Juvenile polyposis, hereditary hemorrhagic telangiectasia, and early onset colorectal cancer in patients with SMAD4 mutation

Phenotypic characterisation of SMAD4 variant carriers

BACKGROUND

Both hereditary haemorrhagic telangiectasia (HHT) and juvenile polyposis syndrome (JPS) are known to be caused by SMAD4 pathogenic variants, with overlapping symptoms for both disorders in some patients. Additional connective tissue disorders have also been reported. Here, we describe carriers of SMAD4 variants followed in an HHT reference centre to further delineate the phenotype.

METHODS

Observational study based on data collected from the Clinical Investigation for the Rendu-Osler Cohort database.

RESULTS

Thirty-three participants from 15 families, out of 1114 patients with HHT, had an SMAD4 variant (3%).Regarding HHT, 26 out of 33 participants (88%) had a definite clinical diagnosis based on Curaçao criteria. Complication frequencies were as follows: epistaxis (n=27/33, 82%), cutaneous telangiectases (n=19/33, 58%), pulmonary arteriovenous malformations (n=17/32, 53%), hepatic arteriovenous malformations (AVMs) (n=7/18, 39%), digestive angiodysplasia (n=13/22, 59%). No cerebral AVMs were diagnosed.Regarding juvenile polyposis, 25 out of 31 participants (81%) met the criteria defined by Jass et al for juvenile polyposis syndrome. Seven patients (21%) had a prophylactic gastrectomy due to an extensive gastric polyposis incompatible with endoscopic follow-up, and four patients (13%) developed a digestive cancer.Regarding connective tissue disorders, 20 (61%) had at least one symptom, and 4 (15%) participants who underwent echocardiography had an aortic dilation.

CONCLUSION

We describe a large cohort of SMAD4 variant carriers in the context of HHT. Digestive complications are frequent, early and diffuse, justifying endoscopy every 2 years. The HHT phenotype, associating pulmonary and hepatic AVMs, warrants systematic screening. Connective tissue disorders broaden the phenotype associated with SMAD4 gene variants and justify systematic cardiac ultrasound and skeletal complications screening.

Hamartomatous polyps: Diagnosis, surveillance, and management

Hereditary polyposis syndrome can be divided into three categories: Ade-nomatous, serrated, and hamartomatous polyps. Hamartomatous polyps, malformations of normal tissue presenting in a disorganized manner, are characterized by an autosomal dominant inheritance pattern. These syndromes exhibit hamartomatous gastrointestinal polyps in conjunction to extra-intestinal manifestations, which require conscientious and diligent monitoring. Peutz-Jeghers syndrome, Cowden syndrome, and juvenile polyposis syndrome are the most common displays of hamartomatous polyposis syndrome (HPS). Diagnosis can be pursued with molecular testing and endoscopic sampling. Early identification of these autosomal dominant pathologies allows to optimize malignancy sur-veillance, which helps reduce morbidity and mortality in both the affected patient population as well as at-risk family members. Endoscopic surveillance is an important pillar of prognosis and monitoring, with many patients eventually requiring surgical intervention. In this review, we discuss the diagnosis, surveillance, and management of HPS.

Hereditary haemorrhagic telangiectasia in Danish patients with pathogenic variants in SMAD4: a nationwide study

BACKGROUND AND AIMS

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant condition characterised by recurrent epistaxis, telangiectatic lesions in the skin and mucosal membranes, and arteriovenous malformations (AVMs) in various organs. In 3%-5% of patients, HHT is caused by pathogenic germline variants (PVs) in SMAD4, and these patients often have additional symptoms of juvenile polyposis syndrome and thoracic aneurysms. The phenotypic spectrum of SMAD4-associated HHT is less known, including the penetrance and severity of HHT. We aimed to investigate the phenotypic spectrum of HHT manifestations in Danish patients with PVs in SMAD4 and compare the findings with current literature.

METHODS

The study is a retrospective nationwide study with all known Danish patients with PVs in SMAD4. In total, 35 patients were included. The patients were identified by collecting data from genetic laboratories, various databases and clinical genetic departments across the country. Clinical information was mainly collected from the Danish HHT-Centre at Odense University Hospital.

RESULTS

Twenty-nine patients with PVs in SMAD4 (83%) were seen at the HHT-Centre. Seventy-six per cent of these fulfilled the Curaçao criteria, 86% experienced recurrent epistaxis and 83% presented with telangiectatic lesions at different anatomical localisations. Almost 60% had AVMs, mainly pulmonary and hepatic, while none was found to have cerebral AVMs. Fifteen per cent had thoracic aortic abnormalities.

CONCLUSION

We present a nationwide study of one of the largest populations of patients with PVs in SMAD4 that has systematically been examined for HHT manifestations. The patients presented the full spectrum of HHT-related manifestations and the majority fulfilled the Curaçao criteria.

Phenotypic diversity among juvenile polyposis syndrome patients from different ethnic background

Abstract

Juvenile polyposis syndrome (JPS), has diverse phenotypes. Aim: To assess mutation rate, clinical features and genotype-phenotype correlation among Israeli JPS kindreds from different ethnicities.

Methods

Patients’ data were extracted retrospectively from 5 centers.

Results

Thirty five kindreds (49 patients) were included. Thirty one (89%) Jewish [10 (32%) Ashkenazi; 9 (29%) Sephardi; 11 (35%) non-Russia former Soviet-Union countries (NRFSU), one (3%) unknown]. 40/49 individuals from 27 families underwent genetic testing. Among them 34, from 21 families (85, 78%, respectively) had a pathogenic mutation: BMPR1A n = 15 (71%), SMAD4 n = 6 families (29%). While no SMAD4 mutation was described among Jewish families from NRFSU, 7 NRFSU families carried a founder mutation comprising a large genomic deletion of BMPR1A. GI involvement was reported in 42 patients (86%): colonic polyps (n = 40, 95%, > 50 polyps n = 14, 35%) and 12 underwent colonic resection. Fourteen patients (34%) had gastric or small bowel involvement (n = 5) and 4\14 underwent gastrectomy due to polyp burden. Families from NRFSU had more gastric involvement (66.7% vs. 22.2%- Sephardic and 20%- Ashkenazi Jews; p = 0.038), with more gastric polyps (p = 0.017).

Conclusions

We demonstrated a high rate of mutation detection in the heterogeneous population of Israel. Patients from NRFSU with BMPR1A mutation had high rate of gastric involvement.

Hereditary haemorrhagic telangiectasia: an overview from an ear, nose and throat perspective

Patients with hereditary haemorrhagic telangiectasia can present with a multitude of symptoms caused by telangiectasia and arteriovenous malformations in the nose, brain, gastrointestinal tract, liver and spinal cord. Clinicians should be aware of the potential diagnosis of hereditary haemorrhagic telangiectasia and how to manage these patients both in the acute and chronic setting. Identifying these patients and optimising their management can help reverse the reduced life expectancy back to that of the normal population. The management of these patients is complex and often requires a multidisciplinary approach, with difficult discussions to be had around screening for arteriovenous malformations and genetic testing. The stepwise management ladder can be used in both the medical and surgical strategies; there are multiple pharmacological and surgical options available, all with their own side effects and risks. Patient education is key to help informed decision making. This article outlines the clinical characteristics of the disease and management options available.

Genetic counseling and testing for hereditary hemorrhagic telangiectasia

Genetic counseling is an important means of identifying a patient's genetic risk of hereditary hemorrhagic telangiectasia (HHT) and assisting patients in making informed decisions about their health. With an increase in understanding of the genetic mechanisms underlying HHT over the last decade, genetic counseling is increasingly being incorporated into the care of patients affected by HHT. In addition to refining the diagnosis of symptomatic patients, genetic testing can help to distinguish asymptomatic, at-risk patients from those who are unaffected by HHT. The purpose of this review article is to summarize the current knowledge regarding the role of genetic counseling and genetic testing in identifying and managing HHT in at-risk populations. This article also reviews the guidelines, outcomes, risks, and challenges of genetic counseling and testing for HHT in various patient populations, and provides an algorithm for the use of genetic counseling in symptomatic and asymptomatic patients.

Predictors of mortality in patients with hereditary hemorrhagic telangiectasia

Background

Retrospective questionnaire and healthcare administrative data suggest reduced life expectancy in untreated hereditary hemorrhagic telangiectasia (HHT). Prospective data suggests similar mortality, to the general population, in Denmark’s centre-treated HHT patients. However, clinical phenotypes vary widely in HHT, likely affecting mortality. We aimed to measure predictors of mortality among centre-treated HHT patients. HHT patients were recruited at 14 HHT centres of the Brain Vascular Malformation Consortium (BVMC) since 2010 and followed annually. Vital status, organ vascular malformations (VMs) and clinical symptoms data were collected at baseline and during follow-up (N = 1286). We tested whether organ VMs, HHT symptoms and HHT genes were associated with increased mortality using Cox regression analysis, adjusting for patient age, sex, and smoking status.

Results

59 deaths occurred over average follow-up time of 3.4 years (max 8.6 years). A history of anemia was associated with increased mortality (HR = 2.93, 95% CI 1.37–6.26, p = 0.006), as were gastro-intestinal (GI) bleeding (HR = 2.63, 95% CI 1.46–4.74, p = 0.001), and symptomatic liver VMs (HR = 2.10, 95% CI 1.15–3.84, p = 0.015). Brain VMs and pulmonary arteriovenous malformations (AVMs) were not associated with mortality (p > 0.05). Patients with SMAD4 mutation had significantly higher mortality (HR = 18.36, 95% CI 5.60–60.20, p < 0.001) compared to patients with ACVRL1 or ENG mutation, but this estimate is imprecise given the rarity of SMAD4 patients (n = 33, 4 deaths).

Conclusions

Chronic GI bleeding, anemia and symptomatic liver VMs are associated with increased mortality in HHT patients, independent of age, and in keeping with the limited treatment options for these aspects of HHT. Conversely, mortality does not appear to be associated with pulmonary AVMs or brain VMs, for which patients are routinely screened and treated preventatively at HHT Centres. This demonstrates the need for development of new therapies to treat chronic anemia, GI bleeding, and symptomatic liver VMs in order to reduce mortality among HHT patients.

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.

Juvenile polyposis syndrome-hereditary hemorrhagic telangiectasia associated with a SMAD4 mutation in a girl

Juvenile polyposis syndrome (JPS) and hereditary hemorrhagic telangiectasia (HHT) are both relatively rare hereditary disorders. Some patients with the SMAD4 gene mutation develop both JPS and HHT, a condition termed JPS-HHT. We herein report a case of childhood-onset JPS-HHT. At nine years old, the patient underwent colonoscopy under suspicion of Crohn's disease, which revealed multiple polyps. A genetic analysis for familial adenomatous polyposis and Peutz-Jeghers syndrome found no mutations. After several years, extraintestinal manifestations, such as repeated epistaxis and several telangiectasias in the upper palate and stomach, were identified, which led to the performance of gene mutation analysis for SMAD4. As a result, a missense mutation in exon 8, codon 361 from arginine to cysteine (c.1081 C>T) was found. Based on this finding, the patient underwent cerebral magnetic resonance angiography, pulmonary perfusion scintigraphy and thoracoabdominal contrast computed tomography. The examination revealed that she had pulmonary arteriovenous fistulas and arteriovenous malformations in both the liver and right mammary gland. Thus, continuous surveillance for vascular lesions and gastrointestinal cancer is scheduled. Making a precise diagnosis of JPS-HHT can lead to the detection of asymptomatic complications and enable appropriate future disease management.

Juvenile polyposis syndrome might be misdiagnosed as familial adenomatous polyposis: a case report and literature review

BACKGROUND

Juvenile polyposis syndrome (JPS) is a rare disorder characterized by the presence of multiple juvenile polyps in the gastrointestinal tract, and germline mutations in SMAD4 or BMPR1A. Due to its rarity and complex clinical manifestation, misdiagnosis often occurs in clinical practice.

CASE PRESENTATION

A 42-year-old man with multiple pedunculated colorectal polyps and concomitant rectal adenocarcinoma was admitted to our hospital. His mother had died of colon cancer. He was diagnosed with familial adenomatous polyposis (FAP) and underwent total proctocolectomy and ileal pouch anal anastomosis. Two polyps were selected for pathological examination. One polyp had cystically dilated glands with slight dysplasia. The other polyp displayed severe dysplasia and was diagnosed as adenoma. Three years later, his 21-year-old son underwent a colonoscopy that revealed more than 50 pedunculated colorectal juvenile polyps. Both patients harbored a germline pathogenic mutation in BMPR1A. Endoscopic resection of all polyps was attempted but failed. Finally, the son received endoscopic resection of polyps in the rectum and sigmoid colon, and laparoscopic subtotal colectomy. Ten polyps were selected for pathological examination. All were revealed to be typical juvenile polyps, with cystically dilated glands filled with mucus. Thus, the diagnosis of JPS was confirmed in the son. A review of the literatures revealed that patients with JPS can sometimes have adenomatous change. Most polyps in patients with JPS are benign hamartomatous polyps with no dysplasia. A review of 767 colorectal JPS polyps demonstrated that 8.5% of the polyps contained mild to moderate dysplasia, and only 0.3% had severe dysplasia or cancer. It is difficult to differentiate juvenile polyps with dysplasia from adenoma, which could explain why juvenile polyps have been reported to have adenomatous changes in patients with JPS. Therefore, patients with JPS, especially those with concomitant dysplasia and adenocarcinoma, might be easily diagnosed as FAP in clinical practice.

CONCLUSIONS

Juvenile polyp with dysplasia is often diagnosed as adenoma, which might lead to the misdiagnosis of JPS as FAP. The differential diagnosis of JPS versus FAP, should be based on comprehensive evaluation of clinical presentation, endoscopic appearance and genetic investigations; not on the presence or absence of adenoma.

SMAD4 Deficiency Leads to Development of Arteriovenous Malformations in Neonatal and Adult Mice

Background

Hereditary hemorrhagic telangiectasia (HHT) is a rare genetic vascular disorder caused by mutations in endoglin (ENG), activin receptor‐like kinase 1 (ACVRL1;ALK1), or SMAD4. Major clinical symptoms of HHT are arteriovenous malformations (AVMs) found in the brain, lungs, visceral organs, and mucosal surface. Animal models harboring mutations in Eng or Alk1 recapitulate all of these HHT clinical symptoms and have been useful resources for studying mechanisms and testing potential drugs. However, animal models representing SMAD4 mutations have been lacking. The goal of this study is to evaluate Smad4‐inducible knockout (iKO) mice as an animal model of HHT and compare the phenotypes with other established HHT animal models.

Methods and Results

Global Smad4 deletion was induced at neonatal and adult stages, and hemoglobin levels, gastrointestinal hemorrhage, and presence of aberrant arteriovenous connections were examined. Neonatal Smad4‐iKO mice exhibited signs of gastrointestinal bleeding and AVMs in the brain, intestine, nose, and retina. The radial expansion was decreased, and AVMs were detected on both distal and proximal retinal vasculature of Smad4‐iKOs. Aberrant smooth muscle actin staining was observed in the initial stage AVMs and their connecting veins, indicating abnormal arterial flow to veins. In adult mice, Smad4 deficiency caused gastrointestinal bleeding and AVMs along the gastrointestinal tract and wounded skin. HHT‐related phenotypes of Smad4‐iKOs appeared to be comparable with those found in Alk1‐iKO and Eng‐iKO mice.

Conclusions

These data further confirm that SMAD signaling is crucial for normal arteriovenous network formation, and Smad4‐iKO will be an alternative animal model of AVM research associated with HHT.

Management of Juvenile Polyposis Syndrome in Children and Adolescents: A Position Paper From the ESPGHAN Polyposis Working Group

The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Polyposis Working Group developed recommendations to assist clinicians and health care providers with appropriate management of patients with juvenile polyposis. This is the first juvenile polyposis Position Paper published by ESPGHAN with invited experts. Many of the published studies were descriptive and/or retrospective in nature, consequently after incorporating a modified version of the GRADE system many of the recommendations are based on expert opinion. This ESPGHAN Position Paper provides a guide for diagnosis, assessment, and management of juvenile polyposis syndrome in children and adolescents, and will be helpful in the appropriate management and timing of procedures in children and adolescents. The formation of international collaboration and consortia is proposed to monitor patients prospectively to advance our understanding of juvenile polyposis conditions.

Hereditary Colorectal Cancer Syndromes

OBJECTIVES

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

DATA SOURCES

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

CONCLUSION

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

IMPLICATIONS FOR NURSING PRACTICE

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

Massive juvenile polyposis of the stomach in a family with SMAD4 gene mutation

Relatively little is known on the genotype-phenotype correlations between SMAD4 gene mutations, juvenile polyposis of the intestine and Hereditary Hemorrhagic Teleangectasia. We describe a family in which the proband (a 46-year old woman) had massive polyposis of the stomach-leading to surgery-with high-grade dysplasia at histology. Molecular analysis was carried out using Next Generation sequencing techniques with Miseq Illumina Platforms and a minimal coverage of 40 reads. In the proband, the analysis showed the presence of a truncating mutation in the SMAD4 gene (c.1213dupC, a variant previously associated with juvenile polyposis and Hereditary Hemorrhagic Teleangectasia). The same mutation was detected in two other members of the family (father and brother of the proband), who showed massive polypoid involvement of the stomach at gastroscopy. By taking the family history, subtle evidence of Hereditary Teleangectasia was found (nasal bleeding and arterovenous malformations) in the three gene carriers. Colonoscopy showed polyp occurrence in all three affected members with SMAD4 mutation, with prevalence of adenomatous lesions in one (father), of hamartomas in the brother, and of a mix of histological types in the proband. The main features of the family can be summarized as follows: (A) In hereditary juvenile polyposis, lesions of different histology can be detected at colonoscopy; (B) In the gene carriers of SMAD4 mutations, lesions of the stomach require careful surveillance and, when necessary, surgical interventions; (C) Signs and symptoms of Hereditary Hemorrhagic Teleangectasia should be suspected (and searched) in individuals with SMAD4 constitutional mutations.

Juvenile Idiopathic Arthritis Associated with Combined JP-HHT Syndrome: A Novel Phenotype Associated with a Novel Variant in SMAD4

Juvenile polyposis (JP) syndrome is characterized by multiple hamartomatous polyps of the gastrointestinal tract. Hereditary hemorrhagic telangiectasia (HHT) is a vascular dysplasia characterized by telangiectasia in the skin, mucous membranes, and arteriovenous malformations in other organs. Individuals with JP-HHT syndrome have variable features of both rare disorders, attributed to heterozygous mutations in the SMAD4 gene. Systemic juvenile idiopathic arthritis (JIA) is a severe, chronic disease marked by arthritis and systemic inflammation for which the cause remains unknown. JIA has never been described in association with SMAD4 -related disease. We describe a case of JP-HHT syndrome with a novel SMAD4 variant, c.1052A > T (p.D351V), in which the child also had JIA manifestation.

Influential Mutations in the SMAD4 Trimer Complex Can Be Detected from Disruptions of Electrostatic Complementarity

This article examines three techniques for rapidly assessing the electrostatic contribution of individual amino acids to the stability of protein-protein complexes. Whereas the energetic minimization of modeled oligomers may yield more accurate complexes, we examined the possibility that simple modeling may be sufficient to identify amino acids that add to or detract from electrostatic complementarity. The three methods evaluated were (a) the elimination of entire side chains (e.g., glycine scanning), (b) the elimination of the electrostatic contribution from the atoms of a side chain, called nullification, and (c) side chain structure prediction using SCWRL4. These techniques generate models in seconds, enabling large-scale mutational scanning. We evaluated these techniques on the SMAD2/SMAD4 heterotrimer, whose formation plays a crucial role in antitumor pathways. Many studies have documented the clinical and structural effect of specific mutations on trimer formation. Our results describe how glycine scanning yields more specific predictions, although nullification may be more sensitive, and how side chain structure prediction enables the identification of uncharged-to-charge mutations.

TGF-β Family Signaling in Tumor Suppression and Cancer Progression

Transforming growth factor-β (TGF-β) induces a pleiotropic pathway that is modulated by the cellular context and its integration with other signaling pathways. In cancer, the pleiotropic reaction to TGF-β leads to a diverse and varied set of gene responses that range from cytostatic and apoptotic tumor-suppressive ones in early stage tumors, to proliferative, invasive, angiogenic, and oncogenic ones in advanced cancer. Here, we review the knowledge accumulated about the molecular mechanisms involved in the dual response to TGF-β in cancer, and how tumor cells evolve to evade the tumor-suppressive responses of this signaling pathway and then hijack the signal, converting it into an oncogenic factor. Only through the detailed study of this complexity can the suitability of the TGF-β pathway as a therapeutic target against cancer be evaluated.

Gastrointestinal Manifestations of Hereditary Hemorrhagic Telangiectasia (HHT): A Systematic Review of the Literature

Hereditary hemorrhagic telangiectasia (HHT), also called Osler-Weber-Rendu syndrome, is an autosomal dominant genetic disease that affects the vasculature of numerous organs. The prevalence of HHT is estimated to be between 1.5 and 2 persons per 10,000. While there is still much to learn about this condition, there is an increasing understanding its underlying pathophysiology, genetic basis, presentations, and management. Recognizing that the clinical manifestations of HHT can involve a number of organ systems will provide clinicians with a higher index of suspicion for the disease. This early diagnosis and genotyping can greatly reduce mortality for a patient with HHT through appropriate screening for complications. This review will focus on the gastrointestinal manifestations of HHT and how these can dictate treatment and prognosis.

Massive gastric polyposis associated with a germline SMAD4 gene mutation

Juvenile polyposis syndrome (JPS) is a rare autosomal dominant disorder characterized by the development of multiple hamartomatous polyps in the gastrointestinal tract. Polyps are most common in the colorectum (98% of patients) and the stomach (14%). Causative mutations for JPS have been identified in two genes to date, SMAD4 and BMPR1A. SMAD4 mutations are associated with a higher incidence of gastric polyposis. In this case report, we describe two patients with massive gastric polyposis associated with a SMAD4 mutation. Both presented with anaemia and both had colonic polyps. Initial endoscopic findings revealed giant rugal folds suggestive of Ménétrier disease. However, as other possible gastropathies could not be differentiated on the basis of histology, a definitive diagnosis of JPS required additional mutation analysis. In patients with polyposis predominant in or limited to the stomach, establishing a diagnosis based solely on the pathological features of polyps can be challenging due to difficulties in differentiating JPS from other hypertrophic gastropathies. Mutation analysis should be considered early in the diagnostic process in cases of suspected juvenile polyposis, thus facilitating rapid diagnosis and adequate follow-up.

Genetics and Genetic Testing in Hereditary Colorectal Cancer

Colorectal cancer (CRC) remains the third most common cancer affecting men and women in the United States. Approximately one-third of CRCs are diagnosed in individuals who have family members also affected with the disease. Although the vast majority of colorectal neoplasms develop as a consequence of somatic genomic alterations arising in individual cells, approximately 5% of all CRCs arise in the setting of germline mutations in genes involved in key cellular processes. To date, multiple genes have been implicated in single-gene hereditary cancer syndromes, many of which are associated with increased risk for CRC, as well as other tumor types. This review outlines the clinical, pathologic, and genetic features of the hereditary cancer syndromes known to be associated with increased risk for CRC and delineates strategies for implementing genetic risk assessments in clinical settings.

Colonic polyps and polyposis syndromes in pediatric patients

PURPOSE OF REVIEW

Gastrointestinal polyps are commonly encountered during childhood and are one of the most common causes of rectal bleeding in this age group. Most polyps are benign and located in the colon, with the most frequent type being juvenile polyps. However, in older pediatric patients, if multiple polyps are present, in patients who have a positive family history, or if polyps are located outside of the colon, either adenomatous polyps or polyps associated with genetic abnormalities are more common.

RECENT FINDINGS

Imaging techniques such as ultrasound and computed tomographic colonoscopy have recently been utilized to identify simple juvenile colonic polyps in children with rectal bleeding in whom there is a high index of suspicion. Colonoscopy with polypectomy is still required for histologic evaluation and resection of the polyp. There have been significant advances in genetic testing and management of hereditary gastrointestinal cancer syndromes with onset in childhood or adolescence that may ultimately reduce long-term morbidity and mortality. In addition to enhanced gastrointestinal and extraintestinal malignancy screening for affected individuals, specific gene mutations within a given condition such as adenomatous polyposis coli may predict clinical course and timing of specific interventions such as colectomy. In other conditions such as phosphatase and tensin homolog hamartoma tumor syndrome, phenotype may not be predicted by genotype.

SUMMARY

Pediatricians, pediatric gastroenterologists, and adult gastroenterologists caring for children should understand how to differentiate benign polyps in the pediatric age group from those associated with a higher risk of complications including recurrence risk and risk of development of intestinal or extraintestinal malignancy. Recent advances in genetic testing, as well as development of consensus guidelines, are key in the identification, screening, and follow-up of children and adolescents with polyposis syndromes.

How to manage patients with hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia is a rare systemic autosomal dominantly inherited disorder of the fibrovascular tissue with a wide variety of clinical manifestations. Diagnosis is based on the clinical Curaçao criteria or molecular genetic testing. Dilated vessels can develop into telangiectases or larger vascular malformations in various organs, calling for an interdisciplinary approach. Epistaxis and gastrointestinal bleeding can result from these vascular defects. Various conservative and interventional treatments have been described for these conditions. However, no optimal therapy exists. Treatment can become especially difficult due to progressive anaemia or when anticoagulant or anti-thrombotic therapy becomes necessary. Screening for pulmonary arteriovenous malformations (PAVM) should be performed in all confirmed and suspected patients. Treatment by percutaneous transcatheter embolotherapy and antibiotic prophylaxis is normally effective for PAVM. Cerebral or hepatic vascular malformations and rare manifestations need to be evaluated on a case-by-case basis to determine the best course of action for treatment.

Clinical management of hereditary colorectal cancer syndromes

Hereditary factors are involved in the development of a substantial proportion of all cases of colorectal cancer. Inherited forms of colorectal cancer are usually subdivided into polyposis syndromes characterized by the development of multiple colorectal polyps and nonpolyposis syndromes characterized by the development of few or no polyps. Timely identification of hereditary colorectal cancer syndromes is vital because patient participation in early detection programmes prevents premature death due to cancer. Polyposis syndromes are fairly easy to recognize, but some patients might have characteristics that overlap with other clinically defined syndromes. Comprehensive analysis of the genes known to be associated with polyposis syndromes helps to establish the final diagnosis in these patients. Recognizing Lynch syndrome is more difficult than other polyposis syndromes owing to the absence of pathognomonic features. Most investigators therefore recommend performing systematic molecular analysis of all newly diagnosed colorectal cancer using immunohistochemical methods. The implementation in clinical practice of new high-throughput methods for molecular analysis might further increase the identification of individuals at risk of hereditary colorectal cancer. This Review describes the clinical management of the various hereditary colorectal cancer syndromes and demonstrates the advantage of using a classification based on the underlying gene defects.

MicroRNA-26b inhibits epithelial-mesenchymal transition in hepatocellular carcinoma by targeting USP9X

BACKGROUND

Metastasis is responsible for the rapid recurrence and poor survival of malignancies. Epithelial-mesenchymal transition (EMT) has a critical role in metastasis. Increasing evidence indicates that EMT can be regulated by microRNAs (miRNAs). The aim of this study was to investigate the role of miR-26b in modulating epithelial-mesenchymal transition (EMT) in hepatocellular carcinoma (HCC), as well as to identify its underlying mechanism of action.

METHODS

The expression level of miR-26b was assessed in multiple HCC cell lines (HepG2, MHCC97H, Hep3B, MHCC97L, HCCC9810, BEL-7402, Huh7 and QGY-7703), as well as in liver tissue from patients with HCC. Follow-up studies examined the effects of a miR-26b mimic (increased expression) and a miR-26b inhibitor (decreased expression) on markers of EMT, wound healing and cell migration. The molecular target of miR-26b was also identified using a computer algorithm and confirmed experimentally.

RESULTS

MiR-26b expression was decreased in HCC cell lines and was inversely correlated with the grade of HCC. Increased expression of miR-26b inhibited the migration and invasiveness of HCC cell lines, which was accompanied by decreased expression of the epithelial marker E-cadherin and increased expression of the mesenchymal marker vimentin, at both the mRNA and protein expression levels. A binding site for miR-26b was theoretically identified in the 3'UTR of USP9X. Further studies revealed that overexpression of miR-26b repressed the endogenous level of USP9X protein expression. Overexpression of miR-26b also repressed Smad4 expression, whereas its inhibition elevated Smad4 expression.

CONCLUSIONS

Taken together, our results indicate that miR-26b were inhibited in HCC. In HCC cell lines, miR-26b targeted the 3'UTR of USP9X, which in turn affects EMT through Smad4 and the TGF-β signaling pathway. Our analysis of clinical HCC samples verifies that miR-26b also targets USP9X expression to inhibit the EMT of hepatocytes. Thus, miR-26b may have some effects on the EMT of HCC cells.

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.

Colorectal polyps and polyposis syndromes

A polyp is defined as any mass protruding into the lumen of a hollow viscus. Colorectal polyps may be classified by their macroscopic appearance as sessile (flat, arising directly from the mucosal layer) or pedunculated (extending from the mucosa through a fibrovascular stalk). Colorectal polyps may also be histologically classified as neoplastic or as non-neoplastic (hyperplastic, hamartomatous, or inflammatory). The neoplastic polyps are of primary importance because they harbor a malignant potential, which represents a stage in the development of colorectal cancer. For this reason, it is essential to identify these polyps at a sufficiently early stage, when a simple outpatient procedure to remove them can interrupt the development of colorectal cancer and prevent disease and death. When invasive carcinoma arises in a polyp, careful consideration must be given to ensuring the adequacy of treatment. Although most neoplastic polyps do not evolve into cancer, it is well accepted that the majority of colorectal carcinomas evolve from adenomatous polyps; the sequence of events leading to this transformation is referred to as the adenoma-to-carcinoma sequence.

The presence of a systemic process that promotes the development of multiple gastro-intestinal polyps is termed ‘polyposis’. Hereditary gastro-intestinal polyposis syndromes account for approximately 1% of all cases of colorectal cancer and are associated with a broad spectrum of extra-colonic tumors. Early detection and accurate classification of these syndromes are essential, in order to initiate a surveillance program for the early detection of cancer. Several polyposis syndromes have been described, each having its own genetic basis and characteristic polyp distribution, clinical presentation, and malignancy risk.

Diagnostic modalities and treatment options for neoplastic polyps—as well as the most prevalent polyposis syndromes—are reviewed below.

Specific cancer rates may differ in patients with hereditary haemorrhagic telangiectasia compared to controls

Background

Hereditary haemorrhagic telangiectasia (HHT) is inherited as an autosomal dominant trait, affects ~1 in 5,000, and causes multi-systemic vascular lesions and life-limiting complications. Life expectancy is surprisingly good, particularly for patients over 60ys. We hypothesised that individuals with HHT may be protected against life-limiting cancers.

Methods

To compare specific cancer rates in HHT patients and controls, we developed a questionnaire capturing data on multiple relatives per respondent, powered to detect differences in the four most common solid non skin cancers (breast, colorectal, lung and prostate), each associated with significant mortality. Blinded to cancer responses, reports of HHT-specific features allowed assignment of participants and relatives as HHT-subjects, unknowns, or controls. Logistic and quadratic regressions were used to compare rates of specific cancer types between HHT subjects and controls.

Results

1,307 participants completed the questionnaire including 1,007 HHT-subjects and 142 controls. The rigorous HHT diagnostic algorithm meant that 158 (12%) completed datasets were not assignable either to HHT or control status. For cancers predominantly recognised as primary cancers, the rates in the controls generally matched age-standardised rates for the general population. HHT subjects recruited through the survey had similar demographics to controls, although the HHT group reported a significantly greater smoking habit. Combining data of participants and uniquely-reported relatives resulted in an HHT-arm of 2,161 (58% female), and control-arm of 2,817 (52% female), with median ages of 66ys [IQR 53–77] and 77ys [IQR 65–82] respectively. In both crude and age-adjusted regression, lung cancers were significantly less frequent in the HHT arm than controls (age-adjusted odds ratio 0.48 [0.30, 0.70], p = 0.0012). Breast cancer prevalence was higher in HHT than controls (age-adjusted OR 1.52 [1.07, 2.14], p = 0.018). Overall, prostate and colorectal cancer rates were equivalent, but the pattern of colorectal cancer was modified, with a higher prevalence in younger HHT patients than controls.

Conclusions

These preliminary survey data suggest clinically significant differences in the rates of lung, breast and colorectal cancer in HHT patients compared to controls. For rare diseases in which longitudinal studies take decades to recruit equivalent datasets, this type of methodology provides a good first-step method for data collection.

Familial juvenile polyposis syndrome with a novel SMAD4 germline mutation

Juvenile polyposis syndrome (JPS) is a dominantly inherited disorder characterized by the development of numerous juvenile polyps (JPs) of the gastrointestinal tract, and associated with a mutation of the SMAD4 or BMPR1A gene. Here, we report a mother-daughter case of familial JPS. A 29-year-old female patient with severe iron deficiency anemia and hypoproteinemia had numerous polyps in the stomach and a few polyps in the ileum and colon that were detected endoscopically. Biopsy specimens from the gastric polyps were diagnosed as JPs. The patient underwent a laparoscopy-assisted total gastrectomy, and her anemia and hypoproteinemia improved. Her mother also had multiple JPs in the stomach, duodenum, jejunum, and colon. We then diagnosed them as having familial JPS. Moreover, germline mutation analysis of the 2 patients presented a novel pathogenic SMAD4 variant.