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

A review of APC somatic mosaicism and specific APC variants - I1307K and promotor variants

In the majority of patients with a classical Familial Adenomatous Polyposis (FAP) a pathogenic APC germline variant is identified; usually these are truncating variants in the coding region of APC. However, there are some special circumstances in which FAP is not the result of a pathogenic heterozygous germline variant in APC (mosaicism) and tspecific APC variants which do not cause FAP (I1307K and promotor variants). This paper will discuss these three conditions. APC somatic (postzygotic) mosaicism can be identified in up to 50% of unexplained adenomatous polyposis cases. The ability to identify APC postzygotic mosaicism depends on the the detection method (today usually next-generation sequencing) and also the tissue being analysed (investigation of multiple colorectal adenomas is more sensitive than leukocyte DNA). Identifying mosaicism has important implications in terms of an individual's management and managing risk in family members. The I1307K variant in APC is prevalent among Ashkenazi Jews (AJ) but can also be found in Sephardi Jews and individuals of non-Jewish descent. While this variant does not cause polyposis, it increases the risk of colorectal cancer (CRC) by 1.68-fold in AJ individuals. However, the link between the I1307K variant and CRC risk in non-AJ populations, is less well-established. Furthermore, its potential impact on other types of cancer remains unclear. Consequently, the classification of this variant, along with appropriate screening and surveillance recommendations, remains a subject of ongoing debate among leading medical and genetic organizations. Variants in the APC promotor 1B region cause the relatively newly described condition of gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). It is said to have an isolated gastric phenotype, with neither duodenal, large bowel nor extra-intestinal manifestations. There are many uncertainties regarding this condition, it's penetrance and management. Lack of clinical data and poor understanding of the natural history of the condition remain significant barriers to developing guidelines to manage this condition.

The Role of Prophylactic Gastrectomy in Gastric Adenocarcinoma and Proximal Polyposis of the Stomach: A Systematic Review

Background/Objectives: Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is a recently discovered autosomal dominant transmission disease. Patients with this condition have a higher risk of developing gastric cancer. There are numerous questions regarding the natural history of this condition, as well as concerning the diagnostic and therapeutic management of these patients. In this systematic review, we aimed to examine the current literature to determine the role of prophylactic gastrectomy in patients diagnosed with gastric adenocarcinoma and proximal polyposis of the stomach. Additional outcomes are Helicobacter pylori (HP) infection, treatment with proton pump inhibitors (PPI), and colonoscopic examination and abdominal imaging examination, as they are important factors in the therapeutic decision. Methods: We performed a systematic review of the articles published in PubMed and Google Scholar, according to the PRISMA 2020 criteria. Results: We obtained 24 studies that included 83 patients diagnosed with GAPPS, of which 42 underwent prophylactic gastrectomy, 24 benefited from endoscopic follow-up, and 17 were diagnosed with gastric cancer at the first gastroscopic examination. In the prophylactic gastrectomy specimens, malignant gastric disease was confirmed in 10% of cases. GAPPS has been diagnosed more frequently in women. Conclusions: So far, the specialized literature includes a limited number of patients diagnosed with GAPPS. There are also no guidelines yet for the diagnosis and treatment of these patients. Prophylactic gastrectomy or endoscopic surveillance are the only options for patients diagnosed with GAPPS without gastric cancer at the initial examination. For prophylactic gastrectomy, the robotic and laparoscopic approach was preferred. For establishing appropriate lymphadenectomy in prophylactic gastrectomy, future research on gastrectomy specimens is necessary. Most of the included studies were deficient in terms of postoperative follow-up of patients. Thus, we consider it useful to include these patients in a single database. For a comprehensive examination of these and making an appropriate therapeutic decision, we consider it necessary to perform a colonoscopic evaluation, take abdominal imaging, and determine the Helicobacter pylori infection status.

[Prophylactic gastrectomy]

One to 3% of gastric cancers are secondary to genetic predisposition, notably hereditary diffuse gastric cancers (HDGC) caused by CDH1 gene mutations. According to French recommendations, in case of CDH1 gene mutation, a prophylactic total gastrectomy should be performed between 20 and 30 years old. This gastrectomy should remove all the gastric mucosa at both extremities (duodenal and esophageal sides). Histopathological examinations of prophylactic total gastrectomies in asymptomatic CDH1-mutated patients reveal microscopic foci of diffuse-type cancer in 90 to 100% of cases. Lymph node involvement and lympho-vascular invasion are extremely rare, justifying the use of a D1-only lymphadenectomy. In the context of prophylaxis, limited lymphadenectomy and the development of minimally invasive oesogastric surgery, the minimally invasive approach might be the preferred approach, in expert centers. Surgical outcomes seem to be similar to those after gastrectomy for cancer. Prophylactic total gastrectomy is the cornerstone of CGDH management, associated with multidisciplinary follow-up and mammary surveillance in women.

Gastric polyposis and risk of gastric cancer in patients with familial adenomatous polyposis

BACKGROUND

Gastric polyposis is common in familial adenomatous polyposis (FAP) syndrome. However, the incidence and risk factors for gastric cancer (GC) are unclear. We aimed to evaluate the incidence of GC and associated risk factors in a large FAP population.

METHODS

Retrospective review of patients with FAP undergoing upper endoscopy at Mayo Clinic from 1989 to 2023. Cumulative incidence of GC (95% CIs) were calculated using Kaplan-Meier survival approaches. Associations of clinical characteristics with development of GC were examined using Cox proportional hazards regression.

RESULTS

A total of 337 patients underwent 2502 endoscopies with a median of 10.4 years (IQR, 3.9-17.2) of endoscopic surveillance. At any time during surveillance, 294 patients (87%) had gastric polyps; 200 (59%), fundic gland polyps; 116 (34%), low-grade dysplasia (LGD); and 11 (3.3%), high-grade dysplasia (HGD). Among these, only 6 patients (2%) developed GC-5 with HGD (3 [50%] on previous endoscopy and 2 [33%] at the time of cancer diagnosis) and 1 (16%) with LGD on previous endoscopy. The 10-year cumulative incidence of GC is 0% with no polyps, 1% with polyps, 6% with LGD, 11% with polyps ≥2 cm, and 20% with HGD. Both HGD and polyps ≥2 cm had a strong association with the development of GC (P < .001).

CONCLUSION

Although the overall risk of GC in FAP is low, outcomes remain poor. GC can be predicted by endoscopic findings and specific GC surveillance guidelines are imperative to improve detection rates and guide timely intervention.

A case of an unreported point mutation in promoter 1B of the adenomatous polyposis coli gene, which is responsible for gastric adenocarcinoma and proximal polyposis of the stomach

A 35-year-old woman of Asian descent with epigastralgia was referred to our hospital. Esophagogastroduodenoscopy revealed gastric cancer in the upper body and carpeting fundic gland polyposis in the fornix and body. Computed tomography revealed no metastases. Total colonoscopy and capsule endoscopy revealed no polyposis, except in the stomach. The patient was diagnosed with advanced gastric cancer and underwent open total gastrectomy. We speculated that her gastric cancer was a hereditary tumor due to its early onset and accompanying fundic gland polyposis. Germline multi-gene panel testing identified a single-nucleotide variant, c.-191 T > G, in exon 1B of the adenomatous polyposis coli gene, which can cause gastric adenocarcinoma and proximal polyposis of the stomach. To our knowledge, this is the first manuscript to report the variant (c.-191 T > G) in promoter 1B of the adenomatous polyposis coli gene, which is related to a predisposition to gastric adenocarcinoma and proximal polyposis of the stomach.

Gastrointestinal manifestations in patients with gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS): a systematic review with analysis of individual patient data

BACKGROUND AND AIM

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is an autosomal dominant syndrome characterized by fundic gland polyps (FGP) as well as an increased risk of gastric cancer. The syndrome has been recognized as a clinical entity for less than a decade. A clinical suspicion may be complex and can vary from incidental findings of FGPs at gastroscopy to obstructive symptoms with dyspepsia and vomiting. The diagnosis is established by genetic detection of a pathogenic variant in the promotor 1B region of the APC gene. As of yet there are no established clinical criteria for the diagnosis. To increase knowledge of the condition and to discuss possible genetic testing and surveillance strategies, we performed a systematic review of all reported patients with GAPPS.

METHODS

This review was organized according to PRISMA guidelines. The search, which was conducted on September 7th, 2023, was applied to MEDLINE and restricted to only humans and papers in the English language. Only the studies on patients/families with GAPPS verified by identification of a pathogenic variant in the APC promoter 1B were included.

RESULTS

Twelve publications with a total of 113 patients were identified. In all instances the diagnosis was genetically verified with reports of four different variants within the APC promotor 1B region. Eighty-eight patients (90.1%) had gastric polyps, of these seven patients had low-grade dysplasia and five patients had both low- and high-grade dysplasia. Thirty-seven patients (45.7%) underwent gastrectomy. There were no reports of duodenal polyps (0%). Gastric cancer was found in 31 patients (30.1%) with a median age of 48 years (range 19-75). Twenty-six patients died (23.2%) of which 19 had developed gastric cancer (73.1%). One patient was diagnosed with metastatic colorectal cancer (2.2%) and died at 73 years of age. Nineteen patients had colorectal manifestations with < 20 polyps (41.3%).

CONCLUSION

Patients with a pathogenic variant in the APC promoter 1B region have an increased risk of gastric polyposis and early-onset gastric cancer. However, there is considerable variation in clinical expression and penetrance, which makes decisions on surveillance and the timing of prophylactic gastrectomy challenging.

Hereditary Gastrointestinal Tumor Syndromes: When Risk Comes with Your Genes

Despite recent campaigns for screening and the latest advances in cancer therapy and molecular biology, gastrointestinal (GI) neoplasms remain among the most frequent and lethal human tumors. Most GI neoplasms are sporadic, but there are some well-known familial syndromes associated with a significant risk of developing both benign and malignant GI tumors. Although some of these entities were described more than a century ago based on clinical grounds, the increasing molecular information obtained with high-throughput techniques has shed light on the pathogenesis of several of them. The vast amount of information gained from next-generation sequencing has led to the identification of some high-risk genetic variants, although others remain to be discovered. The opportunity for genetic assessment and counseling in these families has dramatically changed the management of these syndromes, though it has also resulted in significant psychological distress for the affected patients, especially those with indeterminate variants. Herein, we aim to summarize the most relevant hereditary cancer syndromes involving the stomach and colon, with an emphasis on new molecular findings, novel entities, and recent changes in the management of these patients.

Consideration of a Novel Surgical Approach in the Management of Gastric Adenocarcinoma and Proximal Polyposis Syndrome

Investigators at MSKCC highlight a novel surgical approach to manage GAPPS.

Upper Gastrointestinal Cancers and the Role of Genetic Testing

Beyond the few established hereditary cancer syndromes with an upper gastrointestinal cancer component, there is increasing recognition of the contribution of novel pathogenic germline variants (gPVs) to upper gastrointestinal carcinogenesis. The detection of gPVs has potential implications for novel treatment approaches of the index cancer patient as well as long-term implications for surveillance and risk-reducing measures for cancer survivors and far-reaching implications for the patients' family. With widespread availability of multigene panel testing, new associations may be identified with germline-somatic integration being critical to determining true causality of novel gPVs. Comprehensive cancer care should incorporate both somatic and germline testing.

Gastric fundic gland polyposis and cancer development after eradication of Helicobacter pylori in patient with gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS)

A 44-year-old woman with gastric cancer (GC) and fundic gland polyposis (FGPs) was referred to our hospital for further diagnosis and treatment. She successfully underwent eradication therapy for Helicobacter pylori (HP) 6 years ago, but did not exhibit FGPs at that time. When she underwent an esophagogastroduodenoscopy 2, 4, and 5 years after the eradication of HP, her imaging results revealed the existence of FGPs which gradually increased in her gastric fundus and body. Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) was suspected and a mutational analysis was performed, revealing an APC promoter 1B variant c.-191T > C. A robotic total gastrectomy with lymphadenectomy was performed. Histopathological analysis of the surgical specimens revealed GC with no lymph node metastasis. GAPPS is characterized by GC and FGPs. However, our case shows different gastric phenotypes that are dependent on the status of HP infection.

Pathology of Gastrointestinal Polyposis Disorders

Gastrointestinal polyposis disorders are a group of syndromes defined by clinicopathologic features that include the predominant histologic type of colorectal polyp and specific inherited gene mutations. Adenomatous polyposis syndromes comprise the prototypical familial adenomatous polyposis syndrome and other recently identified genetic conditions inherited in a dominant or recessive manner. Serrated polyposis syndrome is defined by arbitrary clinical criteria. The diagnosis of hamartomatous polyposis syndromes can be suggested from the histologic characteristics of colorectal polyps and the association with various extraintestinal manifestations. Proper identification of affected individuals is important due to an increased risk of gastrointestinal and extragastrointestinal cancers.

Use of multi-gene panels in patients at high risk of hereditary digestive cancer: position statement of AEG, SEOM, AEGH and IMPaCT-GENÓMICA consortium

This position statement, sponsored by the Asociación Española de Gastroenterología, the Sociedad Española de Oncología Médica, the Asociación Española de Genética Humana and the IMPaCT-Genómica Consortium aims to establish recommendations for use of multi-gene panel testing in patients at high risk of hereditary gastrointestinal and pancreatic cancer. To rate the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We reached a consensus among experts using a Delphi method. The document includes recommendations on clinical scenarios where multi-gene panel testing is recommended in colorectal cancer, polyposis syndromes, gastric and pancreatic cancer, as well as the genes to be considered in each clinical scenario. Recommendations on the evaluation of mosaicisms, counseling strategies in the absence of an index subject and, finally, constitutional analysis after identification of pathogenic tumor variants are also made.

Solving Missing Heritability in Patients With Familial Adenomatous Polyposis With DNA-RNA Paired Testing

PURPOSE

Patients with germline pathogenic variants (PVs) in APC develop tens (attenuated familial adenomatous polyposis [AFAP]) to innumerable (classic FAP) adenomatous polyps in their colon and are at significantly increased lifetime risk of colorectal cancer. Up to 10% of FAP and up to 50% of patients with AFAP who have undergone DNA-only multigene panel testing (MGPT) do not have an identified PV in APC. We seek to demonstrate how the addition of RNA sequencing run concurrently with DNA can improve detection of germline PVs in individuals with a clinical presentation of AFAP/FAP.

METHODS

We performed a retrospective query of individuals tested with paired DNA-RNA MGPT from 2021 to 2022 at a single laboratory and included those with a novel APC PV located in intronic regions infrequently covered by MGPT, a personal history of polyposis, and family medical history provided. All clinical data were deidentified in this institutional review board-exempt study.

RESULTS

Three novel APC variants were identified in six families and were shown to cause aberrant splicing because of the creation of a deep intronic cryptic splice site that leads to an RNA transcript subject nonsense-mediated decay. Several carriers had previously undergone DNA-only genetic testing and had received a negative result.

CONCLUSION

Here, we describe how paired DNA-RNA MGPT can be used to solve missing heritability in FAP families, which can have important implications in family planning and treatment decisions for patients and their families.

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.

NCAD v1.0: a database for non-coding variant annotation and interpretation

The application of whole genome sequencing is expanding in clinical diagnostics across various genetic disorders, and the significance of non-coding variants in penetrant diseases is increasingly being demonstrated. Therefore, it is urgent to improve the diagnostic yield by exploring the pathogenic mechanisms of variants in non-coding regions. However, the interpretation of non-coding variants remains a significant challenge, due to the complex functional regulatory mechanisms of non-coding regions and the current limitations of available databases and tools. Hence, we develop the non-coding variant annotation database (NCAD, http://www.ncawdb.net/), encompassing comprehensive insights into 665,679,194 variants, regulatory elements, and element interaction details. Integrating data from 96 sources, spanning both GRCh37 and GRCh38 versions, NCAD v1.0 provides vital information to support the genetic diagnosis of non-coding variants, including allele frequencies of 12 diverse populations, with a particular focus on the population frequency information for 230,235,698 variants in 20,964 Chinese individuals. Moreover, it offers prediction scores for variant functionality, five categories of regulatory elements, and four types of non-coding RNAs. With its rich data and comprehensive coverage, NCAD serves as a valuable platform, empowering researchers and clinicians with profound insights into non-coding regulatory mechanisms while facilitating the interpretation of non-coding variants.

Differential Diagnoses and Management Approaches for Gastric Polyposis

Multiple gastric polyps are observed in various polyposis syndromes and conditions associated with polypoid lesion development in the stomach. Polyposis syndromes often occur concurrently with specific malignant tumors and can manifest at any point in an individual’s lifespan, thus explaining the diversity in surveillance methods. Furthermore, genetic counseling and surveillance are essential not only for the patients themselves but also for their blood relatives. Therefore, the accurate diagnosis and appropriate surveillance of multiple gastric polyps are crucial for improving patient outcomes. This review aims to provide essential information on such lesions along with representative endoscopic images of familial adenomatous polyposis, Peutz-Jeghers syndrome, Cowden syndrome, Cronkhite-Canada syndrome, juvenile polyposis syndrome, gastric adenocarcinoma and proximal polyposis of the stomach, neuroendocrine tumors in autoimmune gastritis, proton pump inhibitor-related gastric mucosal changes, and multiple submucosal heterotopic glands. We wish for this review to serve as a valuable resource for endoscopists seeking to deepen their comprehension of gastric polyposis.

Early-onset gasrtric cancer (review)

Objective. Early-onset gastric cancer (EOGC) constitutes a serious medical and social problem. Early-onset gastric cancer accounts for approximately 6% of all malignant epithelial neoplasms.

Material and Methods. We reviewed retrospective and prospective randomized trials using Medline and Elibrary databases.

Results. The applied significance of the molecular genetic classifications consist in the formation of groups for evaluating prognosis of the disease using multifactorial analysis. This classification indicates that EOGC diagnosed at a locally advanced stage and primary dissemination is most often caused by GS (TCGA) and MSS/EMT(ACRG) subtypes and is characterized by mutations in CDH1, RhoA, CLDN18-ARHGAP genes. These changes are accompanied by the prevalence of diffuse histological type of gastric cancer according to the Lauren classification and ulcerated or infiltrative type according to the Borrmann classification (type III and IV) with the presence of high-grade adenocarcinoma with a signet ring cell component.

Conclusion. Considering the aggressiveness of gastric cancer in young patients, who more frequently present with locally advanced and metastatic disease at the time of diagnosis, there is a need for increased cancer alertness among physicians of other specialties, early endoscopic controls to detect cancer at early stages and benefit from both surgical and multimodal treatment.

Environmental and Genetic Risk Factors for Gastric Cancer

Gastric cancer is a heterogeneous and prevalent disease. The traditional environmental exposures associated with elevated risk of gastric cancer are less prevalent in the USA today. Genetic risks and risks associated with inflammation remain. Most cases are sporadic, and familial clustering is observed in about 10% of the cases. Hereditary gastric cancer accounts for a very low percentage of cases. Here we review the genetic and environmental risk factors associated with the disease. In addition, we will review screening guidelines and current modalities that are available for screening in high-risk populations.

Attenuated Familial Adenomatous Polyposis

A 36-year-old man was diagnosed with multiple gastric polyps by esophagogastroduodenoscopy. Subsequent colonoscopy identified two tubular adenomas, and computed tomography revealed subcutaneous tumors. Based on these findings, we suspected that gastric polyposis was associated with the APC gene, either attenuated familial adenomatous polyposis (AFAP) or gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). A genetic analysis demonstrated that he had a frameshift variant at codon 1928 of APC, suggesting AFAP. In this era of less Helicobacter pylori infection and frequent use of proton pump inhibitors, diagnoses of AFAP and GAPPS should be considered in patients with prominent gastric fundic gland polyposis.

The comprehensive review of gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) from diagnosis and treatment

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) was first proposed by Wothley et al. in 2012 as a rare familial gastric cancer syndrome associated with an autosomal dominant form of inheritance. GAPPS is characterized by gastric basal gland polyposis from the hilum to the body of the stomach. Li et al. in 2016 showed that the cause of the disease is a point mutation in the promotor 1B region of the APC gene, and genetic testing was used to confirm the diagnosis. If the patient has already developed gastric cancer, treatment should be based on the usual treatment for gastric cancer. If no distant metastases exist, a good prognosis can be expected by performing a total gastrectomy. On the other hand, patients with distant metastasis have a poor prognosis. In the case of dysplasia, prophylactic total gastrectomy is recommended, but because it is highly invasive and postoperative postgastrectomy syndrome must be considered, the decision should be made with careful consideration of the patient's background. Therefore, there are no guidelines for screening for GAPPS, the timing of prophylactic total gastrectomy, or methods of endoscopic surveillance. Because GAPPS is a rare disease, its natural history is still unclear. Further case series are needed to elucidate the molecular biology and clinicopathological features of GAPPS and to establish clinical management, including diagnosis, treatment, and surveillance. In this review, we provide an overview of GAPPS, its clinical management, and its problems, which will be useful for the treatment of GAPPS.

Hereditary Gastric Cancer: Single-Gene or Multigene Panel Testing? A Mono-Institutional Experience

Gastric cancer (GC) has long been a 'Cinderella' among hereditary cancers. Until recently, single-gene testing (SGT) was the only approach to identify high-risk individuals. With the spread of multigene panel testing (MGPT), a debate arose on the involvement of other genes, particularly those pertaining to homologous recombination (HR) repair. We report our mono-institutional experience in genetic counseling and SGT for 54 GC patients, with the detection of nine pathogenic variants (PVs) (9/54:16.7%). Seven out of fifty (14%) patients who underwent SGT for unknown mutations were carriers of a PV in CDH1 (n = 3), BRCA2 (n = 2), BRCA1 (n = 1), and MSH2 (n = 1), while one patient (2%) carried two variants of unknown significance (VUSs). CDH1 and MSH2 emerged as genes involved in early-onset diffuse and later-onset intestinal GCs, respectively. We additionally conducted MGPT on 37 patients, identifying five PVs (13.5%), including three (3/5:60%) in an HR gene (BRCA2, ATM, RAD51D) and at least one VUS in 13 patients (35.1%). Comparing PV carriers and non-carriers, we observed a statistically significant difference in PVs between patients with and without family history of GC (p-value: 0.045) or Lynch-related tumors (p-value: 0.036). Genetic counseling remains central to GC risk assessment. MGPT appeared advantageous in patients with unspecific phenotypes, although it led to challenging results.

Early-Onset GI Cancers: Rising Trends, Genetic Risks, Novel Strategies, and Special Considerations

Cancers in young adults (commonly described as early-onset [EO] cancer) represent a group of malignancies that have unique and challenging biology and genetic, treatment, social, and psychological implications. Even more concerning is a rising trend of EO cancers in multiple tumor types. Research and investigation in EO cancers will help elucidate mechanisms of carcinogenesis, differences in biology and response to treatment, and the need for multidisciplinary care to ensure comprehensive treatment and support for young patients.

Hereditary Cancer Syndromes: A Comprehensive Review with a Visual Tool

Hereditary cancer syndromes account for nearly 10% of cancers even though they are often underdiagnosed. Finding a pathogenic gene variant could have dramatic implications in terms of pharmacologic treatments, tailored preventive programs, and familiar cascade testing. However, diagnosing a hereditary cancer syndrome could be challenging because of a lack of validated testing criteria or because of their suboptimal performance. In addition, many clinicians are not sufficiently well trained to identify and select patients that could benefit from a genetic test. Herein, we searched the available literature to comprehensively review and categorize hereditary cancer syndromes affecting adults with the aim of helping clinicians in their daily clinical practice through a visual tool.

Controlling Gastric Cancer in a World of Heterogeneous Risk

Gastric cancer (GC) is a leading cause of global mortality but also a cancer whose footprint is highly unequal. This review aims to define global disease epidemiology, critically appraise strategies of prevention and disease attenuation, and assess how these strategies could be applied to improve outcomes from GC in a world of variable risk and disease burden. Strategies of primary prevention focus on improving the detection and eradication of the main environmental risk factor, Helicobacter pylori. In certain countries of high incidence, endoscopic or radiographic screening of the asymptomatic general population has been adopted as a means of secondary prevention. By contrast, identification and targeted surveillance of individuals with precancerous lesions (such as intestinal metaplasia) is being increasingly embraced in nations of low incidence. This review also highlights existing knowledge gaps in GC prevention as well as the role of emerging technologies for early detection and risk stratification.

Early-Onset Cancer in the Gastrointestinal Tract Is on the Rise-Evidence and Implications

Epidemiologic data indicate a significant increase in the incidence of colorectal cancer in younger populations in the past three decades. Moreover, recent evidence also demonstrates a similar trend in gastric, pancreatic, and biliary tract cancers. A majority of these early-onset cases are sporadic and lack hereditary or familial background, implying a potential key role for behavioral, lifestyle, nutritional, microbial, and environmental factors. This review explores the current data on early-onset gastrointestinal cancer, exploring the etiology, unique treatment considerations for this population, future challenges, as well as implications for research and practice.

SIGNIFICANCE

The worrisome trend of an increasing incidence of early-onset gastrointestinal cancers appears to be correlated with nonhereditary etiologies in which behavioral, lifestyle, nutritional, microbial, and environmental factors, as well as host mechanisms, may play a key role. Further epidemiologic and pathogenetic research is urgently needed to better understand the underlying mechanisms and to develop preventive strategies and tailored early detection. Young patients with gastrointestinal cancer face unique challenges and unmet needs. These must be addressed in the future management of the disease to minimize treatment-related somatic morbidity and prevent psychosocial sequelae.

Genetic Predisposition to Colorectal Cancer: How Many and Which Genes to Test?

Colorectal cancer is one of the most common tumors, and genetic predisposition is one of the key risk factors in the development of this malignancy. Lynch syndrome and familial adenomatous polyposis are the best-known genetic diseases associated with hereditary colorectal cancer. However, some other genetic disorders confer an increased risk of colorectal cancer, such as Li-Fraumeni syndrome (TP53 gene), MUTYH-associated polyposis (MUTYH gene), Peutz-Jeghers syndrome (STK11 gene), Cowden syndrome (PTEN gene), and juvenile polyposis syndrome (BMPR1A and SMAD4 genes). Moreover, the recent advances in molecular techniques, in particular Next-Generation Sequencing, have led to the identification of many new genes involved in the predisposition to colorectal cancers, such as RPS20, POLE, POLD1, AXIN2, NTHL1, MSH3, RNF43 and GREM1. In this review, we summarized the past and more recent findings in the field of cancer predisposition genes, with insights into the role of the encoded proteins and into the associated genetic disorders. Furthermore, we discussed the possible clinical utility of genetic testing in terms of prevention protocols and therapeutic approaches.

Predictive biomarkers in gastric cancer

Predictive biomarkers are the mainstay of precision medicine. This review summarizes the advancements in tissue-based diagnostic biomarkers for gastric cancer, which is considered the leading cause of cancer-related deaths worldwide. A disease seen in the elderly, it is often diagnosed at an advanced stage, thereby limiting therapeutic options. In Western countries, neoadjuvant/perioperative (radio-)chemotherapy is administered, and adjuvant chemotherapy is administered in the East. The morpho-molecular classification of gastric cancer has opened novel avenues identifying Epstein-Barr-Virus (EBV)-positive, microsatellite instable, genomically stable and chromosomal instable gastric cancers. In chromosomal instable tumors, receptor tyrosine kinases (RKTs) (e.g., EGFR, FGFR2, HER2, and MET) are frequently overexpressed. Gastric cancers such as microsatellite instable and EBV-positive types often express immune checkpoint molecules, such as PD-L1 and VISTA. Genomically stable tumors show alterations in claudin 18.2. Next-generation sequencing is increasingly being used to search for druggable targets in advanced palliative settings. However, most tissue-based biomarkers of gastric cancer carry the risk of a sampling error due to intratumoral heterogeneity, and adequate tissue sampling is of paramount importance.

Genotype-phenotype correlation of small-intestinal polyps on small-bowel capsule endoscopy in familial adenomatous polyposis

BACKGROUND AND AIMS

In familial adenomatous polyposis (FAP), neoplastic lesions outside the colon have become increasingly important. The genotype-phenotype correlation has been established for duodenal polyps, and regular screening is recommended. However, this correlation remains unclear for small-intestinal lesions, except for reports on the relationship between their occurrence and Spigelman stage. Here, we used small-bowel capsule endoscopy (SBCE) to investigate the genotype-phenotype correlation of small-intestinal polyps in FAP.

METHODS

The genotype-phenotype correlation of small-intestinal polyps was investigated in patients with FAP who underwent SBCE, Esophagogastroduodenoscopy (EGD), and adenomatous polyposis coli (APC) gene analysis. Of 64 patients with FAP who underwent SBCE, 41 were included in the final analysis, 4 did not undergo a complete small intestine examination, and 19 did not undergo genetic analysis.

RESULTS

The prevalence (median number) of small-intestinal polyps by Spigelman stage was 26% (1.5), 0% (0), 44% (5), 60% (4), and 73% (25.5) for stages 0 to IV, respectively. Significantly more small-intestinal polyps were found in Spigelman stage III and IV groups than in the stage 0 group (P < .05). The APC variant was negative for 6 patients (15%), and the sites associated with more than 5 small-intestinal polyps were codons 278, 1062, 1114, 1281, 1307, 1314, and 1504.

CONCLUSIONS

In FAP patients, SBCE surveillance is potentially recommended for patients with pathogenic variants in the APC gene at codons 278 and 1062 to 1504 or with Spigelman stage III or higher.

Gastric Cancer Risk and Pathogenesis in BRCA1 and BRCA2 Carriers

Carriers of a pathogenic germline variant (PV) in BRCA1 or BRCA2 are at increased risk for a number of malignancies, including breast, ovarian, pancreatic, and prostate cancer. In this review, we discuss emerging evidence that BRCA2 PV carriers, and likely also BRCA1 PV carriers, are also at increased risk for gastric cancer (GC), highlighting that GC may be part of the BRCA1/2 cancer risk spectrum. While the pathogenesis of GC among BRCA1/2 PV carriers remains unclear, increasing evidence reveals that GCs are often enriched with mutations in homologous recombination-associated genes such as BRCA1/2, and that GC prognosis and response to certain therapies can depend on BRCA1/2 expression. Given the strength of data published to date, a risk management strategy for GC among BRCA1/2 PV carriers is needed, and herein we also propose a potential strategy for GC risk management in this population. Moving forward, further study is clearly warranted to define the mechanistic relationship between BRCA1/2 PVs and development of GC as well as to determine how GC risk management should be factored into the clinical care of BRCA1/2 carriers.

Endoscopic Surveillance in Patients with the Highest Risk of Gastric Cancer: Challenges and Solutions

Gastric cancer is one of the most significant causes of cancer-related morbidity and mortality worldwide. Recognized modifiable risk factors include Helicobacter pylori infection, geographic location, select dietary factors, tobacco use and alcohol consumption. In addition, multiple hereditary cancer predisposition syndromes are associated with significantly elevated gastric cancer risk. Endoscopic surveillance in hereditary gastric cancer predisposition syndromes has the potential to identify gastric cancer at earlier and more treatable stages, as well as to prevent development of gastric cancer through identification of precancerous lesions. However, much uncertainty remains regarding use of endoscopic surveillance in hereditary gastric cancer predisposition syndromes, including whether or not it should be routinely performed, the surveillance interval and age of initiation, cost-effectiveness, and whether surveillance ultimately improves survival from gastric cancer for these high-risk individuals. In this review, we outline the hereditary gastric cancer predisposition syndromes associated with the highest gastric cancer risks. Additionally, we cover current evidence and guidelines addressing hereditary gastric cancer risk and surveillance in these syndromes, along with current challenges and limitations that emphasize a need for continued research in this field.

Gastric Cancer: Emerging Trends in Prevention, Diagnosis, and Treatment

Gastric adenocarcinoma (GC) is the fourth leading cause of global cancer mortality, and the leading infection-associated cancer. Helicobacter pylori is the dominant risk factor for GC and classified as an IARC class I carcinogen. Surveillance of gastric premalignant conditions is now indicated in high-risk patients. Upper endoscopy is the gold standard for GC diagnosis, and image-enhanced endoscopy increases the detection of gastric premalignant conditions and early gastric cancer (EGC). Clinical staging is crucial for treatment approach, defining early gastric cancer, operable locoregional disease, and advanced GC. Endoscopic submucosal dissection is the treatment of choice for most EGC. Targeted therapies are rapidly evolving, based on biomarkers including MSI/dMMR, HER2, and PD-L1. These advancements in surveillance, diagnostic and therapeutic strategies are expected to improve GC survival rates in the near term.

Environmental and genetic risk factors for gastric cancer

Gastric cancer is a heterogeneous and prevalent disease. The traditional environmental exposures associated with an elevated risk of gastric cancer are less prevalent in the United States today. Genetic risks and risks associated with inflammation remain. Most cases are sporadic and familial clustering is observed in about 10% of the cases. Hereditary gastric cancer accounts for a very low percentage of cases. Here we review the genetic and environmental risk factors associated with the disease.

CAST as a Potential Oncogene, Identified by Machine Search, in Gastric Cancer Infiltrated with Macrophages and Associated with Lgr5

Background: Gastric cancer (GC) is one of the leading malignant diseases worldwide, especially in Asia. CAST is a potential oncogene in GC carcinogenesis. The character of macrophage infiltration in the GC microenvironment also remains unaddressed. Methods: We first applied machine searching to evaluate gene candidates for GC. CAST expression and pan-cancer surveyance were analyzed using the Human Protein Atlas (HPA) and Gene Expression Profiling Interactive Analysis 2 (GEPIA2) database. The protein–protein interaction (PPI) network was downloaded from STRING. We investigated the impact of CAST on clinical prognosis using a Kaplan–Meier plotter. The correlations between CAST and Lgr5 and macrophage infiltration in GC were determined using TIMER 2.0. Finally, GeneMANIA was also used to evaluate the possible functional linkages between genes. Results: After the machine-assisted search, CAST expression was found to significantly influence the overall survival of GC patients. STRING revealed CAST-related proteomic and transcriptomic associations, mainly concerning the CAPN family. Moreover, CAST significantly impacts the prognosis of GC based on the validation of other datasets. Notably, high CAST expression was correlated with worse overall survival in GC patients (hazard ratio = 1.59; log-rank P = 9.4 × 10−8). CAST and Lgr5 expression were both positively correlated with WNT 2 and WNT 2B. Among the GC patients in several datasets, CAST and macrophage infiltration, evaluated together, showed no obvious association with poor clinical overall survival. Conclusions: CAST plays an important role in the clinical prognosis of GC and is associated with WNT 2/WNT 2B/Lgr5. Our study demonstrates that CAST’s influence on overall survival in GC is regulated by macrophage infiltration.

Familial and hereditary gastric cancer, an overview

There are three major hereditable syndromes that affect primarily the stomach: hereditary diffuse gastric cancer (HDGC), gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) and familial intestinal gastric cancer (FIGC). HDGC is caused by germline mutations in CDH1 gene that occur in 10-40% of HDGC families and, in a minority of cases, by mutations in CTNNA1 gene. GAPPS is caused by germline mutations in the promoter 1B of APC gene, and the genetic cause of FIGC is not fully elucidated. Gastric cancer can also be observed as part of other inherited cancer disorders, namely in familial adenomatous polyposis, MUTYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, Lynch syndrome, Li-Fraumeni syndrome, Cowden syndrome, and hereditary breast and ovarian cancer syndrome. In this article, the state of the art of familial gastric cancer regarding the clinical, molecular and pathology features is reviewed, as well as the practical aspects for a correct diagnosis and clinical management.

Four cases of gastric adenocarcinoma and proximal polyposis of the stomach treated by robotic total gastrectomy

Background

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is a rare disease and characterized by a unique point mutation in the promoter 1B region of the adenomatous polyposis coli (APC) gene. There are two aims in surgery for GAPPS; the first is prophylactic gastrectomy, and the second is excising concurrent cancer. We performed robotic total gastrectomy (RTG) for four cases of GAPPS.

Case presentation

Case 1 was a woman in her 40 s whose sister had died from gastric cancer. Mutational analysis revealed mutation of APC exon 1B. We performed prophylactic gastrectomy. Case 2 was a woman in her 30 s who had a mutation of APC exon 1B, and preoperative biopsy revealed suspected adenocarcinoma. Case 3 was a woman in her 40 s who was diagnosed with gastric cancer with multiple polyps in the stomach and a mutation of APC exon 1B. Case 4 was a woman in her 20 s in whom biopsy revealed low-grade dysplasia of a raised lesion. She had a mutation in APC exon 1B. We performed RTG with D1 + lymphadenectomy in all patients, and there were no intraoperative complications.

Conclusions

Patients with GAPPS are mainly followed regularly with repeat biopsy, and tumors are detected in an early stage. As the safety of robotic surgery for the early gastric cancer is reported, RTG is an option for these patients. This is the first report of RTG for GAPPS patients.

Progress in Metabolic Studies of Gastric Cancer and Therapeutic Implications

Background:

Worldwide, gastric cancer is ranked the fifth malignancy in incidence and the third malignancy in mortality. Gastric cancer causes an altered metabolism that can be therapeutically exploited.

Objective:

To provide an overview of the significant metabolic alterations caused by gastric cancer and propose a blockade.

Methods:

A comprehensive and up-to-date review of descriptive and experimental publications on the metabolic alterations caused by gastric cancer and their blockade. This is not a systematic review.

Results:

Gastric cancer causes high rates of glycolysis and glutaminolysis. There are increased rates of de novo fatty acid synthesis and cholesterol synthesis. Moreover, gastric cancer causes high rates of lipid turnover via fatty acid -oxidation. Preclinical data indicate that the individual blockade of these pathways via enzyme targeting leads to antitumor effects in vitro and in vivo. Nevertheless, there is no data on the simultaneous blockade of these five pathways, which is critical, as tumors show metabolic flexibility in response to the availability of nutrients. This means tumors may activate alternate routes when one or more are inhibited. We hypothesize there is a need to simultaneously blockade them to avoid or decrease the metabolic flexibility that may lead to treatment resistance.

Conclusions:

There is a need to explore the preclinical efficacy and feasibility of combined metabolic therapy targeting the pathways of glucose, glutamine, fatty acid synthesis, cholesterol synthesis, and fatty acid oxidation. This may have therapeutical implications because we have clinically available drugs that target these pathways in gastric cancer.

Hereditary Diffuse Gastric Cancer—Update Based on the Current Consort Recommendations

Hereditary diffuse gastric cancer (HDGC) is an autosomal dominant inherited cancer syndrome that has been associated with a mutation of the CDH1, and rarely the CTNNA1 gene, respectively. HDGC is characterized histologically by multifocal growth and signet ring cells in the gastric mucosa and lobular type breast cancer. In cases of a proven pathogenic CDH1 mutation, a prophylactic gastrectomy, or alternatively, an annual surveillance gastroscopy in expert centers is recommended. Additionally, MR imaging of the breast should be performed annually starting from the age of 30, to detect lobular breast cancer. In 2020, the International Gastric Cancer Linkage Consortium (IGCLC) additionally defined new clinical groups with specific recommendations: (1) the group of patients with a proven mutation in the CDH1 gene, but exclusive manifestation as lobular breast cancer, was defined as hereditary lobular breast cancer (HLBC); (2) the group, which clinically fulfills familial HDGC criteria, in the absence of a relevant mutation, was designated as HDGC-like. This update summarizes relevant aspects of hereditary gastric cancer and the current recommendation criteria of the IGCLC published in 2020.

Filling in the "GAPPS": an unusual presentation of a child with gastric adenocarcinoma and proximal polyposis of the stomach

Gastric Adenocarcinoma and Proximal Polyposis of the Stomach (GAPPS) is a very rare gastric polyposis syndrome characterized by numerous polyps of the gastric fundus and body. We present the unusual case of a 10-year-old Polish-American male with history of eosinophilic esophagitis, who was found to have multiple fundic gland polyps (FGP) with low grade dysplasia on esophagogastroduodenoscopy. Subsequent evaluation including genetic testing confirmed the diagnosis of GAPPS, and after exhaustive multidisciplinary consultation the decision was made to proceed with prophylactic total gastrectomy given the markedly increased risk of gastric adenocarcinoma in GAPPS patients. To our knowledge, this represents the youngest patient diagnosed with GAPPS and the youngest patient who has undergone prophylactic gastrectomy for this disease at age 8 and 10 years, respectively. The pathophysiology, presentation, and treatment of GAPPS in a pediatric patient are discussed.

Prophylactic laparoscopic total gastrectomy for gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS): the first report in Asia

A 41-year-old woman was admitted to our hospital for epigastralgia. She had been admitted to another hospital for fundic gland polyposis (FGP) without any symptoms, and no malignancy had been noted in her previous endoscopy. However, a biopsy performed at our hospital revealed adenocarcinoma, and computed tomography (CT) revealed multiple liver and peritoneal metastases. We clinically suspected gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) and indicated genetic testing. The point mutation in exon 1B of APC was revealed. She was diagnosed with GAPPS with multiple liver metastases and underwent systemic chemotherapy. She has two older brothers who also have FGP. The same genomic mutation was observed in both brothers and their mother, and they were also diagnosed with GAPPS. The brothers underwent prophylactic laparoscopic total gastrectomy with D1 lymph-node dissection.

Identifying Potential miRNA Biomarkers for Gastric Cancer Diagnosis Using Machine Learning Variable Selection Approach

Aim: This study aimed to accurately identification of potential miRNAs for gastric cancer (GC) diagnosis at the early stages of the disease. Methods: We used GSE106817 data with 2,566 miRNAs to train the machine learning models. We used the Boruta machine learning variable selection approach to identify the strong miRNAs associated with GC in the training sample. We then validated the prediction models in the independent sample GSE113486 data. Finally, an ontological analysis was done on identified miRNAs to eliciting the relevant relationships. Results: Of those 2,874 patients in the training the model, there were 115 (4%) patients with GC. Boruta identified 30 miRNAs as potential biomarkers for GC diagnosis and hsa-miR-1343-3p was at the highest ranking. All of the machine learning algorithms showed that using hsa-miR-1343-3p as a biomarker, GC can be predicted with very high precision (AUC; 100%, sensitivity; 100%, specificity; 100% ROC; 100%, Kappa; 100) using with the cut-off point of 8.2 for hsa-miR-1343-3p. Also, ontological analysis of 30 identified miRNAs approved their strong relationship with cancer associated genes and molecular events. Conclusion: The hsa-miR-1343-3p could be introduced as a valuable target for studies on the GC diagnosis using reliable biomarkers.

Genetic Syndromes Associated with Gastric Cancer

Although environmental factors such as Helicobacter pylori, tobacco, and diet are major contributors to the development of gastric cancer (GC) worldwide, it is estimated that up to 5% to 10% of GC cases are due to an underlying hereditary susceptibility caused by germline pathogenic variants. Hereditary diffuse gastric cancer (HDGC) caused by germline pathogenic variants in the CDH1 gene is the principal familial GC syndrome. However, other well-established hereditary gastrointestinal syndromes have been associated with an increased risk of GC. In this review, we will discuss the latest insights and advances in our understanding of GC associated with Lynch syndrome (LS), familial adenomatous polyposis (FAP), gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS), Li-Fraumeni syndrome (LFS), Peutz-Jeghers syndrome (PJS), and juvenile polyposis syndrome (JPS). We will also discuss the emergence of new associations of the homologous recombination pathway genes (BRCA1, BRCA2) with GC.