Underwater endoscopic mucosal resection for neoplasms in the pyloric ring of the stomach: Four case reports

BACKGROUND Tumors located in the pylorus are technically more complex to resect by endoscopic resection,as the anatomical characteristics of this region can affect the adequate assessment of margins and performance of the procedure.We reported the results of underwater endoscopic mucosal resection(UEMR)of benign mucosal neoplasms located in the pyloric ring.CASE SUMMARY This case series describes 4 patients with 4 mucosal neoplasms located in the pyloric ring.The diameter of each neoplasm was less than 15 mm.We performed UEMR for the lesions.Water immersion enabled slight floating of the lesions,resulting in easy identification.We achieved en bloc resection with a snare and electrosurgical unit.All procedure were performed within 3 min without adverse events.Pathologic examination showed low-grade dysplasia with clear resection margins in one case and hyperplastic polyps in three cases.CONCLUSION UEMR can be an effective and safe treatment method for neoplasms in the gastric pyloric ring.

Experimental study on effect of recombinant human growth hormone combined with chemotherapy on stomach neoplasms implanted in nude mice

Objective: To investigate the effect of different doses of recombined growth hormone (rhGH) on stomach neo- plasms implanted in nude mice, and its efficacy in combining with chemotherapy (flurouracil, 5-FU). Methods: Human stom- ach neoplasms model was established in nude mice. The nude mice were divided into control group, moderate-dose of rhGH group, low-dose rhGH group, 5-FU group, moderate-dose rhGH/5-FU group, and low-dose rhGH/5-FU group. The results of each group were observed after ten days. Results: After therapy, the body mass of rhGH groups was significantly increased compared with control group (P<0.05), the body mass of rhGH/5-FU groups was significantly increased compared with 5-FU group (P<0.05), but it was no significant difference between rhGH/5-FU groups and control group (P>0.05). The average tumor mass and volume of rhGH groups were not significantly increased compared with control group (P>0.05), but they were significantly reduced in 5-FU group and rhGH/5-FU groups (P<0.05). They were no significant difference between rhGH/5- FU groups and 5-FU group (P>0.05). After treatment, the percentages of S, G0/G1 and G2/M phases and proliferation index (PI) were not significantly changed in rhGH groups compared with control group (P>0.05), and the same with rhGH/5-FU groups compared with 5-FU group (P>0.05). The difference caused by dose of rhGH was not significant. Conclusion: rhGH enhances body mass, does not stimulate tumor growth, and has no adverse effects on tumor bearing nude mice. Combined with flurouracil, rhGH does not influence the efficacy of chemotherapy, and has no effect on tumor cell cycle kinetics.

Extremely well-differentiated adenocarcinoma of the stomach: Clinicopathological and immunohistochemical features

AIM： Minimal deviation carcinoma of the uterine cervix, otherwise known as extremely well-differentiated adenocarcinoma （EWDA）, is characterized by its benign microscopic appearance in contrast to its aggressive behavior. In order to elucidate the clinicopathological features and biological behavior of the gastric counterpart of EWDA, we, using immunohistochemistry, analyzed nine lesions for the phenotypic expression, proliferative activity, and the expression of oncogene-associated products. METHODS： Clinicopathological features, including preoperative biopsy diagnosis, were reviewed. Using immunohitstochemistry, Ki-67 labeling index and expression of p53 and c-erbB-2 protein in the gastric lesions were detected.RESULT： Locations in the middle or upper third of the stomach and polypoid macroscopic features are characteristic of EWDA of the stomach. Although 4 of the 9 lesions showed only focal lymphatic or venous invasion, lymph node metastasis was not present and none of the patients died of the lesions （mean follow-up period, 56 too）. All 9 cases of EWDA could be classified into gastric phenotype （5 lesions） and intestinal phenotype （4 lesions）. The former resembled gastric foveolar epithelium, mucous neck cells or pyloric glands, but their papillary structures were frequently elongated and the tumor cellsand their nuclei were slightly larger and more hyperchromatic compared to normal epithelium. The latter resembled intestinal metaplasia with minimal nulcear atypia and irregular glands; two of these lesions demonstrated complete intestinal phenotype, while two demonstrated incomplete intestinal phenotype. Ki-67 labeling index was low and none of the cases revealed over-expression of p53 and c-erbB-2 protein. CONCLUSION： Unlike minimal deviation carcinoma of the cervix, these findings suggest that EWDA of the stomach is a lesion of low-grade malignancy. This favorable biological behavior is supported by the data of a low Ki-67 labeling index and a lack of p53 or c-erbB-2 protein over-expression. Because of its resemblance to normal gastric mucosa or mucosa with intestinal metaplasia, EWDA is often misdiagnosed. To prevent the misdiagnosis of such lesions, the clinical and pathologic characteristics should be taken into consideration.

Proton pump inhibitors and stomach neoplasm

This study aimed to explore the relationship between proton pump inhibitors(PPIs)and gastric tumors and determine the reasons behind these connections.We reviewed studies on PPIs and stomach tumors.We explored the relationship between PPIs and different types of gastric neoplasms according to the classification of gastric neoplasms.Long-term use of PPIs is associated with stomach infection,high gastrin levels,and rebound acid hypersecretion,which are directly or indirectly related to the development of gastric neoplasms.PPIs can increase the risk of gastric fundal polyps.Further evidence is needed to prove that it can increase the risk of gastric cancer.

Metastatic stomach lymphoepithelioma-like carcinoma and immune checkpoint inhibitor therapy:A case report

BACKGROUND Pulmonary lymphoepithelioma-like carcinoma(PLELC)is a rare type of nonsmall-cell lung cancer.Stomach lymphoepithelioma-like carcinoma(LELC)metastasis secondary to PLELC has not been reported recently.CASE SUMMARY A 64-year-old female was admitted to our hospital for a regular gastroscopy examination with a 6-year history of surgical resection for left PLELC.Positron emission tomography/computed tomography suggested high accumulation of 18F-fludeoxyglucose in the gastric cardia region.Upper gastrointestinal endoscopy confirmed a large mass at the stomach fundus.Immunohistochemistry(IHC)of the biopsy suggested metastatic stomach LELC.Proximal gastrectomy showed that this 6.5 cm×5.0 cm mass was located in the stomach fundus near the cardia.Histopathological examination showed a poorly differentiated carcinoma with prominent lymphoplasmacytic infiltration.IHC demonstrated that the tumor was positive for CK(AE1/AE3),p63,p40,p53,Ki-67(70%),and EGFR(3+)and negative for CK7,CK20,Her2,and CD10.In situ hybridization analysis showed positive staining Epstein-Barr virus-encoded RNA.Tumor programmed cell death ligand 1(PD-L1)expression score was 98%,and the combined positive score was 100,with no evidence of microsatellite instability.Thus,the patient was unequivocally diagnosed with metastatic stomach LELC secondary to pulmonary LELC.After discharge,this patient underwent PD-1 inhibitor treatment(toripalimab,240 mg)every 3 wk for ten cycles,and she has had no tumor recurrence.CONCLUSION For gastric LELC metastasis,PD-1 inhibitor therapy could become a new therapeutic approach,though there is still no evidence from large data sets to support this.

Gastric leiomyoma presenting as an endophytic growth of cardia of the stomach: A case report

Gastric leiomyomas are rare submucosal neoplasms arising from smooth muscle cells.It accounts for approximately 2.5%of all gastric tumours,is slow growing and rarely causes symptoms such as upper abdominal discomfort and dyspepsia.1 On imaging,they appear similar to gastrointestinal stromal tumours(GISTs)and can be intraluminal or extraluminal.Diagnosis is mostly confirmed by histopathological examination of the tumour.Surgical resection of the tumour is the main treatment option.Here,we present a case of laparoscopic resection of an endophytic gastric tumour that turned out to be a leiomyoma.

Clinico-pathologic significance of neuroendocrine cells in gastric carcer tissue

AIMS To elucidate the biological and clinicopathological signifi- cance of neuroendocrine(NE)cells in gastric carcinoma(GC). METHODS One hundred and eighty-nine cases of various histo- logical types of GC were observed using light microscopy, histochemistry,immunohistochemistry and electron microscopy. Of them 127 patients were followed up. RESULTS Chromogranin A(CgA)positive GC was demonstrat- ed in 85 cases(45.0%).The typos of NE cells in GC were probed using 9 kinds of hormone antibodies 49 cases(67.2%) contained more than one hormone.NE cells were found more often in poorly differentiated GC than in well differentiated ones(P<0. 01).Expression of some kinds of hormone Was relative to the dif- ferentiation and histological types of GC.BOM,CT(P<0.01) GAST and 5-HT(P<0.05)were more expressed in poorly differ- entiated cases than in well defferentiated ones.Nineteen cases of the matastatic foci in regional lymph nodes were found to have CgA positive cancer cells.The presence of HCG in matastatic lymph nodes was more often observed than that of other hormone (P<0.01).The survival rate of patients with NE positive GC was 38.9% and negative GC 52.7%.Five of 7 patients(71. 4%)with somatostatin positive GC still survived at follow up of 33-66 months,but 4 patients with HCG positive GC died in 12-29 months. CONCLUSIONS The NE cells occur more frequently in poorly differentiated GC.Certain hormones appear to be related to the metastasis and prognosis.

Clinicopathological analysis of patients with gastric cancer in 1200 cases

INTRODUCTIONGastric cancer is one of the most common fatal malignancies in the world. The prognosis is generally poor in advanced gastric cancer .The low survival is related to delayed diagnosis, metastasis and recurrence after operation .The aim of this paper was to find correlation between clinical factors was to find correlation between clinical factors and biologic behavior of gastric cancer in a series of 1200 patients undergoing surgical resection.

Clinicopathologic factors and molecular markers related to lymph node metastasis in early gastric cancer

AIM: To analyze predictive factors for lymph node metastasis in early gastric cancer.METHODS: We analyzed 1104 patients with early gastric cancer(EGC) who underwent a gastrectomy with lymph-node dissection from May 2003 through July 2011. The clinicopathologic factors and molecular markers were assessed as predictors for lymph node metastasis. Molecular markers such as microsatellite instability, human mut L homolog 1, p53, epidermal growth factor receptor(EGFR) and human epidermal growth factor receptor 2(HER2) were included. The χ2 test and logistic regression analysis were used to determine clinicopathologic parameters.RESULTS: Lymph node metastasis was observed in 104(9.4%) of 1104 patients. Among 104 cases of lymph node positive patients, 24 patients(3.8%) were mucosal cancers and 80 patients(16.7%) were submucosal. According to histologic evaluation, the number of lymph node metastasis found was 4(1.7%) for well differentiated tubular adenocarcinoma, 45(11.3%) for moderately differentiated tubular adenocarcinoma, 36(14.8%) for poorly differentiated tubular adenocarcinoma, and 19(8.4%) for signet ring cell carcinoma. Of 690 EGC cases, 77 cases(11.2%) showed EGFR overexpression. HER2 overexpression was present in 110 cases(27.1%) of 406 EGC patients. With multivariate analysis, female gender(OR = 2.281, P = 0.009), presence of lymphovascular invasion(OR = 10.950, P < 0.0001), diameter(≥ 20 mm, OR = 3.173, P = 0.01), and EGFR overexpression(OR = 2.185, P = 0.044) were independent risk factors for lymph node involvement.CONCLUSION: Female gender, tumor size, lymphovascular invasion and EGFR overexpression were predictive risk factors for lymph node metastasis in EGC.

Inhibitory effects of RRR-α-tocopheryl succinate on benzo (a) pyrene (B (a) P)-induced forestomach carcinogenesis in female mice

AIM To study the inhibitory effects of VES( RRR-α-tocopheryl Succinate, VES ), aderivative of natural Vitamin E, on benzo (a)pyrene (B (a) P)-induced forestomach tumor infemale mice.METHODS The model of B (a)P-inducedforestomach tumor was established according tothe methods of Wattenberg with slightmodifications. One hundred and eighty femalemice (6 weeks old) were divided into six groupsequally; negative control (Succinic acid),vehicle control ( Succinate + B (a) P), positivecontrol(B(a) P), high VES(2.5g/kg. b. w + B(a)P), Iow VES(1 .25 g/kg. b. w + B(a) P) ig as wellas VES by ip (20 mg/kg, b. w + B(a) P). Exceptthe negative control group, the mice wereadministrated with B(a)P ig. and correspondingtreatments for 4 weeks to study the anti-carcinogenetic effect of VES during the initiationperiod. The experiment lasted 29 weeks, inwhich the inhibitory effects of VES both ontumor incidence and tumor size were tested.RESULTS The models of B (a)P-inducedforestomach tumor in female mice wereestablished successfully. Some werecauliflower-like, others looked like papilla, evena few were formed into the ulcer cavities. VES at1.25 g/kg. b. w, 2.5 g/kg. b.w. by ig and 20 mg/kg. b. w. via ip could decrease the number oftumors per mouse (1.7 ± 0. 41, 1.6 ± 0.34 and 1.1±0.43), being lower than that of B(a)P group(5.4 ± 0.32, P＜0.05). The tumor incidence wasinhibited by 18.2%, 23.1% and 50.0%. VES at1.25g/kg.b.w., 2.5 g/ kg.b.w. by ig and20 mg/kg. b.w. via ip reduced the total volumeof tumors per mouse (54.8 ± 8.84, 28.4 ± 8.32and 23.9± 16.05), being significantly lower thanthat of B(a)P group (150.2±20.93, P＜0.01).The inhibitory rates were 63.5%, 81.1% and84.1%, respectively.CONCLUSION VES has inhibitory effects on B(a) P-induced forestomach carcinogenesis infemale mice, especially by ip and it may be apotential anti-cancer agent in vivo.

Annual cost of illness of stomach and esophageal cancer patientsin urban and rural areas in China： A multi-center study

Objective： Stomach and esophageal cancer are imposing huge threats to the health of Chinese people whereasthere were few studies on the financial burden of the two cancers.Methods： Costs per hospitalization of all patients with stomach or esophageal cancer discharged betweenSeptember 2015 and August 2016 in seven cities/counties in China were collected, together with their demographicinformation and clinical details. Former patients in the same hospitals were sampled to collect information onannual direct non-medical cost, indirect costs and annual number of hospitalization. Annual direct medical cost wasobtained by multiplying cost per hospitalization by annual number of hospitalization. Annual cost of illness （ACI）was obtained by adding the average value of annual direct medical cost, direct non-medical cost and indirect cost,stratified by sex, age, clinical stage, therapy and pathologic type in urban and rural areas. Costs per hospitalizationwere itemized into eight parts to calculate the proportion of each part. All costs were converted to 2016 US dollars（1 USD：6.6423 RMB）.Results： Totally 19,986 cases were included, predominately male. Mean ages of stomach cancer and urbanpatients were lower than that of esophageal cancer and rural patients. ACI of stomach and esophageal cancerpatients were $10,449 and $13,029 in urban areas, and $2,927 and $3,504 in rural areas, respectively. Greater ACIwas associated with male, non-elderly patients as well as those who were in stage I and underwent surgeries.Western medicine fee took the largest proportion of cost per hospitalization.Conclusions： The ACI of stomach and esophageal cancer was tremendous and varied substantially among thepopulation in China. Preferential policies of medical insurance should be designed to tackle with this burden andfurther reduce the health care inequalities.

Current gene therapy for stomach carcinoma

Gastric cancer is common in China [1-42],and its early diagnosis and treatment in advanced stage are difficult [31-50].In recent years ,gene study in cancer is a hotspot ,and great progress has been achieved [41-80] .Cancer gene therapy has shifted from the imagination into the laboratory and clinical trials.

EXPRESSION OF MASPIN AND KAI1 AND THEIR CLINICOPATHOLOGICAL SIGNIFICANCE IN CARCINOGENESIS AND PROGRESSION OF GASTRIC CANCER

To investigate the roles of maspin and kai1 expression in tumorigenesis and progression of gastric cancer. Methods 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. Results 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 histo-logical 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). Conclusions 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 effe-ctive and objective marker to indicate the pathobiological behaviors of gastric cancer.

Intensify standardized therapy for esophageal and stomach cancer in tumor hospitals

INTRODUCTIONCancer treatment situation in tumor hospitals inChina has its own unique characteristics which arenot found in other parts of the world. Because ofthe huge population and high incidence rates ofesophageal and stomach cancer[1-5], the number ofcancer patients waiting for admission isinconceivably large.

Exophytic inflammatory myofibroblastic tumor of the stomach in an adult woman:A rare cause of hemoperitoneum

Inflammatory myofibroblastic tumor （INT） of the stomach in adults is extremely rare, with unpredictable prognosis. We present a 55-year-old woman with a gastric IMT. She experienced sudden abdominal pain 4 d previously. Physical examination showed mild abdominal tenderness in the hypogastrium, but no palpable abnormal abdominal mass. Abdominal CT showed a mass of approximately 8 cm in the gastrocolic ligament. On laparoscopic exploration, unexpected hemoperitoneum of approximately 1.5 L of blood was found, and an exophytic gastric mass of approximately 10 cm, appeared from the anterior wall of the gastric body along the greater curvature. Laparoscopy further showed that non- clotting blood in the abdominal cavity seemed to be from the gastric tumor. After conversion to open surgery for more precise evaluation of the cause of hemoperitoneum and the large friable tumor, gastric wedge resection, including the tumor, was conducted. The final diagnosis was consistent with IMT that originated from the gastric wall.

Correlation of integrin β3 mRNA and vascular endothelial growth factor protein expression profiles with the clinicopathological features and prognosis of gastric carcinoma

AIM： To investigate integrin β3 mRNA and vascular endothelial growth factor （VEGF） protein expression in gastric carcinoma, and its correlation with microvascular density, growth-pattern, invasion, metastasis and prognosis. METHODS： In situ hybridization（ISH） of integrin β3 mRNA and immunohistochemistry of VEGF and CD34 protein were performed on samples from 118 patients with gastric cancer. RESULTS： The positive rate of integrin β3 mRNA in non-tumor gastric mucosa （20%） was significantly lower than that of the gastric cancer tissue （52.5%, X^2 = 10.20, P 〈 0.01）. In patients of infiltrating type, stage T3-T4, vessel invasion, lymphatic metastasis, hepatic or peritoneal metastasis, the positive expression rates of integrin β3 mRNA were significantly higher than those in patients of expanding type （P 〈 0.01）, stage T1-T2 （P 〈 0.01）, non-vessel invasion （P 〈 0.01）, without lymphatic metastasis （P 〈 0.01）, without hepatic and peritoneal metastasis （P 〈 0.01）, respectively. In patients of infiltrating type, stage T3-T4, vessel invasion, lymphatic metastasis, hepatic or peritoneal metastasis, the positive expression rates of VEGF protein were significantly higher than those in patients of expanding type （P 〈 0.01）, stage T1-T2 （P 〈 0.01）, non-vessel invasion （P 〈 0.01）, without lymphatic metastasis （P 〈 0.01）, without hepatic and peritoneal metastasis （P 〈 0.01）, respectively. In patients of infiltrating type, stage T3-T4, vessel invasion, lymphatic metastasis, hepatic or peritoneal metastasis, the mean MVD were significantly higher than those in patients of expanding type （P 〈 0.01）, stage T1-T2 （P 〈 0.01）, non-vessel invasion （P 〈 0.01）, without lymphatic metastasis （P 〈 0.01）, without hepatic and peritoneal metastasis （P 〈 0.01）, respectively. It was found that the positive expression rate of integrin β3 mRNA was positively related to that of VEGF protein （P 〈 0.01） and MVD （P 〈 0.05）, meanwhile the positive expression rate of VEGF protein was positively related to MVD （P 〈 0.05）. The mean survival period in patients with positive expression of integrin β3 mRNA and VEGF, and MVD ≥54.9/mm^2 was significantly shorter than that in patients with negative expression of integrin β3 mRNA （P 〈 0.05） and VEGF （P 〈 0.01）, and MVD 〈 54.9/mm^2 （P 〈 0.01）. Five-year survival rate in patients with positive expression of integrin β3 mRNA and VEGF, and MVD ≥54.9/mm^2 was significantly lower than those with negative expression of integrin β3 mRNA （P 〈 0.05）, VEGF （P 〈 0.05）, and MVD 〈 54.9/mm^2 （P 〈 0.01）. CONCLUSION： Integrin β3 and VEGF expression can synergistically enhance tumor angiogenesis, and may play a crucial role in invasion and metastasis of gastric carcinoma. Therefore, they may be prognostic biomarkers and novel molecular therapeutic targets.

Classification of gastric neuroendocrine tumors and its clinicopathologic significance

AIMS To study the pathologic classification of gastric neuroendocrine tumors and its clinicopathologic significance. METHODS Paraffin embedded sections of 52 gastric neuroendocrine tumors including 42 carcinoid tumors, and 10 cases of neuroendocrine carcinoma from 326 patients who underwent resection of stomach carcinomas were studied by immunohistochemical methods including 10 endocrine markers or hormones antibodies and endocrine cells in gastric neuroendocrine tumors and extratumoral mucosa were observed under electromicroscope. RESULTS The 52 gastric neuroendocrine tumors were divided into three types: ① Gastrin dependent type of carcinoid (26 cases) accompanied by chronic atrophic gastritis (CAG) and tumor extension limited to the mucosa or submucosa complicated with hypergastrinemia and G cell hyperplasia. This type was consistently preceded by and associated with generalized proliferation of endocrine cells in the extratomoral fundic mucosa. ② Non gastrin dependent type of carcinoids (16 cases) associated with neither CAG nor hypergastrinemia. This type was more aggressive; and ③ Neuroendocrie carcinomas (10 cases), which are highly aggressive tumors. CONCLUSIONS A correct identification of different types of gastric endocrine tumors has major implications for the treatment and prognosis of the patients.

Unusual gastric tumors and tumor-like lesions: Radiological with pathological correlation and literature review

Although gastric tumors have overlapping radiologic appearances, some unusual tumors may present specific imaging features. Using multidetector computed tomography(MDCT), with water as a negative oral contrast agent and intravenous contrast medium, can provide critical information for the diagnosis of gastric diseases. In addition, MDCT can evaluate the involvement of the gastric wall and extragastric extent of the disease, as compared with gastroenteroscopy and double-contrast upper gastrointestinal study. Regarding lesion location and size, enhancing and growth patterns, presence of calcification or fat, and involvement of the gastric wall and adjacent structures, CT may provide useful information. In this review article, we review the relevant literature and discuss the CT features and the histopathologic findings of different types of gastric lesions. The lesions are divided into benign(glomus tumors, schwannomas, leiomyomas, and lipomas), malignant(gastrointestinal stromal tumors, mucinous carcinomas, lymphomas, and carcinoid tumors), and tumor-like lesions(ectopic pancreas and bezoar). Familiarity with imaging appearances and pathologic findings can help physicians make an accurate diagnosis.

Relationship between Preoperative Clinicopathologic Characteristics and Lymph Node Metastasis in Early Gastric Cancer

Objective： To investigate the features of the preoperative clinicopathologic characteristics in correlation with lymph node metastasis. Methods： The preoperative clinicopathologic characteristics and lymph node metastasis of 265 patients with early gastric carcinoma were analyzed retrospectively. Results： The three clinicopathologic characteristics, maximum cancer diameter 〉2cm under endoscope, poor differentiation and excavated type were significant high risk independent preoperative clinicopathologic characteristics （P〈0.05） . The patients who had none of the three preoperative clinicopathologic characteristics had no lymph node metastasis, while 27.27% of the patients who had all the three preoperative clinicopathologic characteristics had N2 lymph node metastasis. Conclusion： The three preoperative clinicopathologic charaeteristics, maximum cancer diameter under endoscope, cell differentiation and gross type were very useful to evaluate the extent of lymph node metastasis.

Study on the pathogenetic effect of salted pork from a high risk area of stomach cancer in China

AIM To study the pathogenetic effect of salted pork (SP) (special food in Zhuanghe City, a high risk area of stomach cancer in northern China) on stomach cancer, and provide scientific basis for primary prevention of stomach cancer in this high risk area. METHODS The study consisted of three parts. The first part was to study the mutagenicity of SP. The Ames test and micro nuclei assay of V 79 cell were employed in this part. The second part was to study the effect of SP on the gastric mucosa of residents in Zhuanghe area who had consumed SP for more than 10 years and the dose effect relations between SP and pathological changes of gastric mucosa. A total of 300 cases were analysed. The third part was to study the mucosal lesions of experimental dogs by gastroscopy and mucosal biopsy. Six healthy male dogs were chosen, three were fed with SP, and the others served as control. RESULTS In this study, the results showed that the extract of SP could lead to mutation of Salmonella typhimurium TA 98 and induce the increase of micro nuclei rate (MNR) and micro nuclei cell rate (MNCR) of V 79 at a dose range of 20～80μl/ml. There were dose effect relations between SP, MNR, MNCR. Pathological changes of gastric mucosa of local residents who had consumed SP showed significant difference from those of the control group. In people who had consumed SP for 10 years, mucosal lesions including necrosis and erosion were found; in those who consumed SP for 10～20 years, hyperplasia and dysplasia were also seen besides the above lesions and those for 20～30 years, severe dysplasia and even malignant changes could be observed. SP had damaging effect on the gastric mucosa of dogs fed with SP. The mucosal lesions became more severe with increasing feeding time. CONCLUSION SP is a strong mutagen and long term exposure to SP may result in repeated gastric mucosal damage and repair, and finally leading to severe dysplasia and malignancy.