plus CAT before PC (SOD+CAT+PC). Cardiac sarcolemma and mitochondria were isolated by differential centrifugation. Mitochondrial reactive oxygen species (ROS) was detected with fluorescent probes (DCFH-DA) and cardiomyocyte apoptosis was detected with flow cytometry. The expressions of Bcl-2 and Bax proteins in cardiac sarcolemma and mitochondria were measured by Western blot.</p><p><b>RESULTS</b>Mitochondrial ROS reduced significantly in PC, SOD+PC, CAT+PC and especially in SOD+CAT+PC groups (all P<0.01). The number of apoptotic cardiomyocytes reduced significantly in PC, SOD+PC and CAT+PC (all P<0.01) but not in SOD+CAT+PC groups. Bcl-2 levels increased while Bax levels decreased in cardiac sarcolemma and mitochondria in PC, SOD+PC and CAT+PC groups (all P<0.01), Bcl-2 levels decreased and Bax levels increased in H/R and PC+SOD+CAT groups (all P<0.01).</p><p><b>CONCLUSIONS</b>PC attenuated H/R induced ROS and cardiomyocyte apoptosis, which might be mediated by upregulating the expression of Bcl-2 and downregulating the Bax in mitochondria and sarcolemma; SOD or CAT alone did not but SOD plus CAT attenuate the anti-apoptotic effect of hypoxia postconditioning; mitochondrial ROS thus plays an important role in PC's cardioprotection.</p>

Isolation and characterization of side population cells in human gastric cancer cell line BGC-823 / 中华肿瘤杂志

<p><b>OBJECTIVE</b>Isolate and characterize the side population (SP) cells with potency of stem cells from human gastric carcinoma cell line BGC-823.</p><p><b>METHODS</b>SP and non-SP cells were sorted from BGC-823 cells by fluorescence-activated cell sorting (FACS) using Hoechst33342 staining. The tumorigenic ability of the SP cells was assessed by in vivo transplantation into non-obese diabetic/severe combined immunodeficiency mice.</p><p><b>RESULTS</b>SP cells were isolated from BGC-823 cells in a proportion of 0.9% to 2.1% with respect to the whole cell population. The colony formation assay showed that the colony formation rate of the SP cells was significantly higher than that of the non-SP cells (72.56% vs. 49.00%, P < 0.01). The drug sensitivity test showed that the SP cells showed stronger drug resistance to 5-Fu than the non-SP cells. The in vivo transplantation of SP cells in mice showed that the tumor weight was (0.176 ± 0.034) g, significantly higher than that of non-SP cells (0.045 ± 0.046) g (P < 0.01).</p><p><b>CONCLUSIONS</b>The results of this study indicate the existence of cancer stem-like SP cells in the human gastric cancer line BGC-823 cells. Further characterization of this SP cell population may provide new insights for diagnosis and treatment of gastric cancer.</p>

A novel set of surgical instruments facilitate the procedure of laparoscopic pyeloplasty / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Open pyeloplasty has been historically described as the gold standard for the surgical treatment of ureteropelvic junction obstruction (UPJO), even if new techniques have recently gained a prominent role in this field. Laparoscopic pyeloplasty (LP) is not widely prevelant because of the technically challenging nature and it represents the gold standard for UPJO only in expert hands. To overcome some difficulties and technical challenges encountered during pure laparoscopic pyeloplasty, we designed a set of new instruments and assessed them using porcine model.</p><p><b>METHODS</b>According to the ideas from the surgeons, our medical engineer designed three new instruments, including the right angle laparoscopy scissors, the petal-shape ureter dilator and the guide tube. Four experienced laparoscopic experts were involved in a no survival porcine study to assess the help of these new instruments. Four experiments were conducted on live pigs that weighed 22 to 25 kg at the same time. After general anesthesia was administered, transperitoneal ureteroureterostomy was performed using standard laparoscopic instruments, including placing the double J stent anterograde. Then, the opposite lateral was done by the same surgeon plus these new devices for side-by-side comparative analysis. All experts were interviewed to assess these new instruments by the questionnaire based on the visual analog scale (VAS) from 1 (none) to 10 (very much).</p><p><b>RESULTS</b>The procedures were all technically successful. The right angle laparoscopy scissors and the guide tube were accepted by all participants and the Help Score were 6.75 and 4.25 respectively, at the same time the New Difficulty Score 1.25 and 1.75. However, the petal-shape ureter dilator got 1.5 Help Score and 6.5 New Difficulty Score. These surgeons made a negative comment and one of surgeons recommended the stone basket was more suitable.</p><p><b>CONCLUSION</b>The right angle laparoscopy scissors and the guide tube may be helpful to minimize some difficulties in pure laparoscopic pyeloplasty.</p>

Antecolic versus retrocolic gastroenteric anastomosis for laparoscopic Roux-en-Y gastric bypass: a prospective randomized control trial / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To compare short-term postoperative outcomes between antecolic and retrocolic laparoscopic Roux-en-Y gastric bypass(LRYGB).</p><p><b>METHODS</b>Forty obesity patients were admitted into The First Affiliated Hospital of Jinan University from March 2008 to July 2010. All patients were randomly assigned to undergo antecolic (group A, 20 cases) and retrocolic (group B, 20 cases) gastroenteric anastomosis. Short-term outcomes were compared.</p><p><b>RESULTS</b>LRYGB procedures were successfully performed in all the 40 patients. There were no significant differences between the two groups in estimated blood loss during surgery, time to flatus passage, time to resumption of oral intake, or length of postoperative hospital stay. The operation time was longer in group B than that in group A [(163.4±28.1) min vs.(131.8±22.7) min, P<0.05]. There were no patients developed internal hernia or anastomotic leakage in either group. Comparison of short-term gastrointestinal symptoms after surgery showed no statistical significance.</p><p><b>CONCLUSIONS</b>Although retrocolic procedure may be closer to anatomical structure, antecolic and retrocolic anastomosis have comparable short-term outcomes after surgery. Further study is warranted to investigate long-term outcomes.</p>

Significance of soluble DLL1 in diagnosis of intracranial infectious diseases in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the significance of soluble DLL1 (Delta-like-1) levels of cerebrospinal fluid (CSF) and serum in the diagnosis of intracranial infection in children.</p><p><b>METHODS</b>Fifty children with intracranial infection, including 20 cases of tuberculous meningitis (TM), 20 cases of viral meningitis (VM) and 10 cases of purulent meningitis (PM), and 20 children without intracranial infection (control group) were enrolled. The levels of soluble DLL1 in CSF and serum were measured using ELISA.</p><p><b>RESULTS</b>The level of CSF soluble DLL1 in the TM group was significantly higher than that in the VM, PM and control groups (2.89 ± 1.72 ng/mL vs 0.14 ± 0.14 ng/mL, 0.27 ± 0.21 ng/mL, 0.13 ± 0.12 ng/mL; P<0.01). The level of serum soluble DLL1 in the TM group was also significantly higher than that in the VM, PM and control groups (12.61 ± 6.45 ng/mL vs 2.28 ± 2.27 ng/mL, 2.38 ± 1.79 ng/mL, 2.26 ± 2.10 ng/mL; P<0.01). The levels of soluble DLL1 in the CSF and serum in the VM and PM groups were not significantly different from those in the control group.</p><p><b>CONCLUSIONS</b>Soluble DLL1 as a novel indicator might have potentially important value in the diagnosis of TM.</p>

Treatment of obesity and type 2 diabetes mellitus by laparoscopic Roux-en-Y gastric bypass / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the efficacy of laparoscopic Roux-en-Y gastric bypass (LRYGB) in the treatment for obesity and type 2 diabetes mellitus (DM).</p><p><b>METHODS</b>Twenty-one cases of obesity and 9 cases of type 2 DM received the LRYGB. Weigh changes, excess body weight lose rate (EWL%) and blood glucose level were measured after surgery and occurrence of complications was observed postoperatively.</p><p><b>RESULTS</b>LRYGB procedures in all the 30 cases were successfully performed with no conversion to open surgery. Average operation time was 168 minutes (110-270 mins), volume of blood loss during the surgery was 24.0 ml (10-75 ml). Twenty-one cases of simple obesity received follow-up from 2 months to 5 years. Body weight and BMI decreased significantly in one month [(85.1+/-10.1) kg vs (97.2+/-15.0) kg, 31.2+/-2.2 vs 35.3+/-3.5, both P<0.01] and to a minimal level in 2 to 3 years [(66.8+/-9.2) kg, 24.3+/-1.1], and then maintained at this level. EWL% was correspondingly higher (all P<0.05). Nine type 2 DM patients were followed up for 3 to 8 months, fasting blood glucose and blood glucose OGTT2 hours decreased significantly [(5.9+/-1.4) mmol/L vs (12.6+/-2.6) mmol/L, (7.8+/-1.4) mmol/L vs (17.8+/-4.1) mmol/L, both P<0.05], of whom 4 patients with obesity decreased in BMI significantly (P<0.05), and 5 patients without obesity had no significant changes in BMI (P>0.05). Five cases (16.7%) had postoperative complications, including 1 case of death due to acute fulminant pancreatitis, 1 case of mesenteric hiatal hernia with obstruction in line for reoperation, and the other 3 cases of healing by conservative therapy.</p><p><b>CONCLUSIONS</b>Treatment of obesity and type 2 DM by LRYGB surgery is feasible with significant short term result. Long term outcome needs further observation.</p>

Laparoscopic Roux-en-Y gastric bypass surgery for treatment of type 2 diabetes mellitus / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the surgical approach, feasibility and effectiveness of laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery for treating type 2 diabetes mellitus.</p><p><b>METHODS</b>Seven obese patients with type 2 diabetes and 5 type 2 diabetic patients without obesity received LRYGB surgery. The changes of the body mass, fasting blood glucose (FBG), 2-hour postprandial blood glucose (2 h PBG), C peptide (C-P) and HbA1c% were observed postoperatively.</p><p><b>RESULTS</b>LRYGB procedures were successfully performed in all the 12 patients with no conversion to open surgery. The resolution rate was 85.7% in the obese group and 80% in the non-obese diabetic group.</p><p><b>CONCLUSION</b>LRYGB surgery is feasible for treatment of type 2 diabetes with good short-term result, but the long-term outcome awaits further observation.</p>

Mitochondrial connexin43 and postconditioning protection in rabbits underwent myocardial ischemia/reperfusion injury / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the roles of mitochondrial connexin43 (Cx43) and mitochondrial ATP sensitive potassium channe1 (mitoK(ATP)+) in the postconditioning protection for rabbits underwent myocardial ischemia/reperfusion injury.</p><p><b>METHODS</b>In anesthetized open-chest rabbits, the left anterior descending artery (LAD) was occluded for 30 min and reperfused for 4 h and randomly divided into four groups (n = 16 each): sham operation group (Sham), ischemic reperfusion group (IR), ischemic postconditioning group (PC) and PC plus 5-HD, a specific mitoK(ATP)+ inhibitor (PC + 5-HD). Rabbits were sacrificed post 4 h reperfusion. Heart rate and the mean arterial pressure were recorded and plasma CK-MB and cTnI activity were measured at baseline, at the end of ischemia, and after 2 h and 4 h of reperfusion, respectively. Myocardial infarct size was determined and mitochondria structure was observed under electron microscope at the end of the experiment. Mitochondria were isolated and the protein content of the mitochondrial Cx43 was determined by Western blot.</p><p><b>RESULTS</b>Plasma CK-MB, cTnI activity and myocardial infarct size were significantly reduced in PC [(19.1 +/- 3.9)%] group compared to IR [(35.7 +/- 5.8)%] and PC + 5HD [(34.2 +/- 3.9)%] groups (all P < 0.01). Degree of mitochondria damage was significantly reduced in PC group compared to IR and PC + 5HD groups (all P < 0.01). The mitochondria Cx43 content was significantly decreased in IR group and PC + 5-HD group compared to sham group (all P < 0.05) and restored in PC group.</p><p><b>CONCLUSION</b>Ischemic postconditioning protected the heart from I/R injury by improving mitochondrial ultrastructure and by attenuating I/R induced decrease of mitochondria Cx43 expression. The protective effects of postconditioning was partly mediated by activating mitoK(ATP)+ pathway.</p>

Endoscopic thyroidectomy via the areola of breast approach / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility and safety of endoscopic thyroidectomy via the areola of breast approach.</p><p><b>METHODS</b>Between April 2005 to September 2008, endoscopic thyroidectomy via the areola of breast approach was performed in 28 female patients. Of the patients, 25 cases presented with nodular goiter, 2 cases with Grave's disease and 1 case with minimum papillary carcinoma. The average age was 22.5 years (range, 18-38 years). A 10 mm trocar was placed on the medial border of the areola of the right breast for the video-endoscopy and removing specimens, and a 5 mm trocar was placed on the lateral border of the areola of the same breast as the assisted operation hole. Another 5 mm trocar was placed on the medial border of the areola of left breast as the main operation hole. The operation data was recorded and analyzed.</p><p><b>RESULTS</b>All the 28 operations were successful. The procedures included one lobe total thyroidectomy in 5 cases, one lobe subtotal thyroidectomy in 15 cases, subtotal thyroidectomy in 3 cases, one lobe near total thyroidectomy + the other lobe subtotal thyroidectomy in 4 cases, and one lobe total thyroidectomy + the central group lymph node resection + the other lobe subtotal thyroidectomy in 1 case. The average operation time was 60.7 minutes (range, 40-125 minutes), the average operation blood loss was 5.8 ml (range, 2-15 ml), the average length of post-operative hospital stay was 3.1 days (range, 2-5 days). No adverse effects was found after the operation, such as damage to the parathyroid gland and the laryngeal nerve. The patients were followed-up for 1 to 40 months with satisfactory results. All 28 patients were satisfied with the cosmetic effects of the operation.</p><p><b>CONCLUSIONS</b>Endoscopic thyroidectomy via the areola of breast approach produces an outstanding cosmetic effect, it is safe and feasible.</p>

Altered expression of PTEN gene and LOH of its epigenetic microsatellite in gastric carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the expression of PTEN and loss of heterozygosity (LOH) of its epigenetic microsatellite in gastric carcinoma and explore their roles in progression of gastric carcinoma.</p><p><b>METHODS</b>LOH of epigenetic microsatellites of PTEN (D10S541, D10S583 and D10S1687) in advanced gastric cancer was detected by PCR-SSCP. Expression of PTEN mRNA and protein in normal gastric mucosa and gastric cancer was evaluated by RT-PCR and SABC immunohistochemistry, respectively. The relationship between expression of PTEN mRNA and protein and lymph node metastasis or LOH of microsatellites was discussed.</p><p><b>RESULTS</b>LOH of D10S541, D10S583 and D10S1687 was found in 37.5% (21/56) of advanced gastric cancers. The positive rates of PTEN mRNA expression were 80.4% (45/56), 45.5% (5/11) and 32.1% (18/56) in normal mucosa, early and advanced gastric carcinomas, respectively, while 78.6% (44/56), 44.5% (5/11) and 28.6% (16/56) at the protein level. PTEN mRNA and protein were less frequently expressed in early and advanced gastric carcinomas than that in normal gastric mucosa (P < 0.05). There was positive correlation between PTEN mRNA expression and LOH of microsatellites in advanced gastric carcinomas. PTEN protein expression paralleled with its mRNA expression (P < 0.05). The expression of PTEN mRNA and protein was negatively correlated with lymph node metastasis of advanced gastric carcinomas (P < 0.05).</p><p><b>CONCLUSION</b>Down-regulated expression of PTEN gene is found in different stages of gastric carcinoma, and is closely correlated with LOH of its epigenetic microsatellites, which probably is its underlying molecular mechanisms. It suggests that altered PTEN gene contributes to tumorigenesis and progression of gastric carcinomas.</p>

Expression of maspin and kai1 and their clinicopathological significance in carcinogenesis and progression of gastric cancer / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the roles of maspin and kai1 expression in tumorigenesis and progression of gastric cancer.</p><p><b>METHODS</b>Maspin and kai1 expressions were detected in normal gastric mucosa (n = 182), gastric dysplasia (n = 69), and gastric cancer (n = 113) by immunohisto-chemistry. Their expressions were compared with clinicopathological parameters of tumors. Relationship between maspin and kai1 expression was also concerned in gastric cancer.</p><p><b>RESULTS</b>The positive rates of maspin expression were 79.8% (145/182), 75.4% (52/69), and 50.4% (57/113) in normal gastric mucosa, gastric dysplasia, and gastric cancer, while those of kai1 expression were 81.9% (149/182), 65.2% (49/69), and 58.4% (66/113) in corresponding tissues respectively. Gastric cancer less frequently expressed maspin than the normal gastric mucosa and gastric dysplasia (P < 0.05), while dysplasia and cancer showed less frequent expression of kai1 than normal mucosa (P < 0.05). Maspin expression showed negative association with invasive depth, metastasis, Lauren's and histological classifications (P < 0.05), but not with tumor size, Borrmann's classification, growth pattern or TNM staging (P > 0.05). Kai1 expression was negatively correlated with invasive depth, metastasis, growth pattern, Lauren's and histological classifications (P < 0.05), but not with tumor size, Borrmann's classification or TNM staging (P > 0.05). Maspin and kai1 were collaboratively expressed in gastric cancer (P < 0.05).</p><p><b>CONCLUSIONS</b>Down-regulated expressions of maspin and kai1 play an important role in gastric carcinogenesis. Abnormal expression of maspin and kai1 might have inhibitory effects on invasion and metastasis of gastric cancer and act as an effective and objective marker to indicate the pathobiological behaviors of gastric cancer.</p>

Expression of PTEN-encoding product in different stages of carcinogenesis and progression of gastric carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To illustrate the significance of expression of phosphatase and tensin homologue derived from chromosome ten (PTEN) encoding product in normal mucosa, intestinal metaplasia (IM), dysplasia and carcinoma of the stomach, and to evaluate its clinical implication in tumorigenesis and progression of gastric carcinoma.</p><p><b>METHODS</b>Formalin-fixed and paraffin-embedded tissues from 184 cases of gastric carcinoma, its adjacent normal mucosa, IM and dysplasia were evaluated for the expression of PTEN by SABC immunohistochemistry. PTEN expression was assessed as to tumor stage, lymph node metastasis, Lauren's classification and WHO histological classification of gastric carcinoma. Expression of VEGF protein was also studied in 60 cases of gastric carcinoma, with its correlation with PTEN concerned.</p><p><b>RESULTS</b>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 stomach, respectively. The positive rates in the last two groups were lower than the first two (P < 0.01). PTEN was less expressed in advanced gastric carcinoma than in early ones (42.9% vs 67.6%, P < 0.01). The positive rate of PTEN protein was lower in gastric carcinoma with lymph node metastasis than without (40.3% vs 63.3%, P < 0.01). PTEN was less expressed in diffuse-type gastric carcinoma than in intestinal-type (41.5% vs 57.8%, P < 0.05). Signet ring cell carcinoma expressed PTEN stood the lowest (25.0%, 7/28), which was less than well and moderately differentiated ones (61.8%, 21/34) (P < 0.01). Expression of PTEN was inversely correlated with expression of VEGF though without any significance (P > 0.05).</p><p><b>CONCLUSION</b>Loss or reduced expression of PTEN protein is common in carcinogenesis and progression of gastric cancer. Altered expression of PTEN may contribute to carcinogenesis and progression of gastric cancer by increasing angiogenesis, cellular adhesion and mobility and so on. PTEN may be an objective marker for pathologically biological behavior of gastric carcinoma.</p>