Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS): a new autosomal dominant syndrome

Pediatric gastric adenocarcinoma: A National Cancer Data Base review

PURPOSE

We sought to compare the presentation, management, and outcomes in gastric adenocarcinoma cancer for pediatric and adult patients.

METHODS

Using the 2004 to 2014 National Cancer Database (NCDB), patients ≤21 years (pediatric) were retrospectively compared to >21 years (adult). Chi-squared tests were used to compare categorical variables, and Cox regression was used to estimate hazard ratios (HR) for survival differences.

RESULTS

Of the 129,024 gastric adenocarcinoma cases identified, 129 (0.10%) occurred in pediatric patients. Pediatric cases presented with more advanced disease, including poorly differentiated tumors (81% vs 65%, p = 0.006) and stage 4 disease (56% vs 41%, p = 0.002). Signet ring adenocarcinoma comprised 45% of cases in the pediatric group as compared to 20% of cases in the adults (P < 0.001). Similar proportions in both groups underwent surgery. However, near-total gastrectomy was more common in the pediatric group (16% vs 6%, p < 0.001). The proportions of patients with negative margins, nodal examination, and presence of positive nodes were similar. There was no overall survival difference between the two age groups (HR 0.92, 95% Confidence interval 0.73-1.15).

CONCLUSION

While gastric adenocarcinoma in pediatric patients present with a more advanced stage and poorly differentiated tumors compared to adults, survival appears to be comparable.

TYPE OF STUDY

Retrospective cohort study.

LEVEL OF EVIDENCE

III.

Hereditary Colorectal Cancer Syndromes

OBJECTIVES

To review the most common hereditary colorectal cancer syndromes with known associated mutated genes, associated cancer risks, and current screening and prevention current.

DATA SOURCES

Online search of PubMed, EBSCOhost, and Medline, review of the literature for each syndrome described.

CONCLUSION

Hereditary colon cancer accounts for approximately 10% of all colorectal cancers in the United States. There are multiple hereditary colorectal cancer syndromes known with respective associated genetic mutations, cancer risks, and screening and prevention recommendations.

IMPLICATIONS FOR NURSING PRACTICE

Nurses at all levels of practice need to be knowledgeable about the various hereditary colorectal cancer syndromes to guide appropriate referral to a genetics professional and to provide appropriate care to these high-risk individuals.

Helicobacter pylori Infection, the Gastric Microbiome and Gastric Cancer

After a long period during which the stomach was considered as an organ where microorganisms could not thrive, Helicobacter pylori was isolated in vitro from gastric biopsies, revolutionising the fields of Microbiology and Gastroenterology. Since then, and with the introduction of high-throughput sequencing technologies that allowed deep characterization of microbial communities, a growing body of knowledge has shown that the stomach contains a diverse microbial community, which is different from that of the oral cavity and of the intestine. Gastric cancer is a heterogeneous disease that is the end result of a cascade of events arising in a small fraction of patients colonized with H. pylori. In addition to H. pylori infection and to multiple host and environmental factors that influence disease development, alterations to the composition and function of the normal gastric microbiome, also known as dysbiosis, may also contribute to malignancy. Chronic inflammation of the mucosa in response to H. pylori may alter the gastric environment, paving the way to the growth of a dysbiotic gastric bacterial community. This dysbiotic microbiome may promote the development of gastric cancer by sustaining inflammation and/or inducing genotoxicity. This chapter summarizes what is known about the gastric microbiome in the context of H. pylori-associated gastric cancer, introducing the emerging dimension of the microbiome into the pathogenesis of this highly incident and deadly disease.

CDH1 Gene and Hereditary Diffuse Gastric Cancer Syndrome: Molecular and Histological Alterations and Implications for Diagnosis And Treatment

Gastric cancer, a group of common malignancies, results in the most cancer mortality worldwide after only lung and colorectal cancer. Although familial gastric cancers have long been recognized, it was not until recently that they were discovered to be associated with mutations of specific genes. Mutations of CDH1, the gene encoding E-cadherin, are the most common germline mutations detected in gastric cancer and underlie hereditary diffuse gastric cancer (HDGC) syndrome. All reported HDGCs are the pure diffuse type by Lauren classification and are associated with dismal prognosis once the tumor invades the submucosa. Because CDH1 germline mutations are inherited in an autosomal-dominant fashion and have high penetrance, the International Gastric Cancer Linkage Consortium (IGCLC) developed criteria to facilitate the screening of CDH1 mutation carriers; these criteria have been proven to have excellent sensitivity and specificity. Recent histologic studies suggest that HDGC progresses through several stages. Even when the tumor becomes "invasive" in lamina propria, it may stay indolent for a long time. However, the molecular mechanisms that induce the transitions between stages and determine the length of the indolent phase remain to be determined. Although the standard management for CDH1 mutation carriers is prophylactic total gastrectomy, many questions must be answered before the surgery can be done. These include the optimal surveillance strategy, the best strategy to choose surgical candidates, and the ideal time to perform surgery. In addition to increasing the risk of gastric cancer, CDH1 germline mutations also increase the risk of invasive lobular carcinoma of the breast, and possibly colorectal adenocarcinoma, and are associated with blepharocheilodontic syndrome (a congenital development disorder). However, the optimal management of these conditions is less established owing to insufficient data regarding the risk of cancer development. This review focuses on molecular and histological findings in HDGC, as opposed to sporadic diffuse gastric cancer, and their implications for the management of CDH1 mutation carriers and the diagnosis and treatment of HDGC. Other conditions associated with CDH1 germline mutations and future research directions are also discussed.

Gastric adenocarcinoma and proximal polyposis of the stomach: diagnosis and clinical perspectives

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is a recently described, rare gastric polyposis syndrome. It is characterized by extensive involvement of the fundus and body of the stomach with fundic gland polyps sparing the antrum and lesser curvature, an autosomal dominant inheritance pattern with incomplete penetrance, and a significant predisposition for the development of gastric adenocarcinoma. Due to the recent discovery of APC promotor IB mutations (c.-191T>C, c.-192A>G, and c.-195A>C), which reduce binding of the transcription factor Yin Yang 1 (YY1) and transcriptional activity of the promotor, as its underlying genetic perturbation, GAPPS has been added to the growing molecular class of APC-associated disorders. Recent reports on family members afflicted by gastric polyposis due to GAPPS have described the development of metastatic cancer or the presence of invasive gastric adenocarcinoma in total gastrectomy specimens after variable periods of endoscopic surveillance emphasizing the need for an improved understanding of the to-date poorly characterized natural history of the syndrome. There are, however, currently no guidelines on screening, timing of prophylactic gastrectomy, or endoscopic surveillance for GAPPS available. In this review, we summarize the clinical, pathological, and genetic aspects of GAPPS as well as management approaches to this rare cancer predisposition syndrome, highlighting the need for early recognition, a multidisciplinary approach, and the creation of prospective family registries and consensus guidelines in the near future.

Resolving gastric cancer aetiology: an update in genetic predisposition

Every year gastric cancer accounts for nearly 1 million new cases and more than 720 000 deaths worldwide. Prognosis is dismal because most patients are diagnosed with advanced disease; as such, gastric cancer outcomes will benefit from better methods for identification of at-risk individuals that can be targeted for early detection. One approach to targeting high-risk populations is to identify individuals who are genetically predisposed to gastric cancer, as up to 15% of all patients report family history of the disease. On the basis of clinical manifestations, three gastric cancer syndromes have been described, but the diagnosis of some of these syndromes is suboptimal and could benefit from genetic information. Over the past decade, genome-wide association and next-generation sequencing studies have identified several low penetrance variants and high-risk genes, considerably increasing our understanding of inherited gastric cancer predisposition. From these studies, PALB2 has emerged as a new familial gastric cancer gene. Furthermore, genetic analyses in patients with sporadic gastric cancer suggest that more than 10% of all cases have pathogenic mutations, a finding of great importance for cancer aetiology. In this Review, we summarise the role of genetics in gastric cancer aetiology and the implications of genetics findings for the prevention of this malignancy.

First report of an Asian family with gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) revealed with the germline mutation of the APC exon 1B promoter region

A 48-year-old Japanese female with left hypochondralgia presented at our hospital. Esophagogastroduodenoscopy (EGD) revealed gastric cancers and carpeting fundic gland polyposis (FGPs) without Helicobacter pylori infection. Computed tomography showed multiple liver metastases. Total colonoscopy revealed a colonic tubular adenoma but not polyposis. She was diagnosed as having advanced gastric cancer with liver metastasis and received chemotherapy. Her mother had died from gastric cancer, and her elderly brother and niece had FGPs as revealed by EGD. Thus, the pedigree was diagnosed as gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). Germline mutation analysis exhibited a point mutation in exon1B of the APC gene (c.-191T > C). Adenocarcinoma showed a gastric mucinous phenotype and was positive for a somatic mutation of p53, suggesting that p53 mutation may play a role in FGPs carcinogenesis. This is the first family with GAPPS in Asia in whom germline mutation of APC exon 1B has been detected.

Screening and surveillance in hereditary gastrointestinal cancers: Recommendations from the European Society of Digestive Oncology (ESDO) expert discussion at the 20th European Society for Medical Oncology (ESMO)/World Congress on Gastrointestinal Cancer, Barcelona, June 2018

Patients with hereditary gastrointestinal (GI) cancers represent a substantial fraction of the overall affected population. Although awareness for hereditary GI cancer syndromes is on the rise, identification of patients and measures of surveillance are often unclear in everyday clinical routine. Therefore, the European Society of Digestive Oncology expert discussion 2018 at the World Congress on Gastrointestinal Cancer focussed on screening and surveillance of hereditary colorectal, gastric and pancreatic cancers. An international panel of experts and opinion leaders developed the here presented recommendations based on published evidence and on profound clinical expertise to facilitate clinical routine in identification and caretaking of patients with familial GI cancers.

FANCA D1359Y mutation in a patient with gastric polyposis and cancer susceptibility: A case report and review of literature

Gastric polyposis is a rare disease. Not all polyps progress to cancer. Monoallelic mutation in Fanconi anemia (FA) genes, unlike biallelic gene mutations that causes typical FA phenotype, can increase risks of cancers in a sporadic manner. Aberrations in the FA pathway were reported in all molecular subtypes of gastric cancer. We studied a patient with synchronous gastric cancer from gastric polyposis by conducting a 13-year long-term follow up. Via pathway-driven massive parallel genomic sequencing, a germline mutation at FANCA D1359Y was identified. We identified several recurrent mutations in DNA methylation (TET1, V873I), the β-catenin pathway (CTNNB1, S45F) and RHO signaling pathway (PLEKHG5, R203C) by comparing the genetic events between benign and malignant gastric polyps. Furthermore, we revealed gastric polyposis susceptible genes and genetic events promoting malignant transformation using pathway-driven targeted gene sequencing.

Gastric cancer: French intergroup clinical practice guidelines for diagnosis, treatments and follow-up (SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO)

INTRODUCTION

This document is a summary of the French Intergroup guidelines regarding the management of gastric cancer published in October 2016, available on the website of the French Society of Gastroenterology (SNFGE) (www.tncd.org), updated in October 2017.

METHODS

This collaborative work was realized under the auspices of several French medical societies involved in management of gastric cancer. Recommendations are graded in three categories (A-C), according to the amount of evidence found in the literature until July 2017.

RESULTS

There are several known risk factors for gastric cancer, including Helicobacter pylori and genetic predispositions, both requiring a specific screening for patients and their relatives. The diagnosis and staging evaluation are essentially based on gastroscopy plus biopsies and computed tomography scan. The endoscopic ultrasonography can be used for superficial tumors in case of discussion for endoscopic resection (T1N0). For local disease (N+ and/or T > T1), the strategic therapy is based on surgery associated with perioperative chemotherapy. In the absence of preoperative treatment (for any raison), the postoperative chemoradiotherapy (or chemotherapy) should be discussed for patients with stage II or III tumor. For metastatic disease, the treatment is based on "palliative" chemotherapy consisting in a doublet or triplet regimens depending of age, performance status and HER2 tumor status. For patients with limited metastatic disease, surgical resection could be discussed in multidisciplinary meeting in case of stable disease after chemotherapy.

CONCLUSION

These guidelines in gastric cancer are done to help decision for daily clinical practice. These recommendations are permanently being reviewed. Each individual case must be discussed within a multidisciplinary team.

Variables affecting penetrance of gastric and duodenal phenotype in familial adenomatous polyposis patients

BACKGROUND

Patients with familial adenomatous polyposis (FAP) frequently undergo colectomy to reduce the 70 to 90% lifetime risk of colorectal cancer. After risk-reducing colectomy, duodenal cancer and complications from duodenal surgeries are the main cause of morbidity. Our objective was to prospectively describe the duodenal and gastric polyp phenotype in a cohort of 150 FAP patients undergoing pre-screening for a chemoprevention trial and analyze variables that may affect recommendations for surveillance.

METHODS

Individuals with a diagnosis of FAP underwent prospective esophagogastroduodenoscopy using a uniform system of mapping of size and number of duodenal polyps for a 10 cm segment. Gastric polyps were recorded as the total number.

RESULTS

The distribution of the count and sum diameter of duodenal polyps were statistically different in two genotype groups, those with APC mutations associated with classic FAP had a greater count (median 17) and sum diameter of polyps (median 32 mm) than those with APC mutations associated with attenuated FAP (median count 4 and median sum diameter of 7 mm) (p < 0.0001). The number of gastric polyps did not differ based on genotype (p = 0.67) but advancing age correlated with severity of gastric polyposis (p = 0.019). Spigelman (modified) staging of II or greater was found in 88% of classic FAP patients and 48% attenuated FAP patients. Examples of severe and mild upper GI phenotype are observed in patients with identical APC mutations, showing that the APC mutation location is not absolutely predictive of an upper GI phenotype.

CONCLUSIONS

Most FAP patients have duodenal and gastric polyps which become more prevalent and advanced with age. Standard upper endoscopic surveillance is recommended based on personal history independent of APC mutation location.

TRIAL REGISTRATION

NCT 01187901 registered August 24, 2010, prospective to enrollment.

Emerging Concepts in Gastric Neoplasia: Heritable Gastric Cancers and Polyposis Disorders

Hereditary gastric cancer is a relatively rare disease with specific clinical and histopathologic characteristics. Hereditary gastric cancer of the diffuse type is predominantly caused by germline mutations in CDH1. The inherited cause of familial intestinal gastric cancer is unknown. Gastric adenocarcinoma and proximal polyposis of the stomach is a hereditary cancer syndrome caused by germline mutations in promoter 1B of APC. Other well-defined cancer syndromes, such as Lynch, Li-Fraumeni, and hereditary breast or ovarian cancer syndromes, are associated with increased risk of gastric cancer. This article reviews important histopathologic features and emerging concepts regarding gastric carcinogenesis in these syndromes.

Comparison of dysplastic fundic gland polyps in patients with and without familial adenomatous polyposis

AIMS

Dysplastic fundic gland polyps (d-FGPs) typically arise in patients with familial adenomatous polyposis (FAP) but may occur in non-syndromic patients. They rarely become malignant, but their significance is unclear, especially in non-syndromic patients. We aimed to compare d-FGPs in patients with and without FAP, using clinicopathologic findings and β-catenin immunohistochemistry (IHC).

METHODS AND RESULTS

We identified 124 fundic gland polyps with low-grade dysplasia (LGD) or high-grade dysplasia (HGD) or indefinite for dysplasia (IFD) from 66 patients (27 with FAP; 39 non-syndromic). We recorded patient sex, age at first d-FGP, time until subsequent d-FGP (if any), history of non-gastric cancer (no patients had gastric cancer), proton-pump inhibitor use, and the presence of Helicobacter pylori. β-Catenin IHC was performed on cases with available blocks. The mean age at d-FGP diagnosis was 31 years for FAP patients and 61 years for non-syndromic patients (P < 0.0001). Sixteen FAP patients (59%) developed at least one subsequent d-FGP, as compared with 10 (27%) non-syndromic patients (P = 0.0099). The median time between d-FGP detection was 11.5 months in FAP patients and 7 months in non-syndromic patients (P = 0.82). Six FAP patients (22%) and 17 non-syndromic patients (44%) had non-gastric malignancies (P = 0.11). β-Catenin IHC showed nuclear positivity in 14 of 112 (13%) d-FGPs: 12 of 94 with LGD, two of three with HGD, and none of 15 with IFD polyps.

CONCLUSIONS

Familial adenomatous polyposis patients develop d-FGPs earlier and more often develop additional ones than non-syndromic patients. d-FGPs in FAP and non-syndromic patients have similar low rates of β-catenin nuclear IHC positivity. FAP and non-syndromic patients developed non-gastric cancers at similar rates, suggesting that d-FGPs may portend a general increased risk of carcinogenesis in non-syndromic patients.

Biomarker-driven targeted therapies for gastric/gastro-esophageal junction malignancies

Gastroesophageal malignancies often contain high amounts of genetic and molecular alterations that result in an aggressive disease capable of rapidly metastasizing to distant organs and early development of drug resistance. Most patients in the Western hemisphere present with locally advanced or metastatic disease that is treated with systemic chemotherapy used either in the neoadjuvant or palliative setting, respectively. This article will review the various recent advances in the development of targeted therapies for the treatment of advanced gastric and gastroesophageal cancer.

Histologic and immunohistochemical differences between hereditary and sporadic diffuse gastric carcinoma

We aimed to identify histopathologic features unique in hereditary diffuse gastric cancer (HDGC) by comparing with its sporadic counterpart (SDGC). 11 patients with confirmed CDH1 mutation who were found to have HDGC in a prophylactic total gastrectomy were collected. Median age of HDGC patients was 39 years (range 24-57). All HDGC cases had intramucosal signet ring cell carcinoma. Twenty-three invasive tumor foci from 7 patients with HDGC were available for ancillary studies, and we evaluated each focus separately. Almost all foci (20/23) showed two distinct tumor cell populations, namely, large signet ring cells and small signet ring cells. The large cells were located just beneath the surface epithelium and were positive for mucicarmine and pCEA, while the small cells were found in the deeper lamina propria and were mostly negative for mucicarmine and pCEA. A subset of small cells (6 foci from two resected stomachs) showed poorly differentiated morphology with p16 positivity. All other tumor cells with well-differentiated signet ring cell morphology were negative for p16. In contrast, 18 of 20 SDGCs were positive for p16. In addition, all HDGCs were negative for CDX2, while 19 of 20 SDGCs were positive. We propose that there are three distinct tumor cell populations in HDGC: well-differentiated large cells, well-differentiated small cells, and poorly differentiated small cells, and that the latter group with aberrant p16 expression may represents a more aggressive phenotype. The absence of CDX2 in HDGC suggests that it may develop along a carcinogenetic pathway different from that of SDGC.

The Role of the Surgical Pathologist in the Diagnosis of Gastrointestinal Polyposis Syndromes

Polyps of the gastrointestinal tract are very common lesions and most frequently sporadic in nature. Some polyp subtypes are associated with rare hereditary polyposis syndromes, including juvenile polyposis syndrome, Peutz-Jeghers syndrome, and Cowden syndrome. However, many sporadic benign lesions of the gastrointestinal tract can mimic some of these syndromic hamartomatous polyps. The role of the surgical pathologist is to raise the possibility of a hereditary condition in case of suggestive polyp histology and to look for clinical information to support the suspected diagnosis. In this review, the clinical presentation and the pathology associated with these rare hamartomatous polyposis syndromes are discussed in an attempt to provide pathologists clues in suggesting one such syndrome on the basis of histologic findings and clinical context. Identification of affected individuals is important because of the increased gastrointestinal and other malignancies. Recently, new adenomatous polyposis syndromes have been discovered, expanding the genetic causes of patient diagnosed with multiple colonic adenomas. By being aware of the clinical phenotype and the tumor spectrum associated with gastrointestinal polyposis syndromes, surgical pathologists can play a critical role in recommending genetic counseling when suspicious of such a diagnosis. This may lead to the identification of a genetic cause and appropriate surveillance of affected family members to screen for associated malignancies.

Neoplastic Lesions of Gastric Adenocarcinoma and Proximal Polyposis Syndrome (GAPPS) Are Gastric Phenotype

Neoplastic lesions of gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) are gastric phenotype. GAPPS was reported in 2011 as a new autosomal dominant gastric polyposis syndrome characterized by involvement of the gastric body/fundus with sparing of the antrum by multiple polyps, reported to be primarily fundic gland polyps (FGPs), with progression to dysplasia and adenocarcinoma of intestinal type. Our series consists of 51 endoscopic biopsies and 5 gastrectomy specimens from 25 patients belonging to a previously defined GAPPS family. Slides were reviewed and further stains performed. Endoscopy was abnormal in 15 of the 25 patients: carpeting polyposis of the gastric body and fundus in 14 and a gastric mass without polyposis in one. The most common polypoid lesion (seen in 12 patients) was a disorganized proliferation of specialized/oxyntic glands high up in the mucosa involving the attenuated foveolar region around the gastric pits, which we have termed "hyperproliferative aberrant pits". Well developed FGP were seen in 10 patients. Established neoplastic lesions seen in 9 patients were: (1) discrete gastric adenomas, (2) multifocal "flat" dysplasia in the setting of hyperproliferative aberrant pits +/- FGPs, (3) adenomatous tissue associated with adenocarcinoma. All cases of dysplasia were of gastric phenotype based on morphology and mucin immunohistochemistry.

IN CONCLUSION

(1) the spectrum of gastric pathology associated with GAPPS is wider than previously reported, (2) the earliest microscopic clue is the finding of hyperproliferative aberrant pits, and (3) the dysplasia is gastric phenotype and the subsequent adenocarcinoma may follow the gastric pathway of carcinogenesis.

Proton-pump inhibitors: understanding the complications and risks

Proton-pump inhibitors (PPIs) are the most effective therapy for the full spectrum of gastric-acid-related diseases. However, in the past decade, a steadily increasing list of complications following long-term use of PPIs has been reported. Their potent acid-suppressive action induces several structural and functional changes within the gastric mucosa, including fundic gland polyps, enterochromaffin-like cell hyperplasia and hypergastrinaemia, which can be exaggerated in the presence of Helicobacter pylori infection. As discussed in this Review, most associations of PPIs with severe adverse events are not based on sufficient evidence because of confounding factors and a lack of plausible mechanisms. Thus, a causal relationship remains unproven in most associations, and further studies are needed. Awareness of PPI-associated risks should not lead to anxiety in patients but rather should induce the physician to consider the appropriate dosing and duration of PPI therapy, including long-term monitoring strategies in selected groups of patients because of their individual comorbidities and risk factors.

A novel APC promoter 1B deletion shows a founder effect in Italian patients with classical familial adenomatous polyposis phenotype

Familial adenomatous polyposis is a Mendelian syndrome in which germline loss-of-function mutations of APC are associated with multiple adenomatous polyps of the large bowel, a multiplicity of extracolonic features, and a high lifetime risk of colorectal cancer. Different APC germline mutations have been identified, including sequence changes, genomic rearrangements, and expression defects. Recently, very rare families have been associated with constitutive large deletions encompassing the APC-5' regulatory region, while leaving the remaining gene sequence intact; the regulatory region contains a proximal and a distal promoter, called 1A and 1B, respectively. We identified a novel deletion encompassing promoter 1B in a large Italian family that manifested polyposis in three of the six branches descending from a founding couple married in 1797. By combining different molecular approaches on both DNA and RNA, we precisely mapped this deletion (6858 bp in length) that proved to be associated with APC allele silencing. The finding of the same deletion in two additional polyposis families pointed to a founder mutation in Italy. Deletion carriers from the three families all showed a "classical" polyposis phenotype. To explore the molecular mechanisms underlying promoter deletions, we performed an in silico analysis of the breakpoints of 1A and 1B rearrangements so far reported in the literature; moreover, to decipher genotype-phenotype correlations, we critically reviewed current knowledge on deletions versus point mutations in the APC-5' regulatory region.

A Clinicopathologic Evaluation of Incidental Fundic Gland Polyps With Dysplasia: Implications for Clinical Management

OBJECTIVES

Fundic gland polyps (FGPs) can rarely exhibit dysplasia of the surface epithelium. Based on retrospective data, FGPs with dysplasia (FGPDs) are thought to be a strong marker for familial adenomatous polyposis (FAP), although sporadic, non-syndromic FGPDs also occur. Owing to the significant syndromic association, diagnosis of an apparently sporadic FGPD may prompt clinical evaluation for FAP, especially its attenuated variant. We sought to evaluate the positive predictive value of incidental FGPDs for FAP. We also characterized the clinicopathologic features of incidental FGPDs to advance clinical management.

METHODS

Incidental FGPDs were identified from 2004 to 2015 in patients without FAP at biopsy. All clinical follow-up data were reviewed, and germline analysis for APC and MUTYH mutations was performed in consenting patients.

RESULTS

We identified 25 incidental FGPDs in patients not known to have FAP (11.6% of FGPDs, 1.0% of all FGPs). Four patients had a family history of gastric polyps or gastrointestinal cancers. Clinical management included completion polypectomy and gastric endoscopic surveillance (44%), endoscopic surveillance alone (32%), no follow-up (24%), colonoscopy referral (12%), and genetic counseling (4%). Colonoscopies on record revealed 0-7 cumulative adenomas. Follow-up averaged 4.4 years (range 0.3-10.6). No clinical evidence of FAP, gastric cancer, death, or surgery occurred. None of the 11 patients consenting to germline APC and MUTYH testing had genomic alterations.

CONCLUSIONS

Incidental FGPDs in this series were all found to be sporadic (25/25) by endoscopic, clinical, and molecular findings, and thus FGPDs were not harbingers of FAP. As isolated findings, FGPDs do not appear to warrant follow-up genetic counseling or testing.

Endoscopic Management of Early Gastric Adenocarcinoma and Preinvasive Gastric Lesions

Early gastric cancer (ECG) can be difficult to diagnose endoscopically. Endoscopists should be familiar with subtle changes and endoscopic features of EGC. Chromoendoscopy and image-enhanced endoscopy improve diagnostic accuracy and facilitate endoscopic resection. Endoscopic submucosal dissection is a preferred endoscopic technique for resection of EGC and offers a comparable overall survival to surgical resection. Endoscopic management of benign gastric epithelial polyps (fundic gland polyps, hyperplastic polyps, and gastric adenoma) depends on patient symptomatology, patient's comorbidities (eg, familial syndromes), lesions' characteristics, and risk of malignant transformation. This article provides an overview of endoscopic management of EGC and common premalignant gastric lesions.

Genetics of Gastric Cancer

Gastric cancer represents a major cause of cancer mortality worldwide despite a declining incidence. New molecular classification schemes developed from genomic and molecular analyses of gastric cancer have provided a framework for understanding this heterogenous disease, and early findings suggest these classifications will be relevant for designing and implementing new targeted therapies. The success of targeted therapy and immunotherapy in breast cancer and melanoma, respectively, has not been duplicated in gastric cancer, but trastuzumab and ramucirumab have demonstrated efficacy in select populations. New markers that predict therapeutic response are needed to improve patient selection for both targeted and immunotherapies.

Historical Perspective on Familial Gastric Cancer

Gastric cancer is a common disease worldwide, typically associated with acquired chronic inflammation in the stomach, related in most instances to infection by Helicobacter pylori. A small percentage of cases occurs in familial clusters, and some of these can be linked to specific germline mutations. This article reviews the historical background to the current understanding of familial gastric cancer, focuses on the entity of hereditary diffuse gastric cancer, and also reviews the risks for gastric cancer related to a number of other familial genetic diseases.

Gastric Cancer in the Era of Precision Medicine

Gastric cancer (GC) remains the third most common cause of cancer death worldwide, with limited therapeutic strategies available. With the advent of next-generation sequencing and new preclinical model technologies, our understanding of its pathogenesis and molecular alterations continues to be revolutionized. Recently, the genomic landscape of GC has been delineated. Molecular characterization and novel therapeutic targets of each molecular subtype have been identified. At the same time, patient-derived tumor xenografts and organoids now comprise effective tools for genetic evolution studies, biomarker identification, drug screening, and preclinical evaluation of personalized medicine strategies for GC patients. These advances are making it feasible to integrate clinical, genome-based and phenotype-based diagnostic and therapeutic methods and apply them to individual GC patients in the era of precision medicine.

Molecular classification of gastric cancer

INTRODUCTION

Gastric cancer is among the most common cancers worldwide. Despite declining incidences, the prognosis remains dismal in Western countries and is better in Asian countries with national cancer screening programs. Complete endoscopic or surgical resection of the primary tumor with or without lymphadenectomy offers the only chance of cure in the early stage of the disease. Survival of more locally advanced gastric cancers was improved by the introduction of perioperative, adjuvant and palliative chemotherapy. However, the identification and usage of novel predictive and diagnostic targets is urgently needed. Areas covered: Recent comprehensive molecular profiling of gastric cancer proposed four molecular subtypes, i.e. Epstein-Barr virus-associated, microsatellite instable, chromosomal instable and genomically stable carcinomas. The new molecular classification will spur clinical trials exploring novel targeted therapeutics. This review summarizes recent advancements of the molecular classification, and based on that, putative pitfalls for the development of tissue-based companion diagnostics, i.e. prevalence of actionable targets and therapeutic efficacy, tumor heterogeneity and tumor evolution, impact of ethnicity on gastric cancer biology, and standards of care in the East and West. Expert commentary: The overall low prevalence of actionable targets and tumor heterogeneity are the two main obstacles of precision medicine for gastric cancer.

[Gastric tumors and tumor precursors]

Gastric cancer is the fifth (men) and sixth (women) most common cause of cancer-related death in Germany. Despite a declining incidence of distal gastric cancer, the prognosis remains dismal: the 5‑year survival rate ranges between 35% for women and 31% for men. The majority are adenocarcinomas, which occur sporadically, familial or hereditary. Adenomas and intraepithelial neoplasms are considered as precursor lesions. Recently, whole genome sequencing and comprehensive molecular profiling described four molecular subtypes of gastric cancer: Epstein-Barr virus (EBV) positive, microsatellite unstable, chromosomal unstable and genomically stable gastric cancer. Currently, only the TNM classification has stood the test of time for the assessment of patient prognosis. Neuroendocrine tumor types 1-3 and soft tissue tumors occur significantly less often in the stomach. Gastrointestinal stromal tumors and inflammatory fibroid polyps are among the more common soft tissue tumors of the stomach and show distinct phenotypes. This review gives an overview of the current World Health Organization (WHO) classification of gastric tumors.

Cancer predisposition syndromes: lessons for truly precision medicine

Cancer predisposition syndromes are typically uncommon, monogenic, high-penetrance disorders. Despite their rarity, they have proven to be highly clinically relevant in directing cancer prevention strategies. As such, they share notable similarities with an expanding class of low-frequency somatic mutations that are associated with a striking prognostic or predictive effect in the tumours in which they occur. In this review, we highlight these commonalities, with particular reference to mutations in the proofreading domain of replicative DNA polymerases. These molecular phenotypes may occur as either germline or somatic events, and in the latter case, have been shown to confer a favourable prognosis and potential increased benefit from immune checkpoint inhibition. We note that incorporation of these variants into clinical management algorithms will help refine patient management, and that this will be further improved by the inclusion of other germline variants, such as those that determine the likelihood of benefit or toxicity from anti-neoplastic therapy. Finally, we propose that such integrated patient and tumour profiling will be essential if we are to deliver truly precision medicine for cancer patients, but in a similar way to rare germline mutations, we must ensure that we identify and utilize rare somatic mutations with strong predictive and prognostic effects. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Gastric cancer

Gastric cancer is one of the leading causes of cancer-related death worldwide. Many patients have inoperable disease at diagnosis or have recurrent disease after resection with curative intent. Gastric cancer is separated anatomically into true gastric adenocarcinomas and gastro-oesophageal-junction adenocarcinomas, and histologically into diffuse and intestinal types. Gastric cancer should be treated by teams of experts from different disciplines. Surgery is the only curative treatment. For locally advanced disease, adjuvant or neoadjuvant therapy is usually implemented in combination with surgery. In metastatic disease, outcomes are poor, with median survival being around 1 year. Targeted therapies, such as trastuzumab, an antibody against HER2 (also known as ERBB2), and the VEGFR-2 antibody ramucirumab, have been introduced. In this Seminar, we present an update of the causes, classification, diagnosis, and treatment of gastric cancer.

Systematic review with meta-analysis: fundic gland polyps and proton pump inhibitors

BACKGROUND

A causal association between proton pump inhibitor (PPI) use and fundic gland polyps has been suggested, but the data are conflicting.

AIM

To clarify the relationship through a meta-analysis of the existing data.

METHODS

A systematic retrieval and selection of records was performed. The main inclusion criteria were original studies reporting the prevalence of fundic gland polyps in PPI users or the reverse, compared to controls. Key outcomes were the odds ratios (OR) for fundic gland polyp prevalence in association with PPI use, prevalence of PPI use amongst subjects with fundic gland polyps and fundic gland polyp prevalence among PPI users. Statistical analysis was performed using Mix 2.0 Pro.

RESULTS

The initial search using electronic databases and manual searching retrieved 339 peer-reviewed articles and abstracts. Twenty articles met all inclusion and exclusion criteria, with a total of 40 218 subjects included. The meta-analysis of 12 studies revealed an increase in fundic gland polyps amongst PPI users compared to controls (OR 2.46, 95% CI 1.42-4.27, P = 0.001), particularly among individuals taking PPIs for at least 6 months (OR: 4.71, 95% CI 2.22-9.99, P < 0.001) or 12 months (OR: 5.32, 95% CI 2.58-10.99, P < 0.001).

CONCLUSIONS

Proton pump inhibitor usage is associated with a significantly increased prevalence of fundic gland polyps, and there is a trend for this to increase with longer length of PPI exposure. However, the meta-analysis is limited mainly to cohort studies.

The first European family with gastric adenocarcinoma and proximal polyposis of the stomach: case report and review of the literature

BACKGROUND AND AIMS

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) has to date been recognized in only 8 families worldwide. Recently, different point mutations within the Ying Yang 1 (YY1) binding motif in promoter 1B of the APC gene were assigned as causal in 6 families with GAPPS.

METHODS

We diagnosed GAPPS across 3 generations in a Czech white family.

RESULTS

The proband's mother died of gastric cancer at 49 years of age. The proband died of gastric cancer at 56 years of age. All 3 of the proband's daughters inherited polyposis, involving exclusively the gastric fundus and body, with relative sparing of the lesser curve. The daughters have all been regularly surveyed endoscopically. Polyposis progressed rapidly with intestinal differentiated low-grade and high-grade dysplasia present on polypectomy specimens 5 years after the original diagnosis. On this basis, all 3 of the proband's daughters were scheduled for prophylactic total gastrectomy. Unfortunately, the middle daughter presented with generalized gastric adenocarcinoma and died at the age of 26 years. The other 2 daughters (aged 30 and 23 years) underwent total gastrectomy within 6 weeks of their sister's death; histology of surgical specimens showed gastric adenocarcinoma stage IA (pT1a, N0, M0) in both cases. Bi-directional Sanger sequencing of promoter 1B revealed a point mutation (c.-191 T>C) in all 3 daughters of the proband.

CONCLUSIONS

Atypical endoscopic progression of the fundic gland polyposis, with the presence of dysplasia on polypectomy specimens and genetic testing with recently discovered mutations in promoter 1B of the APC gene might help clinicians to decide whether prophylactic gastrectomy should be performed.

Gastric carcinoma in canines and humans, a review

Gastric carcinoma (GC) is the most common neoplasm in the stomach of dogs. Although incidence in the general population is reported to be low, breed-specific GC has a high incidence. Median age at presentation ranges from 8 to approximately 10 years. The disease is mostly located in the lesser curvature and antropyloric region of the stomach. Unfortunately, diagnosis is usually made when the disease is at an advanced stage and, therefore, prognosis is poor. Due to similarities in clinical presentation, diagnosis, histology and prognosis, canine GC may serve as a valuable model for human GC. Extensive pedigrees of canine gastric carcinoma cases could reveal insights for human gastric carcinoma. Putative species differences include the role of Helicobacter in pathogenesis, the wide array of genetic data and screening available for humans, and treatment protocols that are available for human GC.

β-Catenin activation in fundic gland polyps, gastric cancer and colonic polyps in families afflicted by 'gastric adenocarcinoma and proximal polyposis of the stomach' (GAPPS)

AIM

To evaluate possible colon involvement in the 'gastric adenocarcinoma and proximal polyposis of the stomach' (GAPPS) gastrointestinal polyposis syndrome.

METHODS

Prospective clinicopathological evaluation of two GAPPS families and expression of nuclear β-catenin, p53 and Ki67 measured by immunohistochemistry on endoscopic and surgical specimens from patients with GAPPS.

RESULTS

Patients with the GAPPS phenotype were more frequently affected by colonic polyps than patients at risk within the same families (p<0.01). Colonic polyps shared immunohistochemical features of fundic gland polyps and gastric cancers including increased expression of nuclear β-catenin, Ki67 and p53. Both gastric and colonic lesions harboured activating somatic variants of β-catenin signalling.

CONCLUSIONS

Similarities in expression markers in fundic gland and colonic polyps, together with an enrichment of colonic adenomas in family members affected by GAPPS phenotype compared with family members at risk, support mild colonic involvement of this rare cancer syndrome. Colonoscopic screening might be warranted.

CLINICAL TRIAL REGISTRATION NUMBER

#09-C-0079; Results.

Clinical impact of tumour biology in the management of gastroesophageal cancer

The characterization of oesophageal and gastric cancer into subtypes based on genotype has evolved in the past decade. Insights into the molecular landscapes of gastroesophageal cancer provide a roadmap to assist the development of new drugs and their use in combinations, for patient stratification, and for trials of targeted therapies. Trastuzumab is the only approved treatment for gastroesophageal cancers that overexpress HER2. Acquired resistance usually limits the duration of response to this treatment, although a number of new agents directed against HER2 have the potential to overcome or prolong the time until resistance occurs. Beyond that, anti-VEGFR2 therapy with ramucirumab was the first biological treatment strategy to produce a survival benefit in an unselected population of patients with chemotherapy-refractory gastroesophageal cancer. Large initiatives are starting to address the role of biomarker-driven targeted therapy in the metastatic and in the perioperative setting for patients with this disease. Immunotherapy also holds promise, and our understanding of subsets of gastroesophageal cancer based on patterns of immune response continues to evolve. Efforts are underway to identify more relevant genomic subsets through genomic screening, functional studies, and molecular characterization. Herein, we provide an overview of the key developments in the treatment of gastroesophageal cancer, and discuss potential strategies to further optimize therapy by targeting disease subtypes.

Point Mutations in Exon 1B of APC Reveal Gastric Adenocarcinoma and Proximal Polyposis of the Stomach as a Familial Adenomatous Polyposis Variant

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is an autosomal-dominant cancer-predisposition syndrome with a significant risk of gastric, but not colorectal, adenocarcinoma. We mapped the gene to 5q22 and found loss of the wild-type allele on 5q in fundic gland polyps from affected individuals. Whole-exome and -genome sequencing failed to find causal mutations but, through Sanger sequencing, we identified point mutations in APC promoter 1B that co-segregated with disease in all six families. The mutations reduced binding of the YY1 transcription factor and impaired activity of the APC promoter 1B in luciferase assays. Analysis of blood and saliva from carriers showed allelic imbalance of APC, suggesting that these mutations lead to decreased allele-specific expression in vivo. Similar mutations in APC promoter 1B occur in rare families with familial adenomatous polyposis (FAP). Promoter 1A is methylated in GAPPS and sporadic FGPs and in normal stomach, which suggests that 1B transcripts are more important than 1A in gastric mucosa. This might explain why all known GAPPS-affected families carry promoter 1B point mutations but only rare FAP-affected families carry similar mutations, the colonic cells usually being protected by the expression of the 1A isoform. Gastric polyposis and cancer have been previously described in some FAP-affected individuals with large deletions around promoter 1B. Our finding that GAPPS is caused by point mutations in the same promoter suggests that families with mutations affecting the promoter 1B are at risk of gastric adenocarcinoma, regardless of whether or not colorectal polyps are present.

Pathology and Genetics of Syndromic Gastric Polyps

Gastric polyps are found in 1% to 4% of patients undergoing gastroscopy. The vast majority are sporadic, but some gastric polyps indicate an underlying syndrome. Gastric polyps can manifest in each of the gastrointestinal polyposis syndromes, including the recently described gastric adenocarcinoma and proximal polyposis of the stomach syndrome. In addition, gastric polyps occur in Lynch syndrome and in a few rare conditions that are not primarily gastrointestinal. While some of these syndromes are clearly associated with an increased risk of gastric cancer, others are not. Interestingly, even in disorders with a well-established risk of gastric cancer, the neoplastic potential and the precursor status of these gastric polyps are not always clear. Although rare, recognition of syndromic gastric polyps is important for individual patient management. These conditions also serve as important models to study gastric homeostasis and gastric tumorigenesis.

Exome sequencing reveals three novel candidate predisposition genes for diffuse gastric cancer

Gastric cancer is the fourth most common cancer worldwide and the second leading cause of cancer mortality. Three hereditary gastric cancer syndromes have been described; hereditary diffuse gastric cancer (HDGC), familial intestinal gastric cancer (FIGC) and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). Thirty per cent of HDGC families have heterozygous germline mutations in CDH1, which encodes E-cadherin. A germline truncating mutation in the gene encoding α-E-catenin (CTNNA1) was also recently discovered in a family with HDGC, but no other genes specifically predisposing to gastric cancer have been identified, leaving the majority of cases showing familial aggregation without a known genetic cause. The aim of this study was to find the putative gastric cancer predisposing gene defect in a family with HDGC that had previously been tested negative for mutations in CDH1. In this family, there were six cases of diffuse gastric cancer in two generations. Exome sequencing was applied to two affected family members. The shared variants which were predicted deleterious in silico and could not be found in databases or in a control set of over 4,000 individuals were Sanger sequenced in a third family member. Three candidate variants were identified: p.Glu1313Lys in Insulin receptor (INSR), p.Arg81Pro in F-box protein 24 (FBXO24) and p.Pro1146Leu in DOT1-like histone H3K79 methyltransferase (DOT1L). These variants and adjacent regions were screened for in an additional 26 gastric cancer patients with a confirmed (n = 13) or suspected (n = 13) family history of disease, but no other non-synonymous mutations were identified. This study identifies INSR, FBXO24 and DOT1L as new candidate diffuse gastric cancer susceptibility genes, which should be validated in other populations. Of these genes, INSR is of special interest as insulin signaling was recently shown to affect tumor cell invasion capability by modulating E-cadherin glycosylation.

[Hereditary gastric and pancreatic cancer predisposition syndromes]

The most common hereditary gastrointestinal cancers are colorectal, mainly hereditary nonpolyposis colorectal cancer (Lynch syndrome) and familial adenomatous polyposis. Other extracolonic neoplasms, including the gastric and pancreatic adenocarcinomas, are less well known and studied because they account for a relatively small percentage of hereditary gastrointestinal cancers. Nonetheless, they merit special attention because of the high associated morbidity and mortality rates. We review the hereditary and familial syndromes associated with gastric and pancreatic cancers with a view to improving knowledge and understanding of these diseases, in order to heighten diagnostic suspicion and thus implement appropriate diagnostic strategies, screening, surveillance and treatment.

Syndromic Gastric Polyps: At the Crossroads of Genetic and Environmental Cancer Predisposition

Gastric polyps occur in 1-4 % of patients undergoing gastroscopy. Although most are sporadic, some gastric polyps are part of an underlying hereditary syndrome. Gastric polyps can be seen in each of the well-known gastrointestinal polyposis syndromes, but also in Lynch syndrome and in several rare not primarily gastrointestinal syndromes. In addition, Gastric Adenocarcinoma and Proximal Polyposis of the Stomach (GAPPS) is a recently described heritable syndrome characterized by isolated gastric polyposis and risk of gastric cancer.Some of these syndromes are associated with an increased risk of gastric cancer, whereas others are not. However, the neoplastic potential and the precursor status of these gastric polyps are not always clear, even in syndromes with a well-established risk of gastric cancer. For instance, the neoplastic potential of Peutz-Jeghers polyps is debatable, despite the well-established risk of gastric cancer in this syndrome. Also fundic gland polyps and gastric foveolar-type adenomas in FAP carry a low risk of malignant transformation. In contrast, gastric juvenile polyps are precursor lesions of gastric cancer in juvenile polyposis syndrome through neoplastic progression of juvenile polyps in these patients.Although these hereditary syndromes with gastric polyps are rare, recognition is important for individual patient management. Furthermore, the initiation and progression of these lesions can be influenced by environmental factors such as Helicobacter Pylori infection. This makes these rare lesions an appropriate model for understanding the clonal evolution of early gastric cancer in the wider population.

Histopathological, Molecular, and Genetic Profile of Hereditary Diffuse Gastric Cancer: Current Knowledge and Challenges for the Future

Familial clustering is seen in 10 % of gastric cancer cases and approximately 1-3 % of gastric cancer arises in the setting of hereditary diffuse gastric cancer (HDGC). In families with HDGC, gastric cancer presents at young age. HDGC is predominantly caused by germline mutations in CDH1 and in a minority by mutations in other genes, including CTNNA1. Early stage HDGC is characterized by a few, up to dozens of intramucosal foci of signet ring cell carcinoma and its precursor lesions. These include in situ signet ring cell carcinoma and pagetoid spread of signet ring cells. Advanced HDGC presents as poorly cohesive/diffuse type carcinoma, normally with very few typical signet ring cells, and has a poor prognosis. Currently, it is unknown which factors drive the progression towards aggressive disease, but it is clear that most intramucosal lesions will not have such progression.Immunohistochemical profile of early and advanced HDGC is often characterized by abnormal E-cadherin immunoexpression, including absent or reduced membranous expression, as well as "dotted" or cytoplasmic expression. However, membranous expression of E-cadherin does not exclude HDGC. Intramucosal HDGC (pT1a) presents with an "indolent" phenotype, characterized by typical signet ring cells without immunoexpression of Ki-67 and p53, while advanced carcinomas (pT > 1) display an "aggressive" phenotype with pleomorphic cells, that are immunoreactive for Ki-67 and p53. These features show that the IHC profile is different between intramucosal and more advanced HDGC, providing evidence of phenotypic heterogeneity, and may help to define predictive biomarkers of progression from indolent to aggressive, widely invasive carcinomas.

Ménétrier's Disease: Its Mimickers and Pathogenesis

Ménétrier’s disease is a rare protein-losing hypertrophic gastropathy. Histologically, it can be mistaken for other disorders showing hypertrophic gastropathy. The pathogenesis of Ménétrier’s disease is not fully understood; however, it appears that the epidermal growth factor receptor (EGFR) ligand, transforming growth factor alpha, contributes to the pathogenesis of this disorder. In this review, we will discuss disease entities that can mimic Ménétrier’s disease and the role of EGFR signaling in Ménétrier’s disease.

Familial Gastric Cancers

Although the majority of gastric carcinomas are sporadic, approximately 10% show familial aggregation, and a hereditary cause is determined in 1%-3% cases. Of these, hereditary diffuse gastric cancer is the most recognized predisposition syndrome. Although rare, the less commonly known syndromes also confer a markedly increased risk for development of gastric cancer. Identification and characterization of these syndromes require a multidisciplinary effort involving oncologists, surgeons, genetic counselors, biologists, and pathologists. This article reviews the molecular genetics, clinical and pathologic features, surveillance guidelines, and preventive measures of common and less common hereditary gastric cancer predisposition syndromes.

Epithelial dysplasia of the stomach with gastric immunophenotype shows features of biological aggressiveness

BACKGROUND

Gastric dysplasia is classified as adenomatous/type I (intestinal phenotype) and foveolar or pyloric/type II (gastric phenotype) according to morphological (architectural and cytological) features. The immunophenotypic classification of dysplasia, based on the expression of the mucins, CD10 and CDX2, recognizes the following immunophenotypes: intestinal (MUC2, CD10, and CDX2); gastric (MUC5AC and/or MUC6, absence of CD10, and absent or low expression of CDX2); hybrid (gastric and intestinal markers); and null.

METHODS

Sixty-six cases of nonpolypoid epithelial dysplasia of the stomach were classified according to morphological features (histotype and grade) and immunophenotype. Immunohistochemical staining was performed with antibodies against MUC2, MUC5AC, MUC6, CD10, CDX2, chromogranin, synaptophysin, Ki-67, and TP53. HER2 alterations were analyzed by immunohistochemistry and silver-enhanced in situ hybridization.

RESULTS

By conventional histology, dysplasia was classified as adenomatous/intestinal (n = 42; 64 %) and foveolar or pyloric/gastric (n = 24; 36 %) and graded as low grade (n = 37; 56 %) or high grade (n = 29; 44 %). Immunophenotypic classification showed intestinal (n = 22; 33.3 %), gastric (n = 25; 37.9 %), hybrid (n = 17; 25.8 %), or null (n = 2; 3.0 %) phenotypes. In 20 cases a coexistent intramucosal carcinoma was identified. The intestinal immunophenotype was shown to be significantly associated with low-grade dysplasia (p = 0.001), high expression of CDX2 (p = 0.015), TP53 (p = 0.034), synaptophysin (p = 0.003), and chromogranin (p < 0.0001); the gastric immunophenotype was significantly associated with high-grade dysplasia (p = 0.001), high Ki-67 proliferative index (p = 0.05), and coexistence of intramucosal carcinoma (p = 0.013). HER2 amplification was observed in 3 cases, typed as gastric or hybrid.

CONCLUSIONS

Epithelial nonpolypoid dysplasia of the stomach with gastric immunophenotype shows features of biological aggressiveness and may represent the putative precursor lesion in a pathway of gastric carcinogenesis originated de novo from the native gastric mucosa, leading to gastric-type adenocarcinoma.