Malignant potential in intestinal juvenile polyposis syndromes

Molecular Signatures for Microbe-Associated Colorectal Cancers

Background

Genetic factors and microbial imbalances play crucial roles in colorectal cancers (CRCs), yet the impact of infections on cancer initiation remains poorly understood. While bioinformatic approaches offer valuable insights, the rising incidence of CRCs creates a pressing need to precisely identify early CRC events. We constructed a network model to identify continuum states during CRC initiation spanning normal colonic tissue to pre-cancer lesions (adenomatous polyps) and examined the influence of microbes and host genetics.

Methods

A Boolean network was built using a publicly available transcriptomic dataset from healthy and adenoma affected patients to identify an invariant Microbe-Associated Colorectal Cancer Signature (MACS). We focused on Fusobacterium nucleatum ( Fn ), a CRC-associated microbe, as a model bacterium. MACS-associated genes and proteins were validated by RT-qPCR, RNA seq, ELISA, IF and IHCs in tissues and colon-derived organoids from genetically predisposed mice ( CPC-APC Min+/- ) and patients (FAP, Lynch Syndrome, PJS, and JPS).

Results

The MACS that is upregulated in adenomas consists of four core genes/proteins: CLDN2/Claudin-2 (leakiness), LGR5/leucine-rich repeat-containing receptor (stemness), CEMIP/cell migration-inducing and hyaluronan-binding protein (epithelial-mesenchymal transition) and IL8/Interleukin-8 (inflammation). MACS was induced upon Fn infection, but not in response to infection with other enteric bacteria or probiotics. MACS induction upon Fn infection was higher in CPC-APC Min+/- organoids compared to WT controls. The degree of MACS expression in the patient-derived organoids (PDOs) generally corresponded with the known lifetime risk of CRCs.

Conclusions

Computational prediction followed by validation in the organoid-based disease model identified the early events in CRC initiation. MACS reveals that the CRC-associated microbes induce a greater risk in the genetically predisposed hosts, suggesting its potential use for risk prediction and targeted cancer prevention.

Gastrointestinal Malignancy: Genetic Implications to Clinical Applications

Advances in molecular genetics have revolutionized our understanding of the pathogenesis, progression, and therapeutic options for treating gastrointestinal (GI) cancers. This chapter provides a comprehensive overview of the molecular landscape of GI cancers, focusing on key genetic alterations implicated in tumorigenesis across various anatomical sites including GIST, colon and rectum, and pancreas. Emphasis is placed on critical oncogenic pathways, such as mutations in tumor suppressor genes, oncogenes, chromosomal instability, microsatellite instability, and epigenetic modifications. The role of molecular biomarkers in predicting prognosis, guiding treatment decisions, and monitoring therapeutic response is discussed, highlighting the integration of genomic profiling into clinical practice. Finally, we address the evolving landscape of precision oncology in GI cancers, considering targeted therapies and immunotherapies.

Whole genome sequencing and disease pattern in patients with juvenile polyposis syndrome: a nationwide study

Juvenile polyposis syndrome (JPS) is a hereditary hamartomatous polyposis syndrome characterized by gastrointestinal juvenile polyps and increased risk of gastrointestinal cancer. Germline pathogenic variants are detected in SMAD4 or BMPR1A, however in a significant number of patients with JPS, the etiology is unknown. From Danish registers, and genetic department and laboratories, we identified all patients in Denmark with a clinical diagnosis of JPS and/or a pathogenic variant in BMPR1A or SMAD4. In patients where no variant had been detected, we performed genetic analysis, including whole genome sequencing. We collected clinical information on all patients to investigate the phenotypic spectrum. Sixty-six patients (mean age 40 years) were included of whom the pathogenic variant was unknown in seven patients. We detected a pathogenic variant in SMAD4 or PTEN in additional three patients and thus ≈ 95% of patients had a pathogenic germline variant. Endoscopic information was available in fifty-two patients (79%) and of these 31 (60%) fulfilled the clinical criteria of JPS. In 41 patients (79%), other types of polyps than juvenile had been removed. Our results suggest that almost all patients with a clinical diagnosis of JPS has a pathogenic variant in mainly BMPR1A, SMAD4, and more rarely PTEN. However, not all patients with a pathogenic variant fulfil the clinical criteria of JPS. We also demonstrated a wide clinical spectrum, and that the histopathology of removed polyps varied.

Occurrence of gastric cancer in patients with juvenile polyposis syndrome: a systematic review and meta-analysis

BACKGROUND AND AIMS

The true rate of gastric cancer (GC) in juvenile polyposis syndrome (JPS) is unknown because of its rarity and ascertainment bias in published literature. To better assess this, we conducted a systematic review and meta-analysis.

METHODS

MEDLINE, Embase, and Scopus databases were searched for the key words juvenile polyposis syndrome, juvenile polyps, stomach cancer, GC, SMAD4, BMPR1A, hamartomatous polyposis syndrome, hamartomas, and hereditary cancers for studies reporting upper GI manifestations in JPS. The primary outcome was the reported occurrence of GC in JPS. We then compared GC occurrence based on the presence or absence of pathogenic germline variants (PGVs) and in untested patients.

RESULTS

Eleven studies including 637 patients were included. The pooled occurrence of GC was 3.5% (95% confidence interval [CI], 1.8-5.2; I² = 12.3%) at a median age of 42.5 years (range, 15-57.6). The pooled occurrence of GC in patients with SMAD4 PGV was 10.1% (95% CI, 3.2-16.8%; I² = 54.7%). GC was reported in only 1 BMPR1A PGV carrier and was not reported in patients without an identifiable PGV. In patients with prior germline testing, the risk of GC was higher in SMAD4 PGV carriers (odds ratio, 11.6; 95% CI, 4.6-29.4; I² = 18.3%) compared with patients without SMAD4 PGV. In JPS patients with unknown status of germline testing, pooled occurrence of GC was 7.5% (95% CI, 0-15.5). There was an overall moderate risk of bias in the studies.

CONCLUSIONS

GC is highest in SMAD4-associated JPS and was not reported in patients without identifiable PGVs. The value of GC surveillance in BMPR1A PGV carriers and JPS patients without an identifiable PGV is questionable. Germline testing should be performed in all JPS patients to inform GC risk discussion and utility of surveillance.

Clinical Spectrum and Science Behind the Hamartomatous Polyposis Syndromes

The hamartomatous polyposis syndromes are a set of clinically distinct disorders characterized by the occurrence of hamartomatous polyps in the gastrointestinal tract. These syndromes include juvenile polyposis syndrome, Peutz-Jeghers syndrome, and PTEN hamartoma tumor syndrome. Although each of the syndromes has distinct phenotypes, the hamartomatous polyps can be challenging to differentiate histologically. Additionally, each of these syndromes is associated with increased lifetime risks of gene-specific and organ-specific cancers, including those outside of the gastrointestinal tract. Germline pathogenic variants can be identified in a subset of individuals with these syndromes, which facilitates molecular diagnosis and subsequent gene-enabled management in the setting of genetic counseling. Although the malignant potential of hamartomatous polyps remains elusive, timely recognition of these syndromes is important and enables presymptomatic cancer surveillance and management before symptom exacerbation. Presently, there are no standard agents to prevent the development of polyps and cancers in the hamartomatous polyposis syndromes.

Prédispositions génétiques au cancer gastrique et leur association au type histologique

About 5% of gastric cancers are associated with hereditary cancer syndromes. Histology is paramount in this context, as major susceptibility genes are associated with specific subtypes. Germline pathogenic variants in CDH1 and CTNNA1 cause Hereditary Diffuse Gastric Cancer (HDGC). Major advances have been made in the past ten years regarding HDGC. Penetrance estimates for diffuse cancer are now lower than previously thought, at 30-40%. Surveillance upper gastrointestinal endoscopy is now an acceptable alternative to prophylactic total gastrectomy. Indeed, its sensitivity in detecting advanced disease is satisfactory assuming it is performed by an expert and according to a specific protocol. The risk of intestinal-type gastric cancer is increased in patients with Lynch syndrome, although it is much lower than the risk of colorectal and endometrial cancer. Intestinal-type gastric cancers are also observed in excess in patients with hereditary polyposis, the main one being APC-associated familial adenomatous polyposis. The main and most clinically relevant manifestations in patients with polyposes remain colorectal and duodenal polyps and carcinomas, well ahead of gastric cancer. Finally, recent data point towards increased gastric cancer risk in hereditary breast and ovarian cancer.

FOCAD Indel in a Family With Juvenile Polyposis Syndrome

Juvenile polyposis syndrome (JPS) is a childhood polyposis syndrome with up to a 50% lifetime risk of gastrointestinal cancer. Germline pathogenic variants in BMPR1A and SMAD4 are responsible for around 40% of cases of JPS, but for the majority of individuals, the underlying genetic cause is unknown. We identified a family for which polyposis spanned four generations, and the proband had a clinical diagnosis of JPS. Next-generation sequencing was conducted, followed by Sanger sequencing confirmation. We identified an internal deletion of the FOCAD gene in all family members tested that altered the reading frame and is predicted to be pathogenic. We conclude that inactivation of the FOCAD gene is likely to cause JPS in this family.

Laparoscopic total gastrectomy performed for juvenile polyposis of the stomach: A case report

INTRODUCTION AND IMPORTANCE

Juvenile polyposis of the stomach (JPST) is a very rare disease and has been reported to have malignant potential. Total gastrectomy has been recommended as a standard treatment. Recently, the usefulness of laparoscopic surgery for this disease has been reported; however, in laparoscopic surgery, maintaining the surgical space is difficult because of the distended and thickened stomach wall that polyposis causes.

CASE PRESENTATION

A 64-year-old woman was admitted to our hospital because she became malnourished due to loss of appetite. She had no family history of gastrointestinal polyposis and was diagnosed with gastric polyposis and polyp-related anemia eight years previously. She received endoscopic submucosal dissection of early gastric cancer twice in another hospital. Thereafter, the patient received an annual upper gastrointestinal endoscopy and took iron supplements for anemia due to occasional bleeding from polyps. However, the number of polyps increased over time. Enhanced computed tomography showed gastric wall thickening and multiple gastric polyps. She was diagnosed as having JPST and underwent laparoscopic total gastrectomy. She was discharged on postoperative Day 10.

CLINICAL DISCUSSION

In the present case, similar to previous cases, standard laparoscopic surgery could be performed although the patient had excessive distention and congestion of the stomach. This report suggests that laparoscopic surgery is a safe and feasible option for patients with JPST and is preferable because of better cosmetic effects, especially for young female patients.

CONCLUSION

We successfully performed laparoscopic surgery to treat a rare case of JPST.

SMAD4 juvenile polyposis syndrome and hereditary haemorrhagic telangiectasia presenting in a middle-aged man as a large fungating gastric mass, polyposis in both upper and lower GI tract and iron deficiency anaemia, with no known family history

Juvenile polyposis syndrome (JPS) and hereditary haemorrhagic telangiectasia (HHT) are rare autosomal dominant diseases, where symptoms manifest at childhood. A 32-year-old man with no family history of JPS or HHT with SMAD4 gene mutation who developed signs and symptoms only at the age of 32, when he was an adult. In this article, we highlight the steps taken to diagnose this rare pathology, explain its pathophysiology and management.

Practical management of polyposis syndromes

Hereditary bowel tumours are usually part of a distinct syndrome which require management of both intestinal and extra-intestinal disease. Polyposis syndromes include: Familial adenomatous polyposis, MUTYH-associated polyposis, Serrated polyposis syndrome, Peutz-Jeghers syndrome, Juvenile polyposis syndrome and PTEN-hamartomatous syndromes. Of all colorectal cancers (CRC), 5%-10% will be due to an underlying hereditary CRC syndrome. Diagnosis and management of polyposis syndromes is constantly evolving as new scientific and technological advancements are made with respect to identifying causative genes and increased sophistication of endoscopic therapy to treat polyps. This, in addition to data yielded from meticulous record-keeping by polyposis registries has helped to guide management in what are otherwise relatively rare conditions. These data help guide clinical management of patients and their 'at-risk' relatives. Diagnosis is both genetic where possible but clinical recognition is key in the absence of an identifiable causative gene. Furthermore, some syndromes can overlap which can additionally complicate diagnosis. The principle goals of polyposis management are first to manage and treat the presenting patient and then to identify 'at-risk' patients, through screening and predictive genetic testing, endoscopic surveillance to allow therapy and guide surgical prophylaxis. Due to the complexity of diagnosis and management, patients and their families should be referred to a genetics centre or a polyposis registry where dedicated management can take place.

Non-familial juvenile polyposis of the stomach with gastric cancers: a case report

Background

Juvenile polyposis is an autosomal dominant inherited disease characterized by the development of numerous hamartomatous and nonneoplastic polyps of the gastrointestinal tract. Juvenile polyposis has also recently been reported as a predisposition for gastrointestinal cancer.

Case presentation

A 63-year-old man underwent esophagogastroduodenoscopy because of anemia and hypoalbuminemia during a follow-up for gastric polyposis, which showed multiple reddish polyps and two elevated lesions in the stomach. The elevated lesions were diagnosed as well-differentiated adenocarcinomas by biopsy. He had no specific physical findings or family history. Computed tomography showed gastric wall thickening without lymphadenopathy or distant metastasis. Colonoscopy showed an adenoma in the transverse colon. He underwent laparoscopy-assisted total gastrectomy with Roux-en-Y esophagojejunostomy. The resected specimen revealed numerous variously sized non-pedunculated polyps throughout the stomach, diagnosed histopathologically as hamartomatous polyps. The two elevated lesions were diagnosed as a well-differentiated adenocarcinoma restricted to the mucosa and a well-to-poorly differentiated adenocarcinoma invading the submucosa with prominent lymphatic permeation, respectively. Genetic analysis failed to identify any germline mutations in the genes usually associated with juvenile polyposis, including SMAD4 and BMPR1A. However, based on the few characteristic physical findings and histopathological features, the final diagnosis was juvenile polyposis restricted to the stomach.

Conclusions

This patient represented a rare case of non-familial juvenile polyposis of the stomach with gastric cancers. Juvenile polyposis has malignant potential, and patients should therefore be carefully followed up. Surgical treatment, particularly total gastrectomy, is recommended as a standard treatment in patients with juvenile polyposis of the stomach with gastric cancer.

Chromoendoscopy Plus Mucosal Resection Versus Conventional Electrocoagulation for Intestinal Polyps in Children: Two Case Series

BACKGROUND

Conventional high-frequency electrocoagulation (HFEC) of intestinal polyps may be difficult in children and endoscopic mucosal resection (EMR) could be a less invasive option. Chromoendoscopy improves tissue localization during endoscopy, but its exact influence on the outcomes of children with intestinal lesions is still unknown.

AIMS

To analyze a series of children treated with EMR or HFEC and assess the value of chromoendoscopy.

METHODS

This was a retrospective analysis of two case series of patients treated at the Gastroenterology Department of the Guiyang Children's Hospital between February 2014 and November 2016. The children underwent EMR (n = 34) or conventional HFEC (n = 120). Demographic, clinical, and perioperative data were analyzed.

RESULTS

The polyps were larger in the HFEC group [median, 3.9 (0.1-27.0) versus 1.3 (0.03-64.0) mm, P = .03]. There was a higher frequency of multiple polyps in the EMR group (50.0% versus 15.1%, P < .001). Operation time and intraoperative bleeding were similar between the two groups (both P > .05). Hospital stay was longer with EMR than with HFEC [median, 5 (3-12) versus 4 (2-14) days, P = .02]. There was no intestinal perforation in either group. Postoperative bleeding amount was similar in both groups (P = .73). In the EMR group, 19 patients were operated using chromoendoscopy, whereas only 2 patients in the HFEC group were operated.

CONCLUSION

EMR could be appropriate for the treatment of intestinal polyps in children.

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

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

Malignant tumors associated with juvenile polyposis syndrome in Japan

PURPOSE

The risk of malignant tumors developing in association with juvenile polyposis syndrome (JPS) was evaluated to explore the optimal treatment for this rare disease.

METHODS

We reviewed the data on JPS cases reported in Japan between January, 1971 and March, 2016.

RESULTS

A total of 171 cases were evaluable. Of these 171 patients, 83 (48.5%) were female and the median age at diagnosis was 28 years (range 1-80 years). The polyps were located in the stomach alone (n = 62; 36.3%), in the stomach and intestine (n = 47; 27.4%), or in the colorectum alone (n = 62; 36.3%). The sites of malignant tumors were the stomach (n = 31), colorectum (n = 29), small intestine (n = 2), breast (n = 1), and thyroid (n = 1). The lifetime risk (at 70 years) of any malignant tumor was 86.2%. The lifetime risk of gastric cancer was 73.0% and that of colorectal cancer was 51.1%. The risk of these cancers developing was dependent on the type of polyp distribution.

CONCLUSIONS

Long-term surveillance of the stomach and colorectum based on the phenotype of JPS seems a reasonable approach to monitor these patients for the development of malignant tumors.

Massive Gastric Juvenile Polyposis: A Clinicopathologic Study Using SMAD4 Immunohistochemistry

OBJECTIVES

Juvenile polyps involving the stomach are uncommon. Massive gastric juvenile polyposis is even rarer.

METHODS

We describe the clinicopathologic features of nine cases of massive gastric juvenile polyposis.

RESULTS

All patients had anemia; four had hypoalbuminemia. The polyps were composed predominantly of dilated crypts lined by columnar epithelium and abundant edematous stroma with mixed inflammatory infiltrates. One patient had a poorly differentiated adenocarcinoma, arising in juvenile polyp-associated intraepithelial neoplasia. A second patient had a well-differentiated intramucosal adenocarcinoma arising in a juvenile polyp with high-grade dysplasia. Three of our cases had polyposis restricted to the stomach. Six (66.6%) had loss of SMAD4 immunoreactivity, making them subject to severe bleeding and hypoproteinemia, as well as developing severe dysplasia or adenocarcinoma.

CONCLUSIONS

SMAD4 immunohistochemstry is a helpful ancillary diagnostic test in cases of suspected juvenile polyposis syndrome involving the stomach.

Prophylactic total gastrectomy in the management of hereditary tumor syndromes

PURPOSE

Germline mutations in several genes confer a relevant lifetime risk of gastric cancer. In this context, an increasing involvement of a surgeon can be seen, mainly with the question of performing a prophylactic operation.

METHODS

Patients with hereditary tumor syndromes predisposing for gastric cancer who received care leading to prophylactic total gastrectomy in our Center for Hereditary Tumor Syndromes were analyzed. For each patient, the multidisciplinary decision-making process, the perioperative course, and the histopathologic findings were assessed. Short-term morbidity was evaluated based on the medical reports.

RESULTS

The analysis includes nine patients (six female, three male) with a median age of 41.6 (range 23-60) years. Indication for prophylactic total gastrectomy was based on family history and genetic analysis (eight patients with a germline mutation of the CDH1 gene and one patient with a SMAD4 mutation). Removal of the entire gastric mucosa was documented intraoperatively by fresh frozen section examination. Extended (DII) lymphadenectomy was performed in four patients. Histopathologic examination of gastrectomy specimens revealed six patients (6/9, 67 %) with multifocal signet ring cell carcinomas. In our series, prophylactic total gastrectomy was a safe procedure without mortality and low morbidity.

CONCLUSIONS

Patients with hereditary syndromes predisposing for gastric cancer should be evaluated for this curative procedure in a specialized center. Further research is necessary, and the implementation of nationwide registers including patients with prophylactic gastrointestinal operations due to hereditary tumor syndrome is advisable.

Juvenile polyposis syndrome: An unusual case report of anemia and gastrointestinal bleeding in young infant

BACKGROUND

Juvenile polyposis syndrome, a rare disorder in children, is characterized with multiple hamartomatous polyps in alimentary tract. A variety of manifestations include bleeding, intussusception, or polyp prolapse. In this study, we present an 8-month-old male infant of juvenile polyposis syndrome initially presenting with chronic anemia. To the best of our knowledge, this is the youngest case reported in the literature.

METHODS

We report a rare case of an 8-month-old male infant who presented with chronic anemia and gastrointestinal bleeding initially. Panendoscopy and abdominal computed tomography showed multiple polyposis throughout the entire alimentary tract leading to intussusception. Technetium-99m-labeled red blood cell (RBC) bleeding scan revealed the possibility of gastrointestinal tract bleeding in the jejunum. Histopathological examination on biopsy samples showed Peutz-Jeghers syndrome was excluded, whereas the diagnosis of juvenile polyposis syndrome was established.

RESULTS

Enteroscopic polypectomy is the mainstay of the treatment. However, polyps recurred and occupied the majority of the gastrointestinal tract in 6 months. Supportive management was given. The patient expired for severe sepsis at the age of 18 months.

CONCLUSION

Juvenile polyposis syndrome is an inherited disease, so it is not possible to prevent it. Concerning of its poor outcome and high mortality rate, it is important that we should increase awareness and education of the parents at its earliest stages.

A case of juvenile polyposis of the stomach with multiple early gastric cancers

The present study described the case of a 24-year-old man who was diagnosed with multiple gastric hyperplastic polyps in 2004. Repeated Helicobacter pylori tests were negative, and colonoscopy revealed no specific findings. The patient started taking a proton-pump inhibitor and iron supplements as a result of anemia caused from the occasional bleeding from the polyps. The number and size of the polyps had increased over time. Endoscopic mucosal resection was occasionally performed when bleeding occurred from large polyps. Finally, histological examination revealed that the surface of the polyp had been replaced with well-differentiated adenocarcinoma in 2014. Laparoscopy-assisted total gastrectomy with Roux-en-Y esophagojejunostomy was performed in 2014. The final diagnosis was juvenile polyposis of the stomach with multiple early gastric cancers. Juvenile polyposis of the stomach is a rare disease, and its malignant potential has been reported previously. The present case highlighted the importance of not delaying surgical intervention in cases of juvenile polyposis of the stomach, since it is associated with a high occurrence of gastric cancer.

Colorectal cancer: A review of the genome-wide association studies in the kingdom of Saudi Arabia

Genome-wise association studies (GWAS) identify risk variants and modifiers that can influence the pathophysiological processes involved in colorectal cancer (CRC) and thus are important to detect associations between disease phenotypes. Our literature review, performed as per PRISMA statement indicates a significant lack of GWAS functional studies in Saudi Arabia. Therefore, studies on sequencing and mapping are needed to identify gene variants that play a role in the pathophysiology of CRC in this specific population. Because it is not apt to generalize disease associations found in other racial and/or ethnic groups to the Arabic or Middle Eastern population, it is very important to conduct GWAS taking into account multiple ethnicities in this region. In addition, linkage studies and case-control studies that include the various confounding and epigenetic factors are needed for appropriate diagnosis of CRC. We recommend that studies in this region be conducted to understand the role of gene-environment interactions across the various ethnic groups, stages of cancer, tumor type, clinical variables, and the population risk to CRC.

Upper tract juvenile polyps in juvenile polyposis patients: dysplasia and malignancy are associated with foveolar, intestinal, and pyloric differentiation

Patients with juvenile polyposis syndrome (JPS), a hereditary autosomal dominant hamartomatous polyposis syndrome, are at increased risk for colorectal adenocarcinoma. The upper gastrointestinal tract is less often involved by JPS than the colorectum, and, consequently, upper tract juvenile polyps (JPs) are not well studied. We reviewed upper endoscopies and corresponding biopsies in JPS patients documented in our Polyposis Registry. A total of 199 upper gastrointestinal biopsies from 69 endoscopies were available in 22 of 41 (54%) JPS patients. Thirteen of the 22 patients (59%) had ≥1 gastric JP; 5 also had 6 small bowel JPs. Gastric JP was identified as early as age 7 in a patient with an SMAD4 gene mutation. Two patients (9%) had high-grade dysplasia in gastric JP. Invasive adenocarcinoma was diagnosed in the gastrectomy specimen of 1 patient. Five patients had a huge gastric polyp burden; 3 underwent total gastrectomy. Three patients died of complications associated with extensive upper JP. Histologically, 8 of the 56 (14%) gastric JPs identified had dysplasia. All of the 8 polyps demonstrated intestinalized and pyloric gland differentiation intermixed with foveolar epithelium. Dysplasia was seen arising in all 3 types of epithelium. The flat gastric mucosa in 11 patients was unremarkable without inflammation or intestinal metaplasia. The 6 small bowel JPs had no dysplasia. Our findings suggest that JPS patients are at increased risk for gastric adenocarcinoma. Detection of malignancy in syndromic gastric JP indicates that the current screening procedures are insufficient in removal of precursor lesions to prevent progression to carcinoma.

Genotype-defined cancer risk in juvenile polyposis syndrome

Background

Germline mutations in SMAD4 and BMPR1A disrupt the transforming growth factor β signal transduction pathway, and are associated with juvenile polyposis syndrome. The effect of genotype on the pattern of disease in this syndrome is unknown. This study evaluated the differential impact of SMAD4 and BMPR1A gene mutations on cancer risk and oncological phenotype in patients with juvenile polyposis syndrome.

Methods

Patients with juvenile polyposis syndrome and germline SMAD4 or BMPR1A mutations were identified from a prospectively maintained institutional registry. Medical records were reviewed and the clinical patterns of disease were analysed.

Results

Thirty-five patients had germline mutations in either BMPR1A (8 patients) or SMAD4 (27). Median follow-up was 11 years. Colonic phenotype was similar between patients with SMAD4 and BMPR1A mutations, whereas SMAD4 mutations were associated with larger polyp numbers (number of patients with 50 or more gastric polyps: 14 versus 0 respectively). The numbers of patients with rectal polyps was comparable between BMPR1A and SMAD4 mutation carriers (5 versus 17). No patient was diagnosed with cancer in the BMPR1A group, whereas four men with a SMAD4 mutation developed gastrointestinal (3) or extraintestinal (1) cancer. The gastrointestinal cancer risk in patients with juvenile polyposis syndrome and a SMAD4 mutation was 11 per cent (3 of 27).

Conclusion

The SMAD4 genotype is associated with a more aggressive upper gastrointestinal malignancy risk in juvenile polyposis syndrome.

Juvenile polyposis syndrome

Juvenile polyposis syndrome (JPS) is an autosomal dominant predisposition to the occurrence of hamartomatous polyps in the gastrointestinal tract. Diagnosis of JPS is based on the occurrence of numerous colon and rectum polyps or any number of polyps with family history and, in the case of juvenile polyps, their occurrence also outside the large intestine. The JPS is caused by mutations in SMAD4 and BMPR1A. Products of the SMAD4 gene are involved in signal transduction in the transforming growth factor β pathway and BMPR1A protein is a receptor belonging to the family of transmembrane serine/threonine kinases. Both proteins are responsible for processes determining appropriate development of colonic mucosa. The JPS belongs to the group of hamartomatous polyposes. The hamartomatous polyposis syndromes constitute a group of diseases in which manifestations differ slightly and only molecular diagnostics gives the possibility of verifying the clinical diagnosis.

Appreciating the broad clinical features of SMAD4 mutation carriers: a multicenter chart review

Heterozygous loss-of-function SMAD4 mutations are associated with juvenile polyposis syndrome and hereditary hemorrhagic telangiectasia. Some carriers exhibit symptoms of both conditions, leading to juvenile polyposis-hereditary hemorrhagic telangiectasia syndrome. Three families have been reported with connective tissue abnormalities. To better understand the spectrum and extent of clinical findings in SMAD4 carriers, medical records of 34 patients (20 families) from five clinical practices were reviewed. Twenty-one percent of the patients (7/34) had features suggesting a connective tissue defect: enlarged aortic root (n = 3), aortic and mitral insufficiency (n = 2), aortic dissection (n = 1), retinal detachment (n = 1), brain aneurysms (n = 1), and lax skin and joints (n = 1). Juvenile polyposis-specific findings were almost uniformly present but variable. Ninety-seven percent of the patients had colon polyps that were generally pan-colonic and of variable histology and number. Forty-eight percent of the patients (15/31) had extensive gastric polyposis. Hereditary hemorrhagic telangiectasia features, including epistaxis (19/31, 61%), mucocutaneous telangiectases (15/31, 48%), liver arteriovenous malformation (6/16, 38%), brain arteriovenous malformation (1/26, 4%), pulmonary arteriovenous malformation (9/17, 53%), and intrapulmonary shunting (14/23, 61%), were documented in 76% of the patients. SMAD4 carriers should be managed for juvenile polyposis and hereditary hemorrhagic telangiectasia because symptoms of both conditions are likely yet unpredictable. Connective tissue abnormalities are an emerging component of juvenile polyposis-hereditary hemorrhagic telangiectasia syndrome, and larger studies are needed to understand these manifestations.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

The real face of juvenile polyposis syndrome

Colorectal cancers are mostly sporadic; some cases of familial clustering and autosomal dominant conditions are also known to occur. Juvenile polyposis syndrome (JPS) is an autosomal dominant condition caused by the mutation of the SMAD4 or the BMPR1A genes. JPS is characterized by hamartomatous polyps developing in the upper and lower intestine. Contradicting previous studies, many of these polyps can go through malignant transformation.This paper reports the case of a male patient who was continuously treated for juvenile polyposis. During the eighteen years of treatment, more than hundred polyps were endoscopically removed from his gastrointestinal tract. The patient's care was interrupted for eight years due to insufficient compliance. He was subsequently referred to our Department of Gastroenterology in severe clinical condition caused by metastatic colorectal cancer. He died after a short palliative therapy at the age of 31. His first-degree accessible relatives were further examined for juvenile polyposis syndrome. Several gastrointestinal polyps of different histological origin were observed in the deceased patient's brother, who subsequently had to undergo a left lateral hemicolectomy. Genetic analyses revealed mutations of the BMPR1A gene in the clinically affected brother, the brother's daughter, and in the deceased proband's daughter.Indebt genetic analyses helped customize and deliver care to a very specific group of individuals. We were able to identify potential family members on whom preventive care and treatment could be focused and simultaneously prevented unnecessary clinical and invasive procedures on those who were healthy. Furthermore, these analyses helped prevent future unnecessary trauma or distress on the analyzed family.

The genomics of colorectal cancer: state of the art

The concept of the adenoma-carcinoma sequence, as first espoused by Morson et al. whereby the development of colorectal cancer is dependent on a stepwise progression from adenomatous polyp to carcinoma is well documented. Initial studies of the genetics of inherited colorectal cancer susceptibility concentrated on the inherited colorectal cancer syndromes, such as Familial Adenomatous Polyposis (FAP) and Lynch Syndrome (also known as HNPCC). These syndromes, whilst easily characterisable, have a well understood sequence of genetic mutations that predispose the sufferer to developing colorectal cancer, initiated for example in FAP by the loss of the second, normal allelle of the tumour supressor APC gene. Later research has identified other inherited variants such as MUTYH (MYH) polyposis and Hyperplastic Polyposis Syndrome. Recent research has concentrated on the pathways by which colorectal adenomatous polyps not due to one of these known inherited susceptibilities undergo malignant transformation, and determination of the types of polyps most likely to do so. Also, why do individuals in certain families have a predisposition to colorectal cancer. In this article, we will discuss briefly the current state of knowledge of the genomics of the classical inherited colorectal cancer syndromes. We will also discuss in detail the genetic changes in polyps that undergo malignant transformation as well as current knowledge with regards to the epigenomic changes found in colorectal polyps.

Discovery of the BMPR1A promoter and germline mutations that cause juvenile polyposis

Juvenile polyposis (JP) is an autosomal dominant hamartomatous polyposis syndrome where affected individuals are predisposed to colorectal and upper gastrointestinal cancer. Forty-five percent of JP patients have mutations or deletions involving the coding regions of SMAD4 and BMPR1A, but the genetic basis of other cases is unknown. We set out to identify the JP gene in a large kindred having 10 affected members without SMAD4 or BMPR1A coding sequence mutations or deletions. We found a germline deletion segregating in all affected members, mapping 119 kb upstream of the coding region of BMPR1A by multiplex ligation-dependent probe amplification and comparative genomic hybridization. To further understand the genomic structure of BMPR1A, we performed 5' RACE from lymphoblastoid cell lines and normal colon tissue, which revealed four non-coding (NC) exons and two putative promoters. Further analysis of this deletion showed that it encompassed 12 433 bp, including one promoter and NC exon. The activities of each promoter and deletion constructs were evaluated by luciferase assays, and the stronger promoter sequence analyzed for changes in JP patients without SMAD4 or BMPR1A alterations. A total of 6 of 65 JP probands were found to have mutations affecting this promoter. All probands examined had diminished BMPR1A protein by ELISA, and all promoter mutations but one led to significantly reduced luciferase activity relative to the wild-type promoter reporter. We conclude that we have identified the promoter for BMPR1A, in which mutations may be responsible for as many as 10% of JP cases with unknown mutations.

Hereditary colorectal cancer: MYH-associated polyposis and other newly identified disorders

Historically, discussions of familial adenomatous polyposis and hereditary non-polyposis colon cancer have dominated lectures and writings on hereditary predisposition to colorectal cancer. In the last decade, the subject has grown well beyond the two entities. In this paper, five topics relevant to genetic risk assessment for colorectal cancer are reviewed. These include the autosomal recessive MYH-associated polyposis, hyperplastic polyposis and serrated pathway syndrome, the association of autosomal dominant juvenile polyposis with hereditary hemorrhagic telangiectasia, familial colorectal cancer type X, and the syndrome of biallelic DNA mismatch repair gene mutations. Knowledge of these entities may assist clinicians to recognize and manage cases that do not fit into the more common syndromes of colorectal cancer predisposition.

Juvenile polyposis syndrome

AIM

Report of a series of 12 cases of juvenile polyposis coli.

METHODS

The study period was from 1995 to 2005. All the patients were treated by total colectomy with rectal mucosectomy and endorectal ileoanal pullthrough with or without ileal pouch formation. Covering ileostomy was avoided in all the cases. Time taken for the surgery, postoperative complications and continence were documented.

RESULTS

The mean operating time was 4.2 h (range: 4-5 h). The mean duration of hospital stay was 16.3 days (range: 15-18 days). The most common postoperative complication was pouchitis and perianal excoriation. Initially, all the patients were passing stools at an interval of 2 h, and after 3 weeks, the frequency has reduced to 6-8 stools per day. In the follow-up after 3 months, the frequency was 3-5 per day with minimal soiling.

CONCLUSIONS

Single-stage total colectomy with rectal mucosectomy and endorectal ileoanal pull-through without covering ileostomy and pouch formation is a safe and definitive treatment for juvenile polyposis coli if the patient selection is appropriate.

The rate of germline mutations and large deletions of SMAD4 and BMPR1A in juvenile polyposis

Juvenile polyposis (JPS) is an autosomal dominant syndrome that predisposes individuals to develop gastrointestinal polyps and cancer. Germline point mutations in SMAD4 and BMPR1A have been identified as causing JPS in approximately 40-60% of patients, but few studies have looked at the rate of large deletions. In this study, we determined the overall prevalence of genetic changes of SMAD4 and BMPR1A by sequencing and by screening for larger deletions. DNA was extracted from 102 JPS probands, and each exon and intron-exon boundary of SMAD4 and BMPR1A were sequenced. Coding and non-coding exons of SMAD4 and BMPR1A were screened for deletions with multiplex ligation-dependent probe amplification (MLPA). By sequencing, 20 probands had point mutations of SMAD4 and 22 of BMPR1A. By MLPA, one proband had deletion of most of SMAD4, one of both BMPR1A and PTEN, one of the 5' end of BMPR1A, and another of the 5' end of SMAD4. The overall prevalence of SMAD4 and BMPR1A point mutations and deletions in JPS was 45% in the largest series of patients to date. Large deletions are less frequent in JPS patients, but represent other heritable causes of JPS, which should be screened for in pre-symptomatic genetic testing.

Epidemiology and management options for colorectal cancer in children

Colorectal carcinoma (CRC), although primarily a disease of adulthood, accounts for 2% of malignancies in adolescents and has been reported in children as young as 9 months of age. Our knowledge of CRC in pediatrics is based on a handful of case series and case reports. Apart from one small clinical trial, there has been a lack of prospective clinical studies in this age group. Based on these published reports, most CRC in children is sporadic, but it can also arise in the setting of predisposing conditions, such as gastrointestinal polyposis syndromes, nonpolyposis familial cancer syndromes, and inflammatory bowel disease. Despite some similarities to adult disease, CRC in childhood may be intrinsically different biologically, because it differs from adult-onset CRC in several respects. Childhood CRC tends to be diagnosed at an advanced stage, is largely of mucinous histology, and (probably because of these features) tends to have a poorer outcome. As a result of its rarity in children and the lack of prospective pediatric studies, recommendations for therapy are primarily extrapolated from adult clinical trials. A review of pediatric case series in the English literature emphasizes the prognostic significance of stage of disease, as well as extent of surgical resection. As in adults, early detection is critical in an effort to capture the disease at less advanced stages. Complete surgical resection with aggressive lymph node dissection is essential for cure, and neoadjuvant chemotherapy may be used in an effort to render unresectable lesions resectable. Active agents in adults with CRC include fluorouracil, folinic acid (leucovorin), oxaliplatin, and irinotecan. Furthermore, newer targeted therapeutic agents, such as bevacizumab and cetuximab, have added additional efficacy to the standard chemotherapy backbone. Collaborative multi-institutional pediatric clinical trials are needed to evaluate the prognosis, optimal treatment response, and the basic biology of childhood onset CRC.

First report of ovarian dysgerminoma in Cowden syndrome with germline PTEN mutation and PTEN-related 10q loss of tumor heterozygosity

We present the first report of ovarian dysgerminoma in Cowden syndrome, presenting in a 7-year-old girl. In her second decade, a hamartomatous soft tissue extremity mass and diffuse gastrointestinal hamartomatous polyposis with pathologic features suggestive of either juvenile, Peutz-Jeghers, or Cowden polyps were identified, along with diffuse esophageal glycogenic acanthosis and skin manifestations. During regular thyroid cancer surveillance under the provisional diagnosis of Cowden syndrome, papillary thyroid carcinoma and benign follicular nodules were diagnosed at age 23. PTEN mutational analysis revealed a novel germline nonsense point mutation of Q219X. Loss of PTEN heterozygosity was also present in the ovarian dysgerminoma. Parental mutation testing and phenotype screening were negative. The correct classification of Cowden syndrome is difficult because of its protean manifestations and overlapping phenotypes with other genetic and noninherited pathologies, particularly regarding various gastrointestinal polyposis syndromes. Despite the challenges, correct classification is critical to patient care because of the associated cancer predispositions and necessary surveillance programs. This is the first report of Cowden syndrome presenting with ovarian dysgerminoma, which implicates PTEN in the molecular pathogenesis of dysgerminoma and adds it to the phenotypic manifestations of Cowden syndrome.

Hamartomatous polyposis syndromes

Since the histologic description of the hamartomatous polyp in 1957 by Horrilleno and colleagues, descriptions have appeared of several different syndromes with the propensity to develop these polyps in the upper and lower gastrointestinal tracts. These syndromes include juvenile polyposis, Peutz-Jeghers syndrome, hereditary mixed polyposis syndrome, and the phosphatase and tensin homolog gene (PTEN) hamartoma tumor syndromes (Cowden and Bannayan-Riley-Ruvalcaba syndromes), which are autosomal-dominantly inherited, and Cronkhite-Canada syndrome, which is acquired. This article reviews the clinical aspects, the molecular pathogenesis, the affected organ systems, the risks of cancer, and the management of these hamartomatous polyposis syndromes. Although the incidence of these syndromes is low, it is important for clinicians to recognize these disorders to prevent morbidity and mortality in these patients, and to perform presymptomatic testing in patients at risk.

Hamartomatous polyposis syndromes

The hamartomatous polyposis syndromes are a heterogeneous group of disorders that share an autosomal-dominant pattern of inheritance and are characterized by hamartomatous polyps of the gastrointestinal tract. These syndromes include juvenile polyposis syndrome, Peutz-Jeghers syndrome and the PTEN hamartoma tumor syndrome. The frequency and location of the polyps vary considerably among syndromes, as does the affected patient's predisposition to the development of gastrointestinal and other malignancies. Although the syndromes are uncommon, it is important for the clinician to recognize these disorders because they are associated with considerable morbidity and mortality, not only from malignancy but also from nonmalignant manifestations such as bleeding, intussusception, and bowel obstruction. Each hamartomatous polyposis syndrome has its own distinctive organ-specific manifestations and each requires a different surveillance strategy, which makes accurate diagnosis crucial for appropriate patient management. The availability of clinical genetic testing for these disorders means that appropriate recognition allows for timely referral for cancer genetic counseling, and often allows for predicative testing in at-risk family members. Promisingly, an understanding of the molecular pathogenesis of these disorders offers insights into the mechanisms underlying the development of sporadic malignancy, and enables rational selection of targeted therapies that warrant further investigation.

Pathology of the hereditary colorectal carcinoma

Positive familial history (first or second degree relative) for colorectal carcinoma (CRC) can be found in approximately 30% of all newly diagnosed cases, but less than 5% will be due to a defined genetic category of hereditary CRC. Pathologic examination of the biopsy or resection specimen can help in identification of unsuspected cases of certain forms of hereditary CRC due to the characteristic morphologic findings. Additional immunohistochemical and molecular studies can then provide a definitive diagnosis. The most common form of hereditary CRC is Lynch syndrome (hereditary non-polyposis colorectal cancer, HNPCC) which is characterized by proximally located tumors frequently showing mucinous and medullary type histologic features. The syndrome results from a germline mutation in genes for mismatch repair (MMR) proteins leading to insufficient DNA repair and development of tumors characterized by high levels of instability in short tandem repeat DNA sequences (microsatellites) or "microsatellite instability-high" (MSI-H). The presence of intra-epithelial lymphocytes is single most helpful morphologic feature in identification of CRC caused by deficiency in MMR proteins, for which MSI-H status is a good marker but morphologic features and MSI-H do not differentiate tumors caused by germline mutations in one of the MMR genes (Lynch syndrome) from sporadic CRC due to inactivation of MLH-1 through promoter methylation. Hereditary CRC may also arise in various familial polyposis syndromes which include familial adenomatous polyposis (FAP), attenuated FAP and other multiple adenomas syndromes as well as various hamartomatous polyposis syndromes. All of these rare conditions have characteristic clinical presentation and histopathologic features of polyps and most of them have defined genetic abnormality. Furthermore, due to the germline nature of mutations in these syndromes, various extracolonic manifestations may be the first sign of the disease and knowledge of such associations can greatly improve the quality of care for these patients. The role of pathologist is to recognize these characteristics and initiate appropriate follow up with clinicians and genetic counselors.

The patient with multiple intestinal polyps

The management of patients with multiple intestinal polyps may be difficult and greatly depends on the correct classification. Polyposis syndromes account for less than 1% of newly diagnosed colorectal cancers. In addition the risk for extracolonic cancer is increased in most syndromes. Here we report the case of a difficult patient with severe gastric polyposis and we present a review of polyposis syndromes such as classical and attenuated familial adenomatous polyposis (FAP), MYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis as well as rare polyposis syndromes. The most practical approach for the diagnostic workup in patients with newly diagnosed gastrointestinal polyposis is based on the histological typing of polyps. In addition, a detailed family history regarding cancer, polyps and congenital abnormalities should be obtained from every polyposis patient. Patients with multiple adenomas are most likely to suffer from FAP, AFAP or MAP. Of these, younger age and higher polyp count are most likely a diagnosis of typical FAP. Older age and fewer polyps favour a diagnosis of AFAP or MAP. Germline testing of the APC gene is suggested, and if negative, MYH gene testing should be done. In patients with hamartomas, extraintestinal features should be evaluated and reference histology should be initiated. In addition panintestinal imaging should be performed with EGD, colonoscopy and small bowel imaging (PE, CE, and MR) enteroclysis. For diagnostic and therapeutic problems a familial colorectal cancer center should be consulted. Using this algorithm, correct classification and adequate treatment should be possible for every polyposis patient.

Nonfamilial juvenile polyposis coli manifesting as massive lower gastrointestinal hemorrhage: report of two cases

Juvenile polyposis syndrome is an uncommon hamartomatous disorder with gastrointestinal (GI) manifestations of varying degree and malignant potential. We report the cases of an 8-year-old girl and a 5-year-old girl who suffered massive lower GI hemorrhage. Neither patient had a family history of polyposis. After the patients were stabilized, radiological evaluation, laparotomy, and intraoperative colonoscopy revealed multiple polyps in the colon. Both patients underwent total colectomy, mucosal proctectomy, and ileoanal anastomosis. The diagnosis of nonfamilial juvenile polyposis was based on the histological findings and the absence of a family history. To our knowledge, this presentation of juvenile polyposis has been reported only twice before. We discuss the clinical features and diagnosis of juvenile polyposis and the treatment options. Although juvenile polyposis is a rare condition in children, it should be considered in the differential diagnosis of life-threatening GI hemorrhage.

Contiguous gene deletion within chromosome arm 10q is associated with juvenile polyposis of infancy, reflecting cooperation between the BMPR1A and PTEN tumor-suppressor genes

We describe four unrelated children who were referred to two tertiary referral medical genetics units between 1991 and 2005 and who are affected with juvenile polyposis of infancy. We show that these children are heterozygous for a germline deletion encompassing two contiguous genes, PTEN and BMPR1A. We hypothesize that juvenile polyposis of infancy is caused by the deletion of these two genes and that the severity of the disease reflects cooperation between these two tumor-suppressor genes.

Gastrointestinal tumors in children and adolescents

Tumors of the pediatric gastrointestinal tract are extremely rare. Their infrequent presentation at treatment centers has not allowed for the development of standardized treatment protocols and prospective review. The most prevalent gastrointestinal neoplasms and malignancies are described, including gastrointestinal lymphoma, colorectal carcinoma, carcinoid tumors, gastrointestinal stromal tumors, leiomyomas, juvenile polyps, inflammatory pseudotumors, gastric tumors, and Peutz-Jeghers polyposis syndrome. Current recommendations for the medical and surgical management of these tumors are reviewed and summarized for this vast group of gastrointestinal neoplasms in children.

Surgical Implications of Colorectal Cancer Genetics

The applications of genetics in colorectal cancer are not limited to identifying germ-line mutations in genetically predisposed individuals. Reports on the use of molecular genetic markers as prognostic factors and for assessing the response to therapy are common in the literature. As the primary caregiver in the majority of these cases, the surgeon needs a basic knowledge of colorectal genetics and their implications to the patient and the patient's family. This article discusses a practical approach for some of the issues likely to be encountered by the surgeon.

A review of juvenile polyposis syndrome

Juvenile Polyposis Syndrome is an uncommon hamartomatous disorder with significant gastrointestinal malignant potential. Mutations in SMAD4 and BMPR1A, implicated in the Transforming Growth Factor beta pathway, have recently been characterized, and hold significance in the management of patients and at risk family members. This article reviews our knowledge to date of the genetics and clinicopathological features of the Juvenile Polyposis Syndrome, and discusses the current expert recommendations for genetic testing, disease screening and management.

Vessels' morphology in SMAD4 and BMPR1A-related juvenile polyposis

Juvenile polyposis syndrome is a hamartomatous intestinal polyposis associated with malignant changes in 20% of patients at an early age. Germline mutations mostly involve two genes, SMAD4 and BMPR1, with no strong evidence of phenotype-genotype correlation, which could be predictive of the specific long-term evolution. In contrast, PTEN mutations are more commonly associated with Cowden and related diseases. Forty-two unrelated patients affected by juvenile polyposis syndrome were analyzed for germline alterations in the BMPR1A and SMAD4 genes, and for clinical and histological features. Deleterious mutations were found in 14/42 (33%) patients: 5 in BMPR1A and 9 in SMAD4. Low-grade adenomas were present in both SMAD4 and BMPR1A mutation carriers; only patients with SMAD4 mutations harbored carcinoma lesions (5/9). Malformative vessels were present in all SMAD4 related polyps when the mutation involved codons prior to position 423. No gastric polyps were observed in BMPR1A mutation carriers. SMAD4 germline mutations are responsible for a more aggressive digestive phenotype in patients with juvenile polyposis. The presence of malformative vessels within the stromal component might be a useful tool to drive the subsequent genetic and clinical management.

Inherited polyposis syndromes: molecular mechanisms, clinicopathology, and genetic testing

The inherited polyposis syndromes are a group of conditions in which multiple gastrointestinal polyps occur in the lumen of the gastrointestinal tract, most exhibit an increased risk of colon cancer. Benign and malignant extraintestinal tumors might also be observed. Recent elucidation of the underlying gene mutations has contributed to our understanding of the cell biology and molecular mechanisms associated with gastrointestinal tumorigenesis. Developments have also allowed genetic testing to become an integral component in accurate diagnosis, categorization, and management of inherited polyposis syndromes. In this review, we will focus on familial adenomatous polyposis, mutY human homologue-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis, and Cowden syndrome. It is essential that both physician and patient understand the benefits and limitations of genetic testing before submission of samples to the laboratory. There are many issues accompanying molecular diagnosis of cancer syndromes, and genetic counseling is an essential prelude to genetic testing.