Pathology and Clinical Relevance of Gastric Epithelial Dysplasia

Gastric dysplasia is defined as an unequivocally neoplastic epithelium. Dysplastic lesions are characterized by cellular atypia reflective of abnormal differentiation and disorganized glandular architecture. The last few years have been marked by a refinement of the prognosis and risk of progression of gastric dysplasia and the recognition of novel morphologic patterns of dysplasia. Determination of the correct diagnosis and grade of dysplasia are critical steps since it will be predicting the risk of malignant transformation and help tailor appropriate surveillance strategy. This review describes the morphologic characteristics of conventional dysplasia and nonconventional gastric dysplasia that have been more recently characterized.

Two Cases, Too Little, Too Late: Surveillance for Gastric Cancer in Patients with FAP

Familial adenomatous polyposis is an autosomal dominant disease due to a mutation in the adenomatous polyposis coli (APC) gene. The disease, characterized by the development of adenomas throughout the colon and rectum, is also associated with extracolonic manifestations including gastric fundic polyps and cancer. In this report, we describe two patients with FAP with advanced gastric adenocarcinoma who received systemic chemotherapy. We reviewed the literature published over the past two decades on gastric cancer in FAP patients to assess the clinical course of this disease. Due to its recent increased incidence in Western countries, close endoscopic surveillance to detect early gastric neoplastic lesions is recommended.

Fundic Gland Polyps Lack DNA Content Abnormality Characteristic of Other Adenomatous Precursor Lesions in the Gastrointestinal Tract

Fundic gland polyps (FGPs) develop sporadically (frequently after proton pump inhibitor therapy) or in the setting of a hereditary polyposis syndrome, such as familial adenomatous polyposis (FAP). FAP-related FGPs often demonstrate low-grade dysplasia (LGD) and are frequently associated with APC mutations, even in the absence of dysplasia. Sporadic FGPs with dysplasia are molecularly similar to FAP-related FGPs and demonstrate frequent mutations in APC gene. Despite having similar molecular alterations with colorectal and other adenomatous precursor lesions in the gastrointestinal (GI) tract, FGPs rarely progress to advanced gastric neoplasia (high-grade dysplasia [HGD] or adenocarcinoma), and their role in gastric tumorigenesis remains unclear but likely limited. The clinicopathologic features of 192 patients diagnosed with FGPs, including 86 with FAP-related FGPs (33 with dysplastic FGPs and 53 with nondysplastic FGPs) and 106 with sporadic FGPs (12 with dysplastic FGPs and 94 with nondysplastic FGPs), were analyzed. DNA flow cytometry was performed on 111 FAP-related FGP biopsies, including 32 FGPs with LGD and 79 nondysplastic FGPs, to assess the presence of abnormal DNA content (ie, aneuploidy or elevated 4N fraction). Moreover, 40 sporadic FGP biopsies, including 14 dysplastic (13 LGD and 1 HGD) and 26 nondysplastic FGPs, were examined for DNA content abnormality. Patients with FAP and nondysplastic FGPs were more likely to be younger (mean age, 32 years) and present with multiple FGPs (92%, defined as having ≥2 FGPs) than those with sporadic nondysplastic FGPs (61 years and 65%, respectively; P < .001). They also recorded higher rates of previous or concurrent gastric epithelial dysplasia not occurring in a FGP (8%, P = .016), nongastric GI dysplasia (96%, P < .001), and nongastric GI malignancy (17%, P = .001) compared with those with sporadic nondysplastic FGPs (0%, 52%, and 2%, respectively). The sporadic group was more frequently associated with proton pump inhibitor therapy (78%, P < .001), gastric intestinal metaplasia (24%, P = .004), and a family history of gastric cancer (10%, P = .027) than the FAP group (19%, 6%, and 0%, respectively). Almost all FAP-related FGPs had a polypoid endoscopic appearance (98% vs 84% for sporadic FGPs; P = .009). The mean size of the largest FAP-related FGPs (0.5 cm) was similar to that of sporadic FGPs (0.7 cm) (P = .069). None of the 147 patients with FAP-related or sporadic nondysplastic FGPs were associated with subsequent detection of advanced gastric neoplasia within a mean follow-up time of 54 months (range, <1 to 277 months). However, 2 (4%) of the 45 patients with FAP-related or sporadic dysplastic FGPs developed advanced gastric neoplasia within a mean follow-up time of 59 months (range, <1 to 236 months). One (3%) of the 33 patients with FAP and dysplastic FGPs developed signet ring cell adenocarcinoma, whereas 1 (8%) of the 12 patients with sporadic dysplastic FGPs developed HGD (P = .445). However, none of the FAP-related and sporadic FGP biopsies, regardless of the presence or absence of dysplasia, demonstrated DNA content abnormality. In conclusion, FGPs lack large-scale chromosomal changes that are characteristic of the typical adenoma-carcinoma sequence involved in the development of other GI malignancies. Progression to advanced gastric neoplasia is rare in FGPs, which may be partly explained by the apparent lack of the chromosomal instability phenotype in these lesions.

Epidemiology and Characteristics of Gastric Carcinoma in Childhood-An Analysis of Data from Population-Based and Clinical Cancer Registries

(1) Background: Gastric carcinoma is an exceptionally rare tumor in childhood. Little is known about the etiology, epidemiology, and clinical features of pediatric gastric carcinomas. This analysis aimed to fill this gap by increasing knowledge about the occurrence of gastric carcinoma in childhood. (2) Material and methods: Data from gastric carcinoma cases diagnosed between 2000 and 2017/2018 were retrieved from the Surveillance, Epidemiology, and End Results Program (SEER) and the German Center for Cancer Registry Data. Data from patients <20 years of age were analyzed for patient- and tumor-related characteristics. In addition, clinical data from patients with gastric carcinoma registered in the German Registry for Rare Pediatric Tumors (STEP) were analyzed for diagnostics, therapy, and outcome. (3) Results: Ninety-one cases of gastric carcinoma, mainly in adolescents, were identified in the epidemiologic cancer registries. Among patients with recorded staging data, advanced tumor stages were common (66.7%). Within the follow-up period covered, 63.7% of patients with clinical follow-up data died. Eight pediatric patients with gastric carcinoma were enrolled in the STEP registry, among whom two were patients with hereditary CDH1 mutations and another was a patient with Peutz−Jeghers syndrome. Three patients were found to have distinctly decreased immunoglobulin concentrations. All four patients in whom complete resection was achieved remained in remission. Three of the other four patients died despite multimodal therapy. (4) Conclusions: A combination of Helicobacter pylori infection and tumor predisposition and/or immunodeficiency appears to promote the development of gastric carcinoma in childhood. While patients with localized disease stages have a good chance of achieving durable remission through complete resection, patients with stage IV carcinomas face a dismal prognosis, highlighting the need to develop new strategies such as mutation-guided treatments.

Endoscopic findings of gastric neoplasms in familial adenomatous polyposis are associated with the phenotypic variations and grades of dysplasia

Patients with familial adenomatous polyposis (FAP) are at increased risk of developing gastric neoplasms. However, endoscopic findings have not been sufficiently investigated. We investigated the phenotypic expression of gastric adenoma (low-grade dysplasia) and gastric cancer (high-grade dysplasia or carcinoma) in patients with FAP and clarified their relationships to endoscopic findings. Of 29 patients with FAP who underwent esophagogastroduodenoscopy between 2005 and 2020, 11 (38%) had histologically confirmed gastric neoplasms, including 23 lesions of gastric adenoma and 9 lesions of gastric cancer. The gastric neoplasms were classified into 3 phenotypes (gastric, mixed, or intestinal type) according to the immunostaining results and evaluated for location (U or M region: upper or middle third of the stomach or L region: lower third of the stomach), color (same as the background mucosa, whitish, or reddish), macroscopic type (elevated, flat, or depressed), background mucosal atrophy (present or absent), fundic gland polyps in the surrounding mucosa (present or absent), and morphologic changes in tumor size. Elevated whitish gastric adenomas were further subdivided by macroscopic type (flat elevated, protruded, or elevated with a central depression) and color (milky- or pinkish-white). The gastric adenomas included gastric (11/23, 48%), mixed (4/23, 17%), and intestinal (8/23, 35%) phenotypes. In contrast, no lesions of gastric cancers showed a gastric phenotype (0/9, 0%), while 5 (56%) and 4 (44%) lesions were intestinal and mixed phenotypes, respectively. Gastric cancers were significantly more likely than gastric adenomas to present as reddish depressed lesions with gastric atrophy. All gastric-type adenomas occurred in non-atrophic mucosa, in mucosa with fundic gland polyps in the periphery, in the U or M region, and as flat elevated or protruded lesions with a milky-white color. Half of the lesions increased in size. Meanwhile, the typical endoscopic features of intestinal-type adenomas included occurrence in the L region and elevated pinkish-white lesions with central depression. None of the intestinal-type adenomas increased in size during the observation period. We believe that these endoscopic features will be useful for the prompt diagnosis and appropriate management of gastric neoplasms in patients with FAP.

High interobserver variability and frequent overdiagnosis of dysplasia in fundic gland polyps can be improved by detecting atypia on the surface epithelium and an abrupt transition to non-neoplastic cells

AIMS

Fundic gland polyps (FGPs) arise sporadically and in combination with familial adenomatous polyposis (FAP). Criteria for distinguishing low-grade dysplasia (LGD) from regenerative atypia in FGPs are not well established. The aims of study were to determine: (i) interobserver variability in diagnosing LGD in FGPs; (ii) bias in diagnosing LGD in FAP patients; and (iii) stringent criteria for LGD in FGPs.

METHODS AND RESULTS

Five senior pathologists who were blinded to the clinical history reviewed 72 FAP-associated FGPs and 34 sporadic FGPs. Cases were classified as negative (score = 0) or positive (score = 1) for LGD. Each case was assigned a 'combined dysplasia score' (CDS) ranging from 0 to 5 to reflect all five opinions. Fleiss' kappa showed only moderate interobserver agreement (κ = 0.46). Forty-one FGPs were classified as negative for dysplasia by consensus (CDS = 0-1), including 10 (24%) originally diagnosed as LGD. In contrast, all 37 cases classified as LGD by consensus (CDS = 4-5) were originally diagnosed as LGD, indicating that overdiagnosis of dysplasia is more common than underdiagnosis (P = 0.0012). Cytological atypia in the surface epithelium and an abrupt transition between atypical and normal-appearing epithelium were the most sensitive (97% and 100%, respectively) and specific (100% and 98%, respectively) features of dysplasia (P < 0.0001 for both comparisons). Very good agreement was achieved when a diagnosis of dysplasia was based on the presence of both features (κ = 0.85).

CONCLUSIONS

There is high interobserver variability and a tendency to overdiagnose LGD in FGPs. Strict criteria requiring both surface atypia and abrupt transition for LGD in FGPs result in low interobserver variability.

Prevalence and endoscopic treatment outcomes of upper gastrointestinal neoplasms in familial adenomatous polyposis

BACKGROUND

Although upper gastrointestinal (GI) neoplasms are not rare in patients with familial adenomatous polyposis (FAP), few studies have focused on them and the long-term outcomes of their treatment by endoscopy. Therefore, we aimed to investigate the prevalence and endoscopic treatment outcomes of upper GI neoplasms in patients with FAP.

METHODS

Among 215 patients diagnosed with FAP between January 1991 and December 2019, 208 who underwent esophagogastroduodenoscopy were eligible. The clinical features and endoscopic treatment outcomes of upper GI neoplasms were retrospectively investigated and analyzed.

RESULTS

Among the enrolled patients, 113 (54.3%) had one or more upper GI neoplasms: gastric adenoma (n = 34), gastric cancer (n = 7), nonampullary duodenal adenoma (n = 86), and ampullary adenoma (n = 53). Among patients with gastric neoplasms (n = 37), 24 (64.9%) underwent treatment (endoscopic treatment: 22, surgery: 2). No tumor-related mortality occurred during median follow-up of 106 months (interquartile range [IQR] 63-174). Endoscopic treatment was performed in 47 (54.7%) of 86 patients with nonampullary duodenal adenoma and in 32 (60.4%) of 53 patients with ampullary adenoma. No patient underwent surgery for duodenal neoplasms, and no tumor-related mortality occurred during median follow-up of 88 months (IQR 42-145). The proportion of patients with increased Spigelman stage at 2 years after the initial diagnosis or treatment was significantly higher in untreated group than in the group treated for duodenal neoplasms (27.3% vs. 0.0%, p = 0.001).

CONCLUSION

Endoscopic surveillance in FAP patients is important for the detection and treatment of upper GI neoplasms in early stage. In particular, endoscopic therapy for duodenal neoplasms can reduce the severity of duodenal polyposis.

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) - A Helicobacter-opposite point

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is a rare familial gastric cancer syndrome with an autosomal dominant pattern of inheritance. It is characterised by fundic gland polyposis of the gastric body and is associated with a significant risk of gastric adenocarcinoma. Unlike sporadic gastric cancer, Helicobacter pylori is usually absent in patients with GAPPS. This opposite-point finding has so far not been fully clarified. Prophylactic total gastrectomy is indicated in all cases of GAPPS with fundic gland polyposis and the presence of any dysplasia. If no dysplasia is found at histology, prophylactic gastrectomy is suggested at between 30 and 35 years of age, or at five years earlier than the age at which the youngest family member developed gastric cancer. Different phenotypes of GAPPS demand an individual approach to particular family members.

American Society for Gastrointestinal Endoscopy guideline on the role of endoscopy in familial adenomatous polyposis syndromes

Familial adenomatous polyposis (FAP) syndrome is a complex entity, which includes FAP, attenuated FAP, and MUTYH-associated polyposis. These patients are at significant risk for colorectal cancer and carry additional risks for extracolonic malignancies. In this guideline, we reviewed the most recent literature to formulate recommendations on the role of endoscopy in this patient population. Relevant clinical questions were how to identify high-risk individuals warranting genetic testing, when to start screening examinations, what are appropriate surveillance intervals, how to identify endoscopically high-risk features, and what is the role of chemoprevention. A systematic literature search from 2005 to 2018 was performed, in addition to the inclusion of seminal historical studies. Most studies were from worldwide registries, which have compiled years of data regarding the natural history and cancer risks in this cohort. Given that most studies were retrospective, recommendations were based on epidemiologic data and expert opinion. Management of colorectal polyps in FAP has not changed much in recent years, as colectomy in FAP is the standard of care. What is new, however, is the developing body of literature on the role of endoscopy in managing upper GI and small-bowel polyposis, as patients are living longer and improved endoscopic technologies have emerged.

Recurrent Mutations in APC and CTNNB1 and Activated Wnt/β-catenin Signaling in Intraductal Papillary Neoplasms of the Bile Duct: A Whole Exome Sequencing Study

This study aimed to elucidate the genetic landscape of biliary papillary neoplasms. Of 28 cases examined, 7 underwent whole exome sequencing, while the remaining 21 were used for validation studies with targeted sequencing. In the whole exome sequencing study, 4/7 cases had mutations in either APC or CTNNB1, both of which belong to the Wnt/β-catenin pathway. Somatic mutations were also identified in genes involved in RAS signaling (KRAS, BRAF), a cell cycle regulator (CDC27), histone methyltransferase (KMT2C, KMT2D), and DNA mismatch repair (MSH3, MSH6, PMS1). Combined with discovery and validation cohorts, mutations in APC or CTNNB1 were observed in 6/28 subjects (21%) and were mutually exclusive. When the cases were classified into intraductal papillary neoplasms of the bile duct (IPNBs, n=14) and papillary cholangiocarcinomas (n=14) based on the recently proposed classification criteria, mutations in APC and CTNNB1 appeared to be entirely restricted to IPNBs with 6/14 cases (43%) harboring mutations in either gene. These genetic alterations were detected across the 3 nonintestinal histologic types. In immunohistochemistry, the aberrant cytoplasmic and/or nuclear expression of β-catenin was found in not only 5/6 IPNBs with APC or CTNNB1 mutations, but also 6/8 cases with wild-type APC and CTNNB1 (total 79%). In addition, APC and CTNNB1 alterations were exceptional in nonpapillary cholangiocarcinomas (n=29) with a single case harboring CTNNB1 mutation (3%). This study demonstrated recurrent mutations in APC and CTNNB1 in nonintestinal-type IPNBs, suggesting that activation of the Wnt/β-catenin signaling pathway is relevant to the development and progression of IPNBs.

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.

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.

Gastric tumours in FAP

Gastric cancer is not a recognised extra-colonic manifestation of FAP, except in countries with a high prevalence of gastric cancer. Data regarding gastric adenomas in FAP are sparse. The aim of this study was to review the clinical characteristics of gastric tumours occurring within an FAP population from the largest European polyposis registry. All patients that developed a gastric adenoma or carcinoma were identified from a prospectively maintained registry database. The primary outcome measure was the occurrence of gastric adenoma or adenocarcinoma. Secondary outcomes included APC mutation, tumour stage, management and survival. Eight patients developed gastric cancer and 21 an adenoma (median age 52 and 44 years, respectively). Regular oesophagogastroduodenoscopy surveillance was performed in 6/8 patients who developed cancer. Half were advanced T3/4 tumours and 6/8 had nodal or metastatic spread at diagnosis. All cancer cases died within a median of 13.5 months from diagnosis. Gastric adenomas were evenly distributed: 11/21 (52%) in the distal and 10/21 (48%) proximal stomach, whereas 5/8 (63%) cancers were located proximally. An association between gastric tumour and desmoid development was observed; 7/8 (88%) cancer and 11/21 (52%) adenoma cases had a personal or family history of desmoid. It would appear from this small, retrospective study that gastric cancer is not a prominent extra-colonic feature of FAP in the Western world. It seems to present at an advanced stage with a poor prognosis. There may be an association between gastric tumour and desmoid occurrence but a large multicentre cohort is necessary to investigate this further.

Familial Adenomatous Polyposis with Multiple Helicobacter-negative Early Gastric Cancers Treated by Endoscopic Submucosal Dissection

Stomach cancer rarely develops in patients with familial adenomatous polyposis (FAP), and Helicobacter pylori infection may increase the risk of FAP-related gastric cancer. We describe the case of a 64-year-old woman who developed multiple synchronous early gastric cancers without H. pylori infection. Nine cancer lesions were successfully treated by endoscopic submucosal dissection. An immunohistochemical analysis revealed that the tumors were positive for mucin (MUC)2, MUC6, and CDX2, but negative for MUC5AC, suggesting that the tumors were gastrointestinal mixed type. Periodical endoscopic surveillance is important for the detection of cancers at an early stage.

Surveillance of patients with hereditary gastrointestinal cancer syndromes

Gastrointestinal cancers are among the most frequent tumors. Although most cases are sporadic, up to 5-6% develops in the context of gastrointestinal hereditary syndromes. These entities have specific characteristics and often a germline mutation identified, thus allowing performing genetic counseling. This review summarizes the most common gastrointestinal hereditary syndromes, focusing on the surveillance recommendations.

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.

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.

Gastric Hamartomatous Polyps-Review and Update

Gastric polyps are frequently encountered on endoscopic examinations. While many of these represent true epithelial lesions, some of the polyps may result from underlying stromal or lymphoid proliferations or even heterotopic tissue. Histologic examination is essential for accurate typing of the polyps to predict malignant potential and underlying possible genetic abnormalities. The focus of this review is on gastric hamartomatous polyps, which are relatively rare and diagnostically challenging. Though most of the gastric hamartomatous polyps are benign, certain types are associated with increased malignant potential. These include certain polyps associated with specific genetic familial polyposis syndromes and gastric inverted hamartomatous polyps. Identification of these polyps can result in the prevention or early diagnosis of gastric carcinoma and also help in the identification of family members with polyposis syndromes. The aim of this review is to categorize gastric hamartomatous polyps and aid in the identification of high-risk categories.

[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.

Morphology and natural history of familial adenomatous polyposis-associated dysplastic fundic gland polyps

AIMS

Most patients with familial adenomatous polyposis (FAP) develop gastric fundic gland polyps, with many displaying low-grade dysplasia. This study evaluates the natural history and morphological phenotype of dysplasia in FAP-associated fundic gland polyps.

METHODS AND RESULTS

Patients with FAP and dysplastic fundic gland polyps (n = 24) were identified. Twenty-two of 24 FAP-associated dysplastic fundic gland polyps showed a gastric phenotype and two had mixed phenotype. During a mean 6.1-year follow-up (range 0.8-12.6 years) and 5.7 endoscopies (range 2-22), one patient (4%) was diagnosed with a fundic gland polyp with high-grade dysplasia, while 23 patients (96%) in this cohort had either no dysplasia or persistent low-grade dysplasia. Contemporary patients with sporadic fundic gland polyps with low-grade dyplasia had similar morphology and outcomes to the FAP-associated fundic gland polyp cohort. Dysplasia in fundic gland polyps (FAP-associated and sporadic) was associated less frequently with intestinal phenotype, high-grade dysplasia and the finding of concurrent or subsequent carcinoma compared to contemporary patients with sporadic gastric dysplasia not occurring in fundic gland polyps.

CONCLUSIONS

This cohort of patients with FAP-associated dysplastic fundic gland polyps rarely developed high-grade dysplasia and gastric adenocarcinoma was absent.

Gastric adenomas in familial adenomatous polyposis are common, but subtle, and have a benign course

Background

Patients with familial adenomatous polyposis (FAP) are known to have an increased risk for gastric adenomas. The clinical features of gastric adenomas in FAP have not been well characterized, and there is a lack of standardized approaches to the management of these lesions.

Aims

To study the endoscopic appearance, risk factors, clinical course, and response to therapy of gastric adenomas in patients with FAP.

Methods

We retrospectively reviewed the records of 97 patients with FAP who underwent esophagogastroduodenoscopy (EGD) at Mayo Clinic (Florida, Rochester and Arizona) between 2004 and 2013.

Results

Nine patients (9%) had biopsy-proven gastric adenomas. Adenomas were located in the antrum (five patients), in the body and fundus in the setting of background fundic gland polyps (FGP) (three patients), and in the body not associated with FGP (one patient). Adenoma size was 3–40 mm and the number of adenomas per patient ranged from one to 20. Adenomas in the antrum were flat and subtle, whereas those in the gastric body or fundus were polypoid and difficult to differentiate from the cystic FGPs seen in patients with FAP. The performing endoscopists reported difficulty with identifying adenomas, and six patients had at least one EGD within the previous three years where gastric adenomas were not reported. Adenomas were classified as tubular in eight patients and tubulovillous in one patient. High grade dysplasia was noted in one patient. After a median follow-up of 63 months (interquartile range: 20–149 months), no patient in our entire cohort (with or without gastric adenomas) developed gastric cancer. The patients in whom gastric adenoma developed, compared to those without gastric adenoma, were more likely to be younger [36 ± 12 vs. 48 ± 15 years, p = 0.02], have concomitant chronic gastritis [22% vs. 0%, p = 0.008], and have desmoid tumors [5 (56%) vs. 19 (22%), p = 0.04].

Conclusions

Gastric adenomas are not uncommon in patients with FAP and are often difficult to identify endoscopically. Endoscopists should have a high degree of suspicion for gastric adenomas in these patients and a low threshold to biopsy. Given the benign clinical course, recommended initial management is conservative with endoscopic therapy and periodic surveillance.

Clinical characteristics of gastric cancer in patients with familial adenomatous polyposis

Familial adenomatous polyposis is an autosomal dominant hereditary disease leading to the development of numerous colorectal polyps with malignant potential. Extra-colonic neoplasms are observed often in patients with familial adenomatous polyposis, but clinical characteristics of gastric cancer associated with familial adenomatous polyposis are not well understood. We studied the clinical characteristics of five Japanese patients who developed gastric cancer after undergoing colectomy for familial adenomatous polyposis. Gastric cancer was found on gastroduodenal endoscopy performed during postoperative follow-up in all five patients. Mean ages at the time of colectomy and at the time of diagnosis of gastric cancer were 39.2 and 58 years, respectively. Importantly, gastric fundic gland polyps were undetectable in these five patients. The mean duration between colectomy and diagnosis of gastric cancer was more than 20 years in three of five patients (mean: 19 years and 1 month). Cancers were multiple in three of five patients. Two patients developed metachronous gastric cancer in the gastric remnant. All five patients presented with well to moderately differentiated adenocarcinoma; four of the five patients were stage IA. Characteristics of the gastric cancer with familial adenomatous polyposis include a long duration between occurrence of gastric cancer and colectomy, metachronous cancers, multicentric lesions, and a high rate of well to moderately differentiated adenocarcinoma. Long-term and periodic gastroduodenal surveillance endoscopy is recommended for patients with FAP who underwent colectomy.

Acute WNT signalling activation perturbs differentiation within the adult stomach and rapidly leads to tumour formation

A role for WNT signalling in gastric carcinogenesis has been suggested due to two major observations. First, patients with germline mutations in adenomatous polyposis coli (APC) are susceptible to stomach polyps and second, in gastric cancer, WNT activation confers a poor prognosis. However, the functional significance of deregulated WNT signalling in gastric homoeostasis and cancer is still unclear. In this study we have addressed this by investigating the immediate effects of WNT signalling activation within the stomach epithelium. We have specifically activated the WNT signalling pathway within the mouse adult gastric epithelium via deletion of either glycogen synthase kinase 3 (GSK3) or APC or via expression of a constitutively active β-catenin protein. WNT pathway deregulation dramatically affects stomach homoeostasis at very short latencies. In the corpus, there is rapid loss of parietal cells with fundic gland polyp (FGP) formation and adenomatous change, which are similar to those observed in familial adenomatous polyposis. In the antrum, adenomas occur from 4 days post-WNT activation. Taken together, these data show a pivotal role for WNT signalling in gastric homoeostasis, FGP formation and adenomagenesis. Loss of the parietal cell population and corresponding FGP formation, an early event in gastric carcinogenesis, as well as antral adenoma formation are immediate effects of nuclear β-catenin translocation and WNT target gene expression. Furthermore, our inducible murine model will permit a better understanding of the molecular changes required to drive tumourigenesis in the stomach.

Whole exome sequencing of pediatric gastric adenocarcinoma reveals an atypical presentation of Li-Fraumeni syndrome

BACKGROUND

Gastric adenocarcinoma is a rare diagnosis in childhood. A 14-year-old male patient presented with metastatic gastric adenocarcinoma, and a strong family history of colon cancer. Clinical sequencing of CDH1 and APC were negative. Whole exome sequencing was therefore applied to capture the majority of protein-coding regions for the identification of single-nucleotide variants, small insertion/deletions, and copy number abnormalities in the patient's germline as well as primary tumor.

MATERIALS AND METHODS

DNA was extracted from the patient's blood, primary tumor, and the unaffected mother's blood. DNA libraries were constructed and sequenced on Illumina HiSeq2000. Data were post-processed using Picard and Samtools, then analyzed with the Genome Analysis Toolkit. Variants were annotated using an in-house Ensembl-based program. Copy number was assessed using ExomeCNV.

RESULTS

Each sample was sequenced to a mean depth of coverage of greater than 120×. A rare non-synonymous coding single-nucleotide variant (SNV) in TP53 was identified in the germline. There were 10 somatic cancer protein-damaging variants that were not observed in the unaffected mother genome. ExomeCNV comparing tumor to the patient's germline, identified abnormal copy number, spanning 6,946 genes.

CONCLUSION

We present an unusual case of Li-Fraumeni detected by whole exome sequencing. There were also likely driver somatic mutations in the gastric adenocarcinoma. These results highlight the need for more thorough and broad scale germline and cancer analyses to accurately inform patients of inherited risk to cancer and to identify somatic mutations.

A Novel Germline Mutation in Exon 15 of the APC Gene in Attenuated Familial Adenomatous Polyposis: A Report of Two Cases

Attenuated familial adenomatous polyposis (AFAP) is a variant of familial adenomatous polyposis with fewer than one hundred colorectal polyps and a later age of onset of the cancer. Here, we report two cases of AFAP within family members. Each patient demonstrated the same novel germ line mutation in exon 15 of the adenomatous polyposis coli (APC) gene and was successfully managed with sulindac after refusal to perform colectomy: a 23-year-old man with incidentally diagnosed gastric adenoma and fundic gland polyps underwent colonoscopy, and fewer than 100 colorectal polyps were found; a 48-year-old woman who happened to be the mother of the 23-year-old man also showed fewer than 100 colorectal polyps on colonoscopy. Genetic analysis revealed a novel frameshift mutation in exon 15 of the APC gene. The deletion of adenine-guanine with the insertion of thymine in c.3833-3834 resulted in the formation of stop codon 1,287 in both patients. The patients were treated with sulindac due to their refusal to undergo colectomy. The annual follow-up upper endoscopy and colonoscopy in the following 2 years revealed significant regression of the colorectal polyps in both patients.

Genetic testing by cancer site: stomach

Gastric cancer is a global public health concern, ranking as the fourth leading cause of cancer mortality, with a 5-year survival of only 20%. Approximately 10% of gastric cancers appear to have a familial predisposition, and about half of these can be attributed to hereditary germline mutations. We review the genetic syndromes and current standards for genetic counseling, testing, and medical management for screening and treatment of gastric cancer. Recently, germline mutations in the E-cadherin/CDH1 gene have been identified in families with an autosomal dominant inherited predisposition to gastric cancer of the diffuse type. The cumulative lifetime risk of developing gastric cancer in CDH1 mutation carriers is up to 80%, and women from these families also have an increased risk for developing lobular breast cancer. Prophylactic gastrectomies are recommended in unaffected CDH1 mutation carriers, because screening endoscopic examinations and blind biopsies have proven inadequate for surveillance. In addition to this syndrome, gastric cancer risk is elevated in Lynch syndrome associated with germline mutations in DNA mismatch repair genes and microsatellite instability, in hereditary breast and ovarian cancer syndrome due to germline BRCA1 and BRCA2 mutations, in familial adenomatous polyposis caused by germline APC mutations, in Li-Fraumeni syndrome due to germline p53 mutations, in Peutz-Jeghers syndrome associated with germline STK11 mutations, and in juvenile polyposis syndrome associated with germline mutations in the SMAD4 and BMPR1A genes. Guidelines for genetic testing, counseling, and management of individuals with hereditary diffuse gastric cancer are suggested. A raised awareness among the physician and genetic counseling communities regarding these syndromes may allow for increased detection and prevention of gastric cancers in these high-risk individuals.

Genetic testing by cancer site: colon (polyposis syndromes)

Hereditary colonic polyposis conditions are all characterized by high rates of cancer, but they have diverse phenotypes, genetic heterogeneity, and assorted inheritance patterns. The most well known of these conditions include familial adenomatous polyposis, attenuated familial adenomatous polyposis, MUTYH (MutY human homolog)-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and Cowden syndrome. Early recognition of these conditions is not only vital for management in affected individuals, but also for prevention and early detection in at-risk relatives. Reviewed here are the genetic testing strategies for colonic polyposis, as well as an overview of characteristic features and management considerations for these syndromes.

Familial gastric and pancreatic cancers: Diagnosis and screening

Screening for gastric and pancreatic cancers in asymptomatic individuals is not routinely practiced in the United States. While there is insufficient evidence that general population screening would reduce morbidity and/or mortality associated with these cancers, the utility of screening for individuals at increased risk warrants further study. Clinical challenges include identifying high risk individuals who would be most likely to benefit from screening and determining which screening modalities and intervals would be most effective.

Gastric adenocarcinoma with chief cell differentiation: a proposal for reclassification as oxyntic gland polyp/adenoma

Gastric adenocarcinoma with chief cell differentiation (GA-CCD) has been reported as a new, rare variant of gastric adenocarcinoma. Only 12 cases in Japanese patients have been described to date, but they demonstrate distinct clinicopathologic features. To further characterize these lesions, we have collected 10 additional cases. Patients ranged in age from 44 to 79 years (mean, 64.2 y) with a relatively equal sex distribution (6 women and 4 men). Stratified by race, 4 patients were Hispanic, 2 were White, 2 were African American, 1 was Asian (Chinese), and the race was unknown for 1 patient. All patients presented with gastroesophageal reflux that prompted an endoscopic examination. The majority of GA-CCDs were identified in the fundus (7 of 10, 70%) and the remaining in the cardia (n=3). Grossly, they were solitary and polypoid, ranging in size from 0.2 to 0.8 cm (mean, 0.4 cm). Histologically, all cases were centered in the deep mucosa, with focal involvement of surface foveolar epithelium in 3 (30%) cases but not the submucosa. The tumors consisted of clustered glands and irregular branching cords of oxyntic epithelium. Thin wisps of radiating smooth muscle separated the epithelium, but desmoplasia was distinctly absent in all cases. The oxyntic mucosa was 1 to 2 cells thick and composed of a mixture of mucous neck, parietal, and chief cells. In 7 of 10 (70%) cases, chief cells were the predominant cell type, whereas the remaining 3 cases consisted primarily of mucous neck cells. The nuclei were mildly enlarged with slight nuclear pleomorphism, but no mitotic figures were identified. In addition, necrosis, lymphovascular invasion, and perineural invasion were absent. Immunohistochemically, GA-CCDs were diffusely positive for MUC6 (10 of 10, 100%) and negative for MUC5AC (0%) and MUC2 (0%). Ki-67 immunolabeling demonstrated variable expression, with the highest areas ranging from 0.2% to 10%. Clinical follow-up was available for 9 of 10 (90%) patients and ranged from 6 to 39 months. One patient had persistence of lesion at 6 months because of incomplete removal, whereas the other 8 were disease free. In summary, GA-CCDs are solitary, mucosal lesions of the gastric cardia/fundus that arise in patients from multiple ethnic backgrounds. Considering that patients within this study and those reported previously have had neither true recurrence nor progression of disease, these lesions are best regarded as benign. Consequently, the term GA-CCD is contradictory and we prefer the descriptive term "oxyntic gland polyp/adenoma" until further studies can clarify the pathogenesis of these lesions and their natural history.

Prevalence of gastric and duodenal polyps and risk factors for duodenal neoplasm in korean patients with familial adenomatous polyposis

BACKGROUND/AIMS

The prevalence of gastric polyps, duodenal adenoma and duodenal cancer has been reported as being high among familial adenomatous polyposis (FAP) patients, but there have been no reports of this association in Korea. This study evaluated the prevalence of gastric and duodenal polyps and risk factors for duodenal neoplasm in FAP patients in Korea.

METHODS

We reviewed both initial and follow-up endoscopic results from FAP patients. We also investigated the treatment modality of duodenal adenomas and analyzed the risk factors of duodenal neoplasms by logistic regression analysis.

RESULTS

A total of 148 patients with FAP underwent esophagogastroduodenoscopy (EGD), and the fi ndings were as follows: gastric polyp 39.9% (fundic gland polyp 25.7% and gastric adenoma 14.2%), duodenal adenoma 15.5%, gastric cancer 2.7%, and duodenal cancer 0.7%. There were two cases of gastric cancer that developed from benign gastric polyps. There were progressions of duodenal adenomatosis during follow-up, and some degree of relapse occurred after endoscopic resection. Patients with gastric polyps showed a correlation with the occurrence of duodenal neoplasm (odds ratio, 2.814; p=0.024).

CONCLUSIONS

In Korean FAP patients, gastric cancer was detected more frequently, but fundic gland polyps, duodenal adenoma and duodenal cancer were detected less frequently than in Western patients. FAP patients with gastric polyps should undergo regular EGD, particularly for the early detection of duodenal neoplasia.

FAP, gastric cancer, and genetic counseling featuring children and young adults: a family study and review

Familial adenomatous polyposis is a highly complex and multifaceted colorectal cancer prone disorder which is often significantly confounded by extracolonic cancers inclusive of gastric cancer, a significant problem in the Orient. Gastric cancer in familial adenomatous polyposis is heavily influenced by fundic gland polyps which are often so voluminous as to defy effective endoscopic surveillance. This study involves more than two decades of investigation of an attenuated familial adenomatous polyposis family where gastric cancer posed an early diagnostic problem because it was obscured by multiple fundic gland polyps. Fundic gland polyps are common in familial adenomatous polyposis and attenuated familial adenomatous polyposis and, if voluminous, may interfere with effective endoscopic gastric cancer surveillance. This family is believed to be the first of its type reported with focus upon education and genetic counseling in the setting of a family information service. Cancer control in familial adenomatous polyposis may be partially resolved through use of familial colorectal cancer registries, with greater attention to family history and its interpretation, genetic counseling, and clinical translation for diagnosis and management.

Three novel mutations of the APC gene in Korean patients with familial adenomatous polyposis

Germline mutations within the adenomatous polyposis coli (APC) gene are associated with familial adenomatous polyposis (FAP), an autosomal dominant disease predisposing individuals to colorectal cancer. Identification of APC mutations has important implications for genetic counseling and management of FAP patients. We examined the APC mutation status of 10 Korean FAP patients by polymerase chain reaction-direct sequencing method and found six APC mutations, including three novel mutations. Testing for MUTYH mutation was done for FAP patients in whom no mutation in the APC gene was identified. Three novel mutations (c.1654_1663delTCTTGGCGAG, c.3709C>T, and c.6092_6094delinsTT) and three previously reported mutations (c.3631_3632delAT, c.4438C>T, and c.4612_4613delGA) were detected. The MUTYH mutation was not detected in any of the four FAP patients without an APC mutation. This finding of three novel mutations in a group of Korean FAP patients broadens the spectrum of APC mutations.

Gastric adenocarcinoma of fundic gland type (chief cell predominant type): proposal for a new entity of gastric adenocarcinoma

Only a few cases of gastric adenocarcinoma of fundic gland type have been reported. Gastric adenocarcinoma with chief cell differentiation (GA-CCD) has been recently reported as a new variant of gastric adenocarcinoma. However, its clinicopathologic features are uncertain. To elucidate them, GA-CCDs exhibiting pepsinogen-I expression (10 lesions: Group A) and randomly selected gastric adenocarcinomas of differentiated type (111 lesions: Group B) were evaluated in this study. Cell differentiation by MUC2, MUC5AC, MUC6, CD10, pepsinogen-I, H+/K+-ATPase and chromogranin A, cell proliferation by Ki-67, and overexpression of p53 protein were evaluated immunohistochemically. In Group A, all GA-CCDs were located in the upper third of the stomach. Tumors were small, with the average maximum diameter ranging from 4 to 20 (average, 8.6) mm. Histologically, GA-CCDs were well-differentiated adenocarcinomas composed of pale gray-blue, basophilic columnar cells with mild nuclear atypia, resembling chief cells. Immunohistochemically, scattered positivity for H+/K+-ATPase was observed in addition to expression of pepsinogen-I and MUC6, indicating focal differentiation toward parietal cells. In Group B, pepsinogen-I was very focally expressed in 2 cases. As these 2 cases exhibited different clinicopathological and histologic features, they cannot be categorized as GA-CCD. Mild atypism, no lymphovascular invasion, low proliferative activity, no overexpression of p53, and no recurrence indicated less aggressiveness of GA-CCD. GA-CCD is rare, but it has distinct clinicopathological characteristics, especially in terms of tumor location, histologic features, phenotypic expression, and low-grade malignancy. We propose gastric adenocarcinoma of fundic gland type (chief cell predominant type) as a new entity of gastric adenocarcinoma.

A case of gastric adenocarcinoma arising from a fundic gland polyp

A rare case of gastric adenocarcinoma arising on the surface of a fundic gland polyp is reported. A 36-year-old Japanese woman was referred to our hospital for examination and treatment of a polyp that had been detected in another hospital. She did not have a history of familial adenomatous polyposis (FAP). Endoscopic examination revealed a 10-mm-diameter fundic gland polyp in the body of the stomach. The polyp had an irregular depression on its top, suggesting the presence of malignancy. Endoscopic mucosal resection was done to make a histological diagnosis. This revealed a fundic gland polyp with a tiny superficial adenocarcinoma. Atrophic changes of the gastric mucosa were mild, although Helicobacter pylori infection was positive. It is suggested that fundic gland polyps have the potential for malignant transformation.