mTOR inhibitors reduce enteropathy, intestinal bleeding and colectomy rate in patients with juvenile polyposis of infancy with PTEN-BMPR1A deletion

Genetic predisposition to gastrointestinal polyposis: syndromes, tumour features, genetic testing, and clinical management

Gastrointestinal tract polyposis is characterised by the presence of multiple polyps, particularly in the colorectum, and encompasses both cancer predisposition genetic syndromes and non-syndromic clinical manifestations. The sources of the heterogeneity observed in polyposis syndromes relate to genetic cause, mode of inheritance, polyp burden and histological type, and spectrum and frequency of extracolonic manifestations. These features determine the clinical management of carriers, including strategies for cancer prevention and early detection, and oncological treatments. Despite substantial progress in identifying the genetic causes of polyposis, a large proportion of cases remain genetically unexplained. Although some of these cases might be due to lifestyle, environmental factors, or cancer treatments, it is likely that additional polyposis predisposition genes will be identified. This Review provides an overview of the known syndromes and genes, genetic testing, and clinical management of patients with polyposis, and recent advances and challenges in the field of gastrointestinal polyposis.

Chemoprevention in hereditary digestive neoplasia: A comprehensive review

Hereditary syndromes, such as familial adenomatous polyposis (FAP), MUTYH polyposis or Lynch syndrome, are particularly predisposing to the development of colorectal cancer. These situations have necessitated the development of adapted prevention strategies based largely on reinforced endoscopic surveillance and the search for complementary prevention strategies. This is the case for chemoprevention, which is the long-term administration of chemical agents limiting carcinogenesis, used as primary or secondary prophylaxis. The aim of this review is to present the available literature and the latest advances in chemoprevention in patients with FAP or MUTYH and other polyposis as well as in patients with Lynch syndrome. The main conclusions of the few available guidelines in these situations are also discussed.

Left ventricular assist devices promote changes in the expression levels of platelet microRNAs

Introduction

MicroRNAs (miRs) emerged as promising diagnostic and therapeutic biomarkers in cardiovascular diseases. The potential clinical utility of platelet miRs in the setting of left ventricular assist device (LVAD) support is unexplored.

Methods

We prospectively measured the expression levels of 12 platelet miRs involved in platelet activation, coagulation, and cardiovascular diseases in LVAD patients by quantitative real-time polymerase chain reaction. Data were longitudinally measured before LVAD implant and after 1, 6, and 12 months of LVAD support, and compared with those measured in healthy volunteers (controls). In silico analysis was also performed to identify pathways targeted by differentially expressed miRs.

Results

Data from 15 consecutive patients and 5 controls were analyzed. Pre-implant expression levels of platelet miR-126, miR-374b, miR-223, and miR-320a were significantly different in patients vs. controls. The expression levels of platelet miR-25, miR-144, miR-320, and miR-451a changed significantly over the course of LVAD support; in silico analysis revealed that these miRs are implicated in both cardiac- and coagulation-associated pathways. Furthermore, the patients who suffered from bleeding (n = 5, 33%) had significantly higher pre-implant expression levels of platelet miR-151a and miR-454 with respect to the patients who did not. The same miRs were also differentially expressed in bleeders following LVAD implantation early before the clinical manifestation of the events.

Discussion

This study provides a proof-of-concept evidence of significant modulation of platelet miRs expression driven by LVADs. The possible existence of a platelet miRs signature predictive of the development of bleeding events warrants further validation studies.

Updates in the diagnosis and management of non-ampullary small-bowel polyposis

Advances in endoscopic instruments and techniques changed the strategy of diagnosis and management for non-ampullary small-bowel polyposis. In patients with Peutz-Jeghers syndrome, gastrointestinal surveillance using capsule endoscopy should commence no later than eight years old. Small bowel polyps >15 mm should be treated to prevent intussusception. Recently, endoscopic ischemic polypectomy and endoscopic reduction of intussusception were described. In patients with familial adenomatous polyposis, the first endoscopic screening using a lateral viewing and a longer endoscope to check the proximal jejunum should be performed around 25 years. Some experts recommend a first duodenal examination with a first colonoscopy (13 years). The surveillance intervals for duodenal polyposis should be adjusted individually. ESGE recommended the resection of every adenoma larger than 1 cm. Cold snare polypectomy has the potential to change the threshold of size for endoscopic resection. In patients with Juvenile polyposis syndrome, small bowel involvement seems infrequent and mostly located in the duodenal part. There is no indication for distal small bowel investigation.

Polyps and Polyposis Syndromes in Children: Novel Endoscopic Considerations

Polypectomy is the most common therapeutic endoscopic intervention in children. Management of sporadic juvenile polyps is limited to polypectomy to resolve symptoms, whereas polyposis syndromes pose a multidisciplinary challenge with broader ramifications. In preparation for polypectomy, there are key patient, polyp, endoscopy unit, and provider characteristics that factor into the likelihood of success. Younger age and multiple medical comorbidities increase the risk of adverse outcomes, classified as intraoperative, immediate postoperative, and delayed postoperative complications. Novel techniques, including cold snare polypectomy, can significantly decrease adverse events but a more structured training process for polypectomy in pediatric gastroenterology is needed.

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.

Tumor predisposition: what's the skin got to do with it?

PURPOSE OF REVIEW

Recognition of skin findings associated with tumor predisposition syndromes can prompt early evaluation and surveillance and improve management. Additionally, knowing when to test and when to defer performing genetic testing can streamline management. This article reviews tumor predisposition syndromes with recently characterized skin findings and disorders for which early recognition and counseling can impact the course of disease.

RECENT FINDINGS

Café au lait macules (CALMs) are important in many tumor predisposition syndromes, and 'atypical' CALMs are associated with constitutional mismatch repair deficiency and Fanconi anemia. Melanoma predisposition syndromes caused by pathogenic variants in POT1 and BAP1 are more recently described, and both are associated with Spitzoid tumors. Somatic pathogenic variants can cause segmental nevoid basal cell carcinoma syndrome and a mosaic form of Peutz-Jeghers syndrome. Patients with PTEN hamartoma syndrome have increased risk for melanoma but this might not occur until adulthood.

SUMMARY

The cutaneous manifestations of tumor predisposition syndromes can aid diagnosis. Early photoprotection is key to modifying a main risk factor for skin cancer in many of these syndromes. Implementing surveillance guidelines facilitates early detection of tumors.

Chemoprevention Considerations in Patients with Hereditary Colorectal Cancer Syndromes

Secondary prevention of colorectal neoplasia with chemoprevention is long-studied area of research and clinical use in patients with the 2 most common hereditary colorectal cancer syndromes including Lynch syndrome and familial adenomatous polyposis. No medication is currently approved for use for the prevention of colorectal polyps or cancer in either the general population or individuals with the hereditary colorectal cancer syndromes. Emerging data in animal models and limited data in humans suggest vaccines may be the next breakthrough for neoplasia prevention in patients with hereditary colorectal cancer. Clinicians must acknowledge chemoprevention is an adjunct and does not supplant endoscopic surveillance.

Paediatric polyposis syndromes: burden of disease and current concepts

PURPOSE OF REVIEW

Polyposis syndromes are rare but significant entities that often present during childhood and adolescence. Polyposis syndromes should remain high on the differential diagnoses for any child presenting with rectal bleeding, protein-losing enteropathy or intussusception in the setting of multiple polyps in the gastrointestinal tract. There are three primary paediatric polyposis syndromes: Juvenile polyposis syndrome (JPS), Familial adenomatous polyposis (FAP) and Peutz-Jeghers syndrome (PJS). This review will cover recent guidelines for these conditions and advances in genetic testing.

RECENT FINDINGS

The first set of paediatric guidelines were released in 2019 by the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) for FAP, JPS and PJS. Even with advances in genetic testing, a significant proportion of patients with polyposis syndromes have no identifiable genetic mutations. Recent research has shown that polyps behave differently in patients with and without disease-causing variants, emphasizing the role of genetic testing in the diagnosis and management of polyposis syndromes.

SUMMARY

Polyposis syndromes in the paediatric population are growing due to increased recognition and advances in genetic testing. A timely diagnosis and surveillance of a paediatric polyposis syndrome are pivotal for the management of disease burden and early identification of cancers within the gastrointestinal tract and beyond. Paediatricians, paediatric gastroenterologists, paediatric oncologists and paediatric surgeons should be familiar with the presentation and comorbidities of polyposis syndromes in children and adolescents. Further research into genotype-phenotype correlations is needed to tailor the care for paediatric patients with polyposis syndromes.