Do Gastric Signet Ring Cell Carcinomas and ECL-Cell Neuroendocrine Tumours Have a Common Origin?

Gastric cancer is a heterogenous group of tumours, and a better understanding of the carcinogenesis and cellular origin of the various sub-types could affect prevention and future treatment. Gastric neuroendocrine tumours (NETs) and adenocarcinomas that develop in the gastric corpus and fundus of patients with chronic atrophic gastritis have atrophic gastritis, hypoacidity, and hypergastrinemia as common risk factors and a shared cellular origin has been suggested. In particular, signet ring cell carcinomas have previously been suggested to be of neuroendocrine origin. We present a case of a combined gastric NET and signet ring cell carcinoma in a patient with hypergastrinemia due to autoimmune chronic atrophic gastritis. The occurrence of such a combined tumour strengthens the evidence that gastric NETs and signet ring cell carcinomas develop from a common origin.

Transpancreatic biliary sphincterotomy versus double guidewire in difficult biliary cannulation: a randomized controlled trial.

BACKGROUND: Difficult biliary cannulation in endoscopic retrograde cholangiopancreatography (ERCP) increases the risk of post-ERCP pancreatitis (PEP). The purpose of this prospective, randomized, multicenter study was to compare two advanced rescue methods, transpancreatic biliary sphincterotomy (TPBS) and a double-guidewire (DGW) technique, in difficult common bile duct (CBD) cannulation. METHODS: Patients with native papilla and planned CBD cannulation were recruited at eight Scandinavian hospitals. An experienced endoscopist attempted CBD cannulation with wire-guided cannulation. If the procedure fulfilled the definition of difficult cannulation and a guidewire entered the pancreatic duct, randomization to either TPBS or to DGW was performed. If the randomized method failed, any method available was performed. The primary end point was the frequency of PEP and the secondary end points included successful cannulation with the randomized method. RESULTS: In total, 1190 patients were recruited and 203 (17.1 %) were randomized according to the study protocol (TPBS 104 and DGW 99). PEP developed in 14/104 patients (13.5 %) in the TPBS group and 16/99 patients (16.2 %) in the DGW group (P = 0.69). No difference existed in PEP severity between the groups. The rate of successful deep biliary cannulation was significantly higher with TPBS (84.6 % [88/104]) than with DGW (69.7 % [69/99]; P = 0.01). CONCLUSIONS: In difficult biliary cannulation, there was no difference in PEP rate between TPBS and DGW techniques. TPBS is a good alternative in cases of difficult cannulation when the guidewire is in the pancreatic duct.

Macroscopic appearance of the major duodenal papilla influences bile duct cannulation: a prospective multicenter study by the Scandinavian Association for Digestive Endoscopy Study Group for ERCP.

BACKGROUND AND AIMS: Certain appearances of the major duodenal papilla have been claimed to make cannulation more difficult during ERCP. This study uses a validated classification of the endoscopic appearance of the major duodenal papilla to determine if certain types of papilla predispose to difficult cannulation. METHODS: Patients with a naïve papilla scheduled for ERCP were included. The papilla was classified into 1 of 4 papilla types before cannulation started. Time to successful bile duct cannulation, attempts, and number of pancreatic duct passages were recorded. Difficult cannulation was defined as after 5 minutes, 5 attempts, or 2 pancreatic guidewire passages. RESULTS: A total of 1401 patients were included from 9 different centers in the Nordic countries. The overall frequency of difficult cannulation was 42% (95% confidence interval [CI], 39%-44%). Type 2 small papilla (52%; 95% CI, 45%-59%) and type 3 protruding or pendulous papilla (48%; 95% CI, 42%-53%) were more frequently difficult to cannulate compared with type 1 regular papilla (36%; 95% CI, 33%-40%; both P < .001). If an inexperienced endoscopist started cannulation, the frequency of failed cannulation increased from 1.9% to 6.3% (P < .0001), even though they were replaced by a senior endoscopist after 5 minutes. CONCLUSIONS: The endoscopic appearance of the major duodenal papilla influences bile duct cannulation. Small type 2 and protruding or pendulous type 3 papillae are more frequently difficult to cannulate. In addition, cannulation might even fail more frequently if a beginner starts cannulation. These findings should be taken into consideration when performing studies regarding bile duct cannulation and in training future generations of endoscopists.

Does long-term profound inhibition of gastric acid secretion increase the risk of ECL cell-derived tumors in man?

OBJECTIVE: Since the description of ECL cell-derived tumors in rodents after long-term profound acid inhibition inducing hypergastrinemia, there has been concern that proton pump inhibitors (PPIs) could also do that in man. The recent description of a Spanish family with gastric ECL cell tumors at the age of about 30 years secondary to a defect in the proton pump due to mutation in the ATP4A gene clearly shows that hypergastrinemia alone also is sufficient to induce ECL cell neoplasia in man. The present review aims to evaluate the risk of gastric neoplasia secondary to gastric acid inhibition. METHODS: Literature (MEDLINE) was searched for the role of the ECL cell in gastric carcinogenesis in animals and man in general and particularly secondary to long-term inhibition of acid secretion. RESULTS: An important proportion of patients treated with PPI develops hypergastrinemia causing ECL cell hyperplasia and the first descriptions of ECL cell carcinoids secondary to PPI have been reported. The role of the ECL cell has hitherto been under estimated in gastric carcinogenesis in man where for instance the signet ring cell type of gastric carcinoma seems to originate from the ECL cell. CONCLUSIONS: The first two of three steps in rodent ECL cell carcinogenesis (hyperplasia, carcinoid, and carcinoma) secondary to PPI dosing, have been described for man. It is every reason to believe that the final step, gastric carcinoma, will develop also in man. Clinical decisions should be based not only on so-called evidence based medicine, but also on physiological knowledge and animal studies.

Follow-up of patients with ECL cell-derived tumours.

OBJECTIVES: To review the presentation, treatment and outcome of patients with type 1 gastric carcinoid tumours. MATERIAL AND METHODS: We retrospectively reviewed medical records and re-evaluated histopathological specimens of 26 patients with type 1 gastric carcinoids treated at a single tertiary referral centre from 1993 to 2013, with median time of follow-up 52.5 months (IQR 90.8). RESULTS: Seven patients (27%) had single tumours and 19 patients (73%) multiple tumours at the time of diagnosis. The median number of tumours and median diameter of largest tumour were 2.5 (IQR 3.2) and 6.0 mm (IQR 9.5) respectively. Median serum gastrin was 321.0 pmol/l (IQR 604.0) and median serum chromogranin A 7.7 nmol/l (IQR 5.3). Three patients had metastatic disease at the time of diagnosis and two developed metastases during follow-up. Patients with metastatic disease had larger primary tumours than the others (20.0 mm (IQR 28.5) vs. 5.0 mm (IQR 5.5), p = 0.04). There was a positive correlation between age and tumour size (r = 0.44, p = 0.03) and between serum chromogranin A and serum gastrin at diagnosis (r = 0.76, p = 0.001). Patients were either treated with surgery (n = 8 (31%)), a long-acting somatostatin analogue and/or gastrin receptor antagonist (n = 10 (39%)) for a period of time, or were observed without treatment (n = 8 (31%) with close endoscopic follow up. CONCLUSIONS: Although gastric carcinoids have an overall good prognosis, a significant proportion develops metastatic disease. As partial and total gastrectomy is associated with major side effects, treatment with long-acting a somatostatin analogue or gastrin antagonist should be considered.

Fecal calprotectin in patients with suspected small bowel disease--a selection tool for small bowel capsule endoscopy?

OBJECTIVE: Fecal calprotectin (FC) has been proposed as a selection tool for gastrointestinal examinations, but the use of FC in the diagnosis of small bowel disease in particular is less studied. The aim of this study was to assess if FC could be used to predict findings on small bowel capsule endoscopy (SBCE). MATERIAL AND METHODS: We retrospectively collected FC values, SBCE findings and clinical data in 161 patients with suspected small bowel disease referred for SBCE. Findings on SBCE were correlated with FC levels and the diagnostic value of FC was assessed. RESULTS: Of the 161 patients, 37.3% had a positive FC and 29.8% had a finding on SBCE. Overall there was a significant difference in FC values between patients with any finding on SBCE and patients with a normal SBCE, but patients with ulcers/erosions was the only subgroup of patients with FC values significantly higher than patients with a normal SBCE. The proportion of patients with findings on SBCE increased with increasing FC value. A positive FC (≥50 mg/kg) had a sensitivity, specificity, positive predictive value and negative predictive value of 54.2%, 69.9%, 43.3% and 78.2%, respectively, for predicting findings on SBCE. CONCLUSIONS: FC alone cannot be used as a selection tool for SBCE in patients with suspected small bowel disease in a specialist setting. However, a high FC value implies a higher probability of finding significant pathology on SBCE, and thus strengthens the indication for performing the examination.

The PAS positive material in gastric cancer cells of signet ring type is not mucin.

PURPOSE: The purpose of this study is to assess the exocrine and neuroendocrine properties of tumour cells in diffuse gastric cancer with signet ring cell differentiation. MATERIAL AND METHODS: Mucin mRNA and protein expressions (MUC1, 2, 3, 4, 5AC, 6 and MUC13) were assessed by immunohistochemistry and in situ hybridization. The neuroendocrine properties were evaluated by protein and mRNA expression of the general neuroendocrine markers chromogranin A and synaptophysin. RESULTS: No MUC expression was observed in signet ring tumour cells including the amorphous substance in any of the nine cases. All cases showed immunoreactivity to synaptophysin, and seven out of nine cases immunoreactivity to chromogranin A in signet ring and non-signet ring tumour cells. Chromogranin A mRNA expression was observed in tumour cells in all samples with retained mRNA. CONCLUSIONS: The lack of MUC protein and mRNA in signet ring tumour cells suggests the amorphous substance is not mucin. The lack of MUC mRNA expression in non-signet ring tumour cells questions exocrine differentiation in this tumour group. The abundant protein expression of the general neuroendocrine markers CgA and synaptophysin, and mRNA expression in tumour cells strengthens the hypothesis that this tumour group may be of neuroendocrine origin.

Gaps between needs of patient and public involvement and interests of researchers on pancreatic cancer.

OBJECTIVE: Identify whether there were gaps between needs of end-users and interests of researchers focusing on pancreatic cancer. METHODS: A questionnaire for end-users (patients, close family, others) and researchers was developed to measure value from the perspective of different stakeholder groups. Two separate literature analyses were conducted to assess the prevalence and impact of patient and public involvement (PPI). RESULTS: Significant gaps were found between end-users and researchers in valuing basic research (15 vs 25 points, p = 0.005) and treatment (36 vs. 26 points, p = 0.015), but not in early diagnosis, risk factors, or quality of life. PPI was absent from the top 100 cited publications on pancreatic cancer research and was featured in 0.1% of all studies within the field. CONCLUSIONS: Gaps existed between needs of end-users and interests of researchers on basic research and treatment. PPI constituted an insignificant part of the overall pancreatic cancer research literature and had negligible impact in terms of citations. PRACTICAL IMPLICATIONS: To help close the gaps, PPI should be incorporated throughout the research process. The impact of PPI can be enhanced by prestigious journals in consideration of journal policies and encouragements and by dissemination at academic conferences.

The gastrin receptor antagonist netazepide (YF476) prevents oxyntic mucosal inflammation induced by Helicobacter pylori infection in Mongolian gerbils.

OBJECTIVE: Long-term Helicobacter pylori infection causes gastritis leading to hypergastrinemia and predisposes to gastric cancer. Our aim was to assess the role of gastrin in oxyntic mucosal inflammation in H. pylori-infected Mongolian gerbils by means of the gastrin receptor antagonist netazepide (YF476). DESIGN: We studied 60 gerbils for 18 months and left five animals uninfected (control group), inoculated 55 with H. pylori, and treated 28 of the infected animals with netazepide (Hp+YF476 group). Twenty-seven infected animals were given no treatment (Hp group). We measured plasma gastrin and intraluminal pH. H. pylori detection and histologic evaluations of the stomach were carried out. RESULTS: All 55 inoculated animals were H. pylori positive at termination. Eighteen animals in the Hp group had gastritis. There was a threefold increase in mucosal thickness in the Hp group compared to the Hp+YF476 group, and a threefold increase in oxyntic neuroendocrine cells in the Hp group compared to the Hp+YF476 group (p < .05). All animals in the Hp+YF476 group had macro- and microscopically normal findings in the stomach. Plasma gastrin was higher in the Hp group than in the control group (172 ± 16 pmol/L vs 124 ± 5 pmol/L, p < .05) and highest in the Hp+YF476 group (530 ± 36 pmol/L). Intraluminal pH was higher in the Hp group than in the Hp+YF476 group (2.51 vs 2.30, p < .05). CONCLUSION: The gastrin antagonist netazepide prevents H. pylori-induced gastritis in Mongolian gerbils. Thus, gastrin has a key role in the inflammatory reaction of the gastric mucosa to H. pylori infection in this species.

Gastric neuroendocrine carcinoma after long-term use of proton pump inhibitor.

We present a case of a gastric neuroendocrine carcinoma in a patient with a history of long-term proton pump inhibitor (PPI) use. A 49-year-old man using PPI for the last 15 years due to gastroesophageal reflux disease developed progressive dysphagia, dyspepsia and weight loss. Upper gastrointestinal endoscopy, endoscopic ultrasonography and abdominal CT diagnosed a malignant tumor localized to a hiatal hernia. Fasting serum chromogranin A and gastrin concentrations were elevated (32 nmol/l and 159 pmol/l, respectively). Helicobacter pylori PCR analysis of antral biopsies was negative. Biopsies from endoscopically normal oxyntic mucosa showed enterochromaffin-like (ECL) cell hyperplasia. Tumor biopsies revealed a poorly differentiated neuroendocrine carcinoma. Sevier-Munger staining, immunohistochemistry and electron microscopy indicated ECL cell as origin of the tumor cells. Concerns have previously been raised about the safety of long-term PPI use due to a possible increased risk of cancer. This case illustrates a patient with a poorly differentiated neuroendocrine carcinoma with ECL cell characteristics probably induced by hypergastrinemia secondary to long-term PPI use.

Genetic Rescue of the Highly Inbred Norwegian Lundehund.

Augmenting the genetic diversity of small, inbred populations by the introduction of new individuals is often termed "genetic rescue". An example is the Norwegian Lundehund, a small spitz dog with inbreeding-related health problems that is being crossed with three Nordic breeds, including the Norwegian Buhund. Conservation breeding decisions for the (typically) small number of outcrossed individuals are vital for managing the rescue process, and we genotyped the Lundehund (n = 12), the Buhund (n = 12), their crosses (F1, n = 7) and first-generation backcrosses to the Lundehund (F2, n = 12) with >170,000 single nucleotide polymorphism loci to compare their levels of genetic diversity. We predicted that genome-wide diversity in F2 dogs would be higher than in the Lundehund but lower than in the F1 and the Buhund, and the heterozygosity values showed the expected patterns. We also found that runs of homozygosity, extended chromosomal regions of homozygous genotypes inherited from a common ancestor, were reduced in F2 individuals compared with Lundehund individuals. Our analyses demonstrate the benefits of outcrossing but indicate that some of the acquired genetic diversity is lost following immediate backcrossing. Additional breeding among F2 crosses could therefore merit from further consideration in genetic rescue management.

Animal models to study the role of long-term hypergastrinemia in gastric carcinogenesis.

Patients with chronic hypergastrinemia due to chronic atrophic gastritis or gastrinomas have an increased risk of developing gastric malignancy, and it has been questioned whether also patients with hypergastrinemia caused by long-term use of acid inhibiting drugs are at risk. Gastric carcinogenesis in humans is affected by numerous factors and progresses slowly over years. When using animal models with the possibility of intervention, a complex process can be dissected by studying the role of hypergastrinemia in carcinogenesis within a relatively short period of time. We have reviewed findings from relevant models where gastric changes in animal models of long-term hypergastrinemia have been investigated. In all species where long-term hypergastrinemia has been induced, there is an increased risk of gastric malignancy. There is evidence that hypergastrinemia is a common causative factor in carcinogenesis in the oxyntic mucosa, while other cofactors may vary in the different models.

[Eosinophilic gastroenteritis]. / Eosinofil gastroenteritt.

BACKGROUND: Eosinophilic gastroenteritis is a disease that presents with nonspecific symptoms such as abdominal pain, nausea and diarrhoea. We here present an overview of the disease with an emphasis on practical management. MATERIAL AND METHODS: The basis for the review is literature retrieved through a search in PubMed and on our own experience treating patients with this disease. A case is reported. RESULTS: Eosinophilic gastroenteritis is a rare chronic inflammatory disease of the gastrointestinal tract that mainly affects the stomach and upper small bowel. Young middle-aged adults (most men) are most frequently affected. Abdominal pain and diarrhoea are the most common symptoms. The etiology and pathogenesis is unknown. Correct diagnosis may be difficult and is based on gastrointestinal symptoms, eosinophilic infiltration of the bowel wall and exclusion of other causes of eosinophilia. Treatment is symptomatic with different doses of corticosteroids. Long-term prognosis seems good. INTERPRETATION: The clinical presentation of eosinophilic gastroenteritis varies and underdiagnosing is therefore likely. Many patients have normal levels of eosinophils in blood and normal findings with endoscopy. Correct diagnosis therefore depends on awareness of the disease.

Gastric Cancers Missed at Upper Endoscopy in Central Norway 2007 to 2016-A Population-Based Study.

BACKGROUND: The rates of missed gastric cancers (MGC) at upper endoscopy (UE) has been reported at 5-10% in Western countries. We aimed to calculate the rate of MGC and identify factors associated with MGC. METHODS: Retrospective population-based cohort study including 730 patients diagnosed with gastric adenocarcinoma in Central Norway 2007-2016. MGCs were incident gastric adenocarcinomas diagnosed 6-36 months after a previous UE. Factors associated with MGC were examined. Definitely missed (UE 6-12 months prior) and potentially missed (UE 12-36 months prior) MGCs were compared. RESULTS: Sixty-seven (9.2%) of 730 gastric cancers were MGC. MGC were associated with localization (p = 0.009) and more frequent in the corpus, Lauren's histological type (p = 0.028) and diffuse type more prevalent, and previous Billroth 2-operation (14.9% vs. 4.7%, p = 0.001). MGCs were diagnosed at earlier stages (p = 0.037). An ulceration was more common in patients with definitely missed than potentially MGC (40.9% vs. 17.8%, p = 0.041). CONCLUSIONS: MGC accounted for 9.2% of gastric cancers in Central Norway. MGC were associated with localization in the corpus, Lauren´s diffuse type and previous Billroth-2-operation. Intensified follow-up and adequate biopsy sampling of patients with gastric ulcerations could reduce the rate of missed gastric cancers.

Rebound acid hypersecretion from a physiological, pathophysiological and clinical viewpoint.

OBJECTIVE: The recent description of dyspepsia in healthy individuals after stopping treatment with proton-pump inhibitors (PPIs) indicates that reflux disease may worsen due to this treatment. The aim of this paper is to review current knowledge of the regulation of gastric acid secretion, including maximal acid secretion, and to improve understanding of the pathogenesis of acid-related conditions. MATERIAL AND METHODS: We reviewed our findings from three decades of studies on gastric acid secretion in the isolated rat stomach and in humans as well as studies by the group of Robert Jensen involving gastrinoma patients. RESULTS: The parietal cell has receptors for histamine and acetylcholine, whereas the gastrin receptor is localized to the enterochromaffin-like (ECL) cell. Gastrin-stimulated histamine release depends on the ECL cell mass, which is regulated by gastrin. The parietal cell mass is also influenced by gastrin. All conditions with hypergastrinemia concomitant with a normal oxyntic mucosa result in an increase in acid secretion. Helicobacter pylori infection in the antral mucosa may induce duodenal ulcers by its effect on acid secretion, as in patients with gastrinoma. Whereas PPIs induce clinically important rebound acid hypersecretion, histamine-2 blockers do not, since they also induce tolerance. CONCLUSION: From a biological and physiological point of view, patients should be given treatment that disturbs the normal physiology as little as possible.

Gastric cancer: animal studies on the risk of hypoacidity and hypergastrinemia.

Gastric hypoacidity and hypergastrinaemia are seen in several conditions associated with an increased risk of gastric malignancy. Hypoacidity and hypergastrinaemia are closely related and their long-term effects are difficult to study separately in patients. Studies using animal models can provide valuable information about risk factors and mechanisms in gastric cancer development as the models allow a high degree of intervention when introducing or eliminating factors possibly affecting carcinogenesis. In this report, we briefly review findings from relevant animal studies on this topic. Animal models of gastric hypoacidity and hypergastrinaemia provide evidence hypergastrinaemia is a common causative factor in many otherwise diverse settings. In all species where sufficient hypoacidity and hypergastrinaemia have been induced, a proportion of the animals develop malignant lesions in the gastric oxyntic mucosa.

[Whipple's disease]. / Whipples sykdom.

BACKGROUND: Whipple's disease is a rare infectious disease. This review describes the clinical picture, diagnostic aspects and treatment options. MATERIAL AND METHODS: Based on a clinical case, a literature study was performed by searching PubMed (unlimited) with the words "whipples disease" combined with " TROPHERYMA WHIPPELII: " (118 hits) and " TROPHERYMA WHIPPLEI:" (65 hits). Titles and abstracts were used to identify other relevant articles. RESULTS AND INTERPRETATION: Whipple's disease may affect several organ systems and thus causes a wide range of symptoms. The most common ones are weight loss, abdominal pain, diarrhoea and arthralgia. The diagnosis is based on PAS-POSITIVE MATERIAL: in duodenal biopsies and identification of gene fragments from the bacterium TROPHERYMA WHIPPLEI:. Presence of the bacterium may be confirmed by sensitive polymerase chain reaction assays. Left without treatment the disease may be lethal. Proper antibiotic treatment is imperative to heal the disease.

Expression of erythropoietin and neuroendocrine markers in clear cell renal cell carcinoma.

The aim of the study was to investigate the expression of erythropoietin and neuroendocrine markers in clear cell renal cell carcinoma (CCRCC). We retrospectively reviewed the medical records and re-evaluated histopathological specimens of 33 patients with CCRCC and compared with those of 11 cases of non-CCRCC. All patients were treated with a partial or radical nephrectomy at St. Olavs Hospital, Trondheim University Hospital, between 2010 and 2016. Thirty-three patients who were diagnosed with CCRCC had a total of 35 tumours, where 34 of the tumours were CCRCC and one was papillary adenoma. Thirty-three (97%) of 34 CCRCCs were positive for erythropoietin, and the same 33 (97%) tumours demonstrated strong expression for neuron-specific enolase (NSE). Two (6%) of 34 CCRCCs had a positive reaction for synaptophysin, and three (9%) of 34 were positive for CD56. Erythropoietin and NSE were negative in non-CCRCCs, and chromogranin A was negative in all tumours. The above findings suggest that there is a strong association between CCRCC and the expression of erythropoietin and NSE.

The cytoprotective protein clusterin is overexpressed in hypergastrinemic rodent models of oxyntic preneoplasia and promotes gastric cancer cell survival.

The cytoprotective protein clusterin is often dysregulated during tumorigenesis, and in the stomach, upregulation of clusterin marks emergence of the oxyntic atrophy (loss of acid-producing parietal cells)-associated spasmolytic polypeptide-expressing metaplasia (SPEM). The hormone gastrin is important for normal function and maturation of the gastric oxyntic mucosa and hypergastrinemia might be involved in gastric carcinogenesis. Gastrin induces expression of clusterin in adenocarcinoma cells. In the present study, we examined the expression patterns and gastrin-mediated regulation of clusterin in gastric tissue from: humans; rats treated with proton pump (H+/K+-ATPase) inhibitors and/or a gastrin receptor (CCK2R) antagonist; H+/K+-ATPase ß-subunit knockout (H/K-ß KO) mice; and Mongolian gerbils infected with Helicobacter pylori and given a CCK2R antagonist. Biological function of secretory clusterin was studied in human gastric cancer cells. Clusterin was highly expressed in neuroendocrine cells in normal oxyntic mucosa of humans and rodents. In response to hypergastrinemia, expression of clusterin increased significantly and its localization shifted to basal groups of proliferative cells in the mucous neck cell-chief cell lineage in all animal models. That shift was partially inhibited by antagonizing the CCK2R in rats and gerbils. The oxyntic mucosa of H/K-ß KO mice contained areas with clusterin-positive mucous cells resembling SPEM. In gastric adenocarcinomas, clusterin mRNA expression was higher in diffuse tumors containing signet ring cells compared with diffuse tumors without signet ring cells, and clusterin seemed to be secreted by tumor cells. In gastric cancer cell lines, gastrin increased secretion of clusterin, and both gastrin and secretory clusterin promoted survival after starvation- and chemotherapy-induced stress. Overall, our results indicate that clusterin is overexpressed in hypergastrinemic rodent models of oxyntic preneoplasia and stimulates gastric cancer cell survival.