Fundic gland polyp dysplasia is common in familial adenomatous polyposis

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.

Management of gastric polyps: an endoscopy-based approach

The endoscopic finding of a gastric polyp and the histopathologic report that follows may leave clinicians with questions that have not been addressed in formal guidelines: do all polyps need to be excised, or can they just be sampled for biopsy? If so, which ones and how many should be sampled? What follow-up evaluation is needed, if any? This review relies on the existing literature and our collective experience to provide practical answers to these questions. Fundic gland polyps, now the most frequent gastric polyps in Western countries because of widespread use of proton pump inhibitors, and hyperplastic polyps, the second most common polyps notable for their association with gastritis and their low but important potential for harboring dysplastic or neoplastic foci, are discussed in greater detail. Adenomas have had their name changed to raised intraepithelial neoplasia and are decreasing in parallel with Helicobacter pylori infection; however, they do retain their importance as harbingers of gastric cancer, particularly in East Asia. Gastrointestinal stromal tumors have low incidence and no known associations, but their malignant potential is high; early diagnosis and proper management are crucial. Although rare and benign, inflammatory fibroid polyps need to recognized, particularly by pathologists, to avoid misdiagnosis. Gastric neuroendocrine tumors (carcinoids) are important because of their association with either atrophic gastritis or the multiple endocrine neoplasia syndromes; those that do not arise in these backgrounds have high malignant potential and require aggressive management. The review concludes with some practical suggestions on how to approach gastric polyps detected at endoscopy.

The growing complexity of the intestinal polyposis syndromes

Familial adenomatous polyposis has been the first form of inherited intestinal polyposis to be recognized. For a long time it has been considered the main polyposis syndrome, associated with an easily recognizable phenotype, with a marginal role attributed to a few very rare hamartomatous conditions. More recently, it has been gradually demonstrated that the intestinal polyposes encompass a range of conditions within a wide spectrum of disease severity, polyp histology, and extraintestinal manifestations. A growing number of genes and phenotypes has been identified, and heterogeneity of somatic molecular pathways underlying epithelial transformation in different syndromes and associated tumors has been documented. Increasing knowledge on the molecular bases and more widespread use of genetic tests has shown phenotypic overlaps between conditions that were previously considered distinct, highlighting diagnostic difficulties. With the advent of next generation sequencing, the diagnosis and the classification of these syndromes will be progressively based more on genetic testing results. However, the phenotypic variability documented among patients with mutations in the same genes cannot be fully explained by different expressivity, indicating a role for as yet unknown modifying factors. Until the latter will be identified, the management of patients with polyposis syndromes should be guided by both clinical and genetic findings.

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.

Risk of colorectal polyps in patients with sporadic gastric polyps: A case-control study

AIM: To assess the risk of colonic polyps, adenomas and advanced neoplastic lesions (ANL) in patients with sporadic gastric polyps, especially those with fundic gland polyps (FGP).

METHODS: Clinical records of patients who had performed an upper and a lower digestive endoscopy between September 2007 and August 2008 were retrospectively analyzed. A case-control study was carried out, calling patients with gastric polyps as “cases” and patients without gastric polyps as “controls”. The risk of colonic polyps, adenomas and ANL (villous component ≥ 25%, size ≥ 10 mm, or high grade dysplasia) was assessed [odds ratio (OR) and its corresponding 95%CI].

RESULTS: Two hundred and forty seven patients were analyzed: 78 with gastric polyps (cases) and 169 without gastric polyps (controls). Among the cases, the majority of gastric polyps were FGP (80%, CI: 69-88) and hyperplastic (20%, CI: 12-31); 25% had colonic polyps (25% hyperplastic and 68% adenomas, from which 45% were ANL). Among the controls, 20% had colonic polyps (31% hyperplastic and 63% adenomas, from which 41% were ANL). The patients with sporadic FGP had an OR of 1.56 (CI: 0.80-3.04) for colonic polyps, an OR of 1.78 (CI: 0.82-3.84) for colonic adenomas, and an OR of 0.80 (CI: 0.21-2.98) for ANL. Similar results were found in patients with gastric polyps in general.

CONCLUSION: The results of this study did not show more risk of colorectal adenomas or ANL neither in patients with sporadic gastric polyps nor in those with FGP.

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.

Gastric stem cells and gastric cancer stem cells

The gastric epithelium is continuously regenerated by gastric stem cells, which give rise to various kinds of daughter cells, including parietal cells, chief cells, surface mucous cells, mucous neck cells, and enteroendocrine cells. The self-renewal and differentiation of gastric stem cells need delicate regulation to maintain the normal physiology of the stomach. Recently, it was hypothesized that cancer stem cells drive the cancer growth and metastasis. In contrast to conventional clonal evolution hypothesis, only cancer stem cells can initiate tumor formation, self-renew, and differentiate into various kinds of daughter cells. Because gastric cancer can originate from gastric stem cells and their self-renewal mechanism can be used by gastric cancer stem cells, we review here how critical signaling pathways, including hedgehog, Wnt, Notch, epidermal growth factor, and bone morphogenetic protein signaling, may regulate the self-renewal and differentiation of gastric stem cells and gastric cancer stem cells. In addition, the precancerous change of the gastric epithelium and the status of isolating gastric cancer stem cells from patients are reviewed.

Key genetic considerations in the management of suspected hereditary colorectal cancer

SUMMARY Hereditary bowel cancer syndromes account for up to 5% of colorectal cancer (CRC) incidence. Presentation of CRC under the age of 50 years should alert clinicians to a possible underlying genetic predisposition. This article focuses on Lynch syndrome (hereditary nonpolyposis CRC). Regular bowel screening is effective in reducing the risk of CRC and improving overall survival in Lynch syndrome families. The issues surrounding the clinical diagnostic criteria and the shortcomings of the referral process are described, and it is questioned whether a universal strategy for diagnosis should be employed. This article summarizes the evidence for the benefit of bowel screening and suggests practical steps to help ensure compliance with screening recommendations. Finally, it is discussed how collaboration between geneticists, gastroenterologists and surgeons can inform surgical decision-making for the benefit of the patient.

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.

Proton pump inhibitors: the good, the bad, and the unwanted

Proton pump inhibitors (PPIs) are one of the most commonly prescribed classes of medications in the United States. By inhibiting gastric H/K adenosine triphosphatase via covalent binding to the cysteine residues of the proton pump, they provide the most potent acid suppression available. Long-term PPI use accounts for the majority of total PPI use. Absolute indications include peptic ulcer disease, chronic nonsteroidal anti-inflammatory drugs use, treatment of Helicobacter pylori, and erosive esophagitis. Although PPIs are generally considered safe, numerous adverse effects, particularly associated with long-term use have been reported. Many patients receiving chronic PPI therapy do not have clear indications for their use, prompting consideration for reduction or discontinuation of their use. This article reviews the indications for PPI use, the adverse effects/risks involved with their use, and conditions in which their use is controversial.

Colorectal carcinoma: Pathologic aspects

Colorectal carcinoma is one of the most common cancers and one of the leading causes of cancer-related death in the United States. Pathologic examination of biopsy, polypectomy and resection specimens is crucial to appropriate patient managemnt, prognosis assessment and family counseling. Molecular testing plays an increasingly important role in the era of personalized medicine. This review article focuses on the histopathology and molecular pathology of colorectal carcinoma and its precursor lesions, with an emphasis on their clinical relevance.

Colorectal carcinoma: Pathologic aspects

Colorectal carcinoma is one of the most common cancers and one of the leading causes of cancer-related death in the United States. Pathologic examination of biopsy, polypectomy and resection specimens is crucial to appropriate patient managemnt, prognosis assessment and family counseling. Molecular testing plays an increasingly important role in the era of personalized medicine. This review article focuses on the histopathology and molecular pathology of colorectal carcinoma and its precursor lesions, with an emphasis on their clinical relevance.

Extra-abdominal desmoid tumors associated with familial adenomatous polyposis

Extra-abdominal desmoid tumors are a significant cause of morbidity in patients with familial adenomatous polyposis syndrome. Understanding of the basic biology and natural history of these tumors has increased substantially over the past decade. Accordingly, medical and surgical management of desmoid tumors has also evolved. This paper analyzes recent evidence pertaining to the epidemiology, molecular biology, histopathology, screening, and treatment of extra-abdominal desmoid tumors associated with familial adenomatous polyposis syndrome.

Gastric tumours in hereditary cancer syndromes: clinical features, molecular biology and strategies for prevention

Gastric cancer is the major cause of cancer-related deaths worldwide. The majority of them are classified as sporadic, whereas the remaining 10% exhibit familial clustering. Hereditary diffuse gastric cancer (HDGC) syndrome is the most important condition that leads to hereditary gastric cancer. However, other hereditary cancer syndromes, such as hereditary non-polyposis colorectal cancer, familial adenomatous polyposis, Peutz-Jeghers syndrome, Li-Fraumeni syndrome and hereditary breast and ovarian cancer, entail a higher risk compared to the general population for developing this kind of neoplasia. In this review, we describe briefly the most important aspects related to clinical features, molecular biology and strategies for prevention in hereditary gastric associated to different cancer syndromes.

Gastric polyps in patients with portal hypertension

OBJECTIVES

Gastric hyperplastic polyps are usually associated with chronic gastritis including Helicobacter pylori gastritis and postantrectomy stomachs. Here, we report on a series of 12 patients with portal hypertension secondary to liver cirrhosis, who were found to have a unique histological type of gastric polyp on endoscopy.

METHODS

Retrospective chart review of 12 patients with portal hypertension, who presented with histologically diagnosed gastric hyperplastic polyps. These polyps were reviewed and compared with hyperplastic polyps from 21 patients who did not have portal hypertension.

RESULTS

The endoscopic appearances of portal hypertension-associated polyps varied considerably, with sizes ranging up to 18 mm. They were sessile or pedunculated, singular or multiple, found in the antrum or body of the stomach, and endoscopically appeared to be typical hyperplastic polyps. Histopathological examination, however, showed mucosal hyperplasia and extensive vascular proliferation and granulation tissue formation.

CONCLUSION

The unique histological appearance of gastric hyperplastic polyps in patients with portal hypertension polyps is described. The exact pathogenetic mechanism of polyp formation is unclear although it seems possible that the underlying cause is mucosal injury that is vascular in nature rather than being secondary to surface inflammation. Although there is an emerging evidence of the neoplastic potential of usual hyperplastic polyps, the natural history of portal hypertension-associated polyps is unknown. Identification and management of portal hypertension-associated gastric polyps present a particular dilemma, as these patients often have coagulopathies and vascular ectasias. Therefore, the natural history and endoscopic features of gastric polyps arising in portal hypertensive patients warrants further exploration.

Hereditary colon cancer syndromes

Colon cancer is associated with a family history in up to 25% of cases. As many as 5% are associated with an established hereditary syndrome, demonstrating the profound influence of inheritable genetic mechanisms in the development of this disease. These syndromes confer a diverse spectrum of risk, age of presentation, endoscopic and histological findings, extracolonic manifestations, and modes of inheritance. As the molecular characteristics of these disorders become better described, enhanced genotype-phenotype correlations may offer a more targeted approach to diagnosis, screening, and surveillance. While the strategies for diagnosis and management of familial adenomatous polyposis (FAP) and Lynch syndrome are more established, the approach to newly recognized syndromes such as MUTYH-associated polyposis (MAP) and hyperplastic polyposis syndromes continues to evolve. Effective cancer prevention in affected individuals and at-risk family members first requires timely recognition of these hereditary colon cancer syndromes followed by integration of genetic testing and clinical examinations.

Modified multivisceral transplantation with spleen-preserving pancreaticoduodenectomy for patients with familial adenomatous polyposis "Gardner's Syndrome"

BACKGROUND

Liver-sparing "modified" multivisceral transplantation (MMVTx) has recently been more used for patients with diffuse gastrointestinal disorders and preserved hepatic functions. Evisceration techniques with preservation of native spleen were also introduced to reduce risk of posttransplant lymphoproliferative disorders. This study focuses on the indications of MMVTx for patients with familial adenomatous polyposis (FAP) and the technical feasibility of performing spleen-preserving pancreaticoduodenectomy (SPPD).

METHODS

Between 1993 and 2009, 10 FAP patients required MMVTx. Nine were adults and one was a child, with a female:male ratio of 1:1.

RESULTS

Short gut with duodenal adenomatosis and extensive desmoid tumors with pancreaticoduodenal involvement dictated need for MMVTx. SPPD was technically feasible in four recipients, and conventional evisceration including splenectomy was performed in remaining six recipients. With an overall cumulative survival of 90% at 1 year and 77% at 10 years, all SPPD recipients were alive with no single example of posttransplant lymphoproliferative disorder, graft-versus-host disease, or chronic rejection. However, SPPD was associated with an increase (P>0.3) in total ischemia time, operative time, and packed red blood cells requirement but with shorter (P=0.6) length of hospital stay. With a mean follow-up of 50±45 months (range 18-128 months), none of the 10 recipients experienced intraabdominal desmoid tumor recurrence or developed de novo visceral allograft neoplasm.

CONCLUSION

MMVTx is a valuable therapeutic option for FAP patients who are in need for visceral transplantation with pathologic involvement of the pancreaticoduodenal complex. SPPD is technically feasible, and efforts should always be made to preserve native spleen because of the reported herein therapeutic advantages.

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.

Prevalência de alterações proliferativas gástricas em pacientes com uso crônico de inibidores de bomba de prótons

RACIONAL: As medicações mais frequentemente prescritas e usadas de forma crônica por pacientes com queixas dispépticas pertencem ao grupo dos inibidores de bomba de prótons cujo principal representante é o omeprazol, utilizado clinicamente a cerca de 20 anos. Estudos recentes têm postulado a relação entre o uso crônico desta medicação e alterações proliferativas macroscópicas e microscópicas da mucosa do fundo e corpo gástrico, principalmente os pólipos de glândulas fúndicas. OBJETIVO: Analisar a frequência e o tipo de alterações proliferativas gástricas em usuários crônicos de inibidores de bomba de prótons e sua associação com idade, dose utilizada, tempo de uso, sintomatologia e infecção pelo Helicobacter pylori. MÉTODO: Estudo transversal de prevalência realizado no Serviço de Endoscopia Digestiva do Hospital de Clínicas da Universidade Federal do Paraná. Aplicado questionário com informações quanto ao uso destas drogas e realizada endoscopia digestiva alta em sujeitos em uso contínuo desta classe de medicamentos há pelo menos 12 meses. Realizadas biópsias de fundo, corpo e antro gástrico em todos os pacientes. Pólipos eram retirados ao serem identificados, para análise histopatológica. Realizada pesquisa do Helicobacter pylori por teste de urease e análise histopatológica. RESULTADOS: Vinte e dois indivíduos foram incluídos sendo que seis (27,3%) apresentaram alterações proliferativas da mucosa oxíntica. Destes, dois (9,1%) apresentavam pólipos fúndicos esporádicos e quatro apresentavam exclusivamente alteração proliferativa microscópica como formação cística glandular. Houve significância estatística (p<0,05) na associação entre idade > 60 anos e estas alterações. Não houve associação entre dose de uso, tempo de uso, sintomatologia e infecção pelo Helicobacter pylori. CONCLUSÕES: Ocorrem alterações proliferativas de mucosa oxíntica em indivíduos em uso crônico de inibidores de bomba de prótons. A associação entre idade e alterações proliferativas apresentou significância estatística.

Hereditary and familial colon cancer

Between 2% to 5% of all colon cancers arise in the setting of well-defined inherited syndromes, including Lynch syndrome, familial adenomatous polyposis, MUTYH-associated polyposis, and certain hamartomatous polyposis conditions. Each is associated with a high risk of colon cancer. In addition to the syndromes, up to one-third of colon cancers exhibit increased familial risk, likely related to inheritance. A number of less penetrant, but possibly more frequent susceptibility genes have been identified for this level of inheritance. Clarification of predisposing genes allows for accurate risk assessment and more precise screening approaches. This review examines the colon cancer syndromes, their genetics and management, and also the common familial colon cancers with current genetic advances and screening guidelines.

Familial adenomatous polyposis

Patients with FAP are guaranteed to have one major abdominal surgery in their life. They are also subject to cancers and benign disorders in other organ systems, some of which can be life threatening. Steering a course through life while avoiding preventable disease and complications of treatment, and maintaining good quality of life is a challenge for health care givers, patients, and their families. A successful voyage calls for clinical cooperation between providers and patients, education and understanding, and expertise and experience. FAP patients and families should be involved in a registry or genetic center, not to the exclusion of local practitioners but to their benefit. In this way the best of care is given and the best of outcomes ensured.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is characterized by the development of many tens to thousands of adenomas in the rectum and colon during the second decade of life. FAP has an incidence at birth of about 1/8,300, it manifests equally in both sexes, and accounts for less than 1% of colorectal cancer (CRC) cases. In the European Union, prevalence has been estimated at 1/11,300-37,600. Most patients are asymptomatic for years until the adenomas are large and numerous, and cause rectal bleeding or even anemia, or cancer develops. Generally, cancers start to develop a decade after the appearance of the polyps. Nonspecific symptoms may include constipation or diarrhea, abdominal pain, palpable abdominal masses and weight loss. FAP may present with some extraintestinal manifestations such as osteomas, dental abnormalities (unerupted teeth, congenital absence of one or more teeth, supernumerary teeth, dentigerous cysts and odontomas), congenital hypertrophy of the retinal pigment epithelium (CHRPE), desmoid tumors, and extracolonic cancers (thyroid, liver, bile ducts and central nervous system). A less aggressive variant of FAP, attenuated FAP (AFAP), is characterized by fewer colorectal adenomatous polyps (usually 10 to 100), later age of adenoma appearance and a lower cancer risk. Some lesions (skull and mandible osteomas, dental abnormalities, and fibromas on the scalp, shoulders, arms and back) are indicative of the Gardner variant of FAP. Classic FAP is inherited in an autosomal dominant manner and results from a germline mutation in the adenomatous polyposis (APC) gene. Most patients (~70%) have a family history of colorectal polyps and cancer. In a subset of individuals, a MUTYH mutation causes a recessively inherited polyposis condition, MUTYH-associated polyposis (MAP), which is characterized by a slightly increased risk of developing CRC and polyps/adenomas in both the upper and lower gastrointestinal tract. Diagnosis is based on a suggestive family history, clinical findings, and large bowel endoscopy or full colonoscopy. Whenever possible, the clinical diagnosis should be confirmed by genetic testing. When the APC mutation in the family has been identified, genetic testing of all first-degree relatives should be performed. Presymptomatic and prenatal (amniocentesis and chorionic villous sampling), and even preimplantation genetic testing is possible. Referral to a geneticist or genetic counselor is mandatory. Differential diagnoses include other disorders causing multiple polyps (such as Peutz-Jeghers syndrome, familial juvenile polyps or hyperplastic polyposis, hereditary mixed polyposis syndromes, and Lynch syndrome). Cancer prevention and maintaining a good quality of life are the main goals of management and regular and systematic follow-up and supportive care should be offered to all patients. By the late teens or early twenties, colorectal cancer prophylactic surgery is advocated. The recommended alternatives are total proctocolectomy and ileoanal pouch or ileorectal anastomosis for AFAP. Duodenal cancer and desmoids are the two main causes of mortality after total colectomy, they need to be identified early and treated. Upper endoscopy is necessary for surveillance to reduce the risk of ampullary and duodenal cancer. Patients with progressive tumors and unresectable disease may respond or stabilize with a combination of cytotoxic chemotherapy and surgery (when possible to perform). Adjunctive therapy with celecoxib has been approved by the US Food and Drug Administration and the European Medicines Agency in patients with FAP. Individuals with FAP carry a 100% risk of CRC; however, this risk is reduced significantly when patients enter a screening-treatment program.

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.

Management of gastric polyps: a pathology-based guide for gastroenterologists

1-4% of patients who undergo gastric biopsy have gastric polyps. These lesions may be true epithelial polyps, heterotopias, lymphoid tissue, or stromal lesions. Hyperplastic polyps, which arise in patients with underlying gastritis, and fundic-gland polyps, which are associated with PPI therapy, are the most common gastric polyps; however, prevalence varies widely relative to the local prevalence of Helicobacter pylori infection and use of PPI therapy. Some polyps have characteristic topography, size, and endoscopic appearance. Approximately 20% of biopsy specimens identified endoscopically as polyps have no definite pathological diagnosis. Evaluation of the phenotype of the gastric mucosa that surrounds a lesion will provide significant information crucial to the evaluation, diagnosis and management of a patient. The presence of a gastric adenoma should prompt the search for a coexistent carcinoma. The endoscopic characteristics, histopathology, pathogenesis, and management recommendations of polyps and common polypoid lesions in the stomach are discussed in this Review.

Proton pump inhibitors: actions and reactions

Proton pump inhibitors are the second most commonly prescribed drug class in the United States. The increased utilization of PPIs parallels the rising incidence of reflux disease. Owing to their clinical efficacy and relative lack of tachyphylaxis, PPIs have largely displaced H-2 receptor antagonists in the treatment of acid peptic disorders. The elevation of intragastric pH and subsequent alterations of gastric physiology induced by PPIs may yield undesired effects within the upper GI tract. The ubiquity of the various types of H(+), K(+)-ATPase could also contribute to non-gastric effects. PPIs may influence physiology in other ways, such as inducing transepithelial leak.

Importance of gastrin in the pathogenesis and treatment of gastric tumors

In addition to regulating acid secretion, the gastric antral hormone gastrin regulates several important cellular processes in the gastric epithelium including proliferation, apoptosis, migration, invasion, tissue remodelling and angiogenesis. Elevated serum concentrations of this hormone are caused by many conditions, particularly hypochlorhydria (as a result of autoimmune or Helicobacter pylori (H pylori)-induced chronic atrophic gastritis or acid suppressing drugs) and gastrin producing tumors (gastrinomas). There is now accumulating evidence that altered local and plasma concentrations of gastrin may play a role during the development of various gastric tumors. In the absence of H pylori infection, marked hypergastrinemia frequently results in the development of gastric enterochromaffin cell-like neuroendocrine tumors and surgery to remove the cause of hypergastrinemia may lead to tumor resolution in this condition. In animal models such as transgenic INS-GAS mice, hypergastrinemia has also been shown to act as a cofactor with Helicobacter infection during gastric adenocarcinoma development. However, it is currently unclear as to what extent gastrin also modulates human gastric adenocarcinoma development. Therapeutic approaches targeting hypergastrinemia, such as immunization with G17DT, have been evaluated for the treatment of gastric adenocarcinoma, with some promising results. Although the mild hypergastrinemia associated with proton pump inhibitor drug use has been shown to cause ECL-cell hyperplasia and to increase H pylori-induced gastric atrophy, there is currently no convincing evidence that this class of agents contributes towards the development of gastric neuroendocrine tumors or gastric adenocarcinomas in human subjects.

Coexpression of two distinct muscle acetylcholine receptor alpha-subunits during development

The nicotinic acetylcholine receptor is a ligand-gated channel that mediates signalling at the vertebrate neuromuscular junction. It is a pentameric complex of four different subunits, assembled with a stoichiometry of alpha 2 beta gamma delta. Muscle-like alpha-subunits have been cloned from Torpedo, mouse, calf, rat, chicken, human and Xenopus, and only a single alpha-subunit complementary DNA from each species has been detected. We report here the cloning and characterization of a second muscle alpha-subunit cDNA from Xenopus, and show that this and a previously reported Xenopus alpha-subunit cDNA are encoded by distinct genes. The novel alpha-subunit reported here is expressed uniquely in oocytes; but both types of alpha-subunit are coexpressed throughout muscle development. This latter observation indicates that the expression of these two alpha-subunits is different from a previously reported developmental 'subunit-switch' mechanism used to generate channel diversity.