Hamartomatous polyposis syndromes

LKB1 loss promotes colorectal cancer cell metastasis through regulating TNIK expression and actin cytoskeleton remodeling

Colorectal cancer (CRC) is one of the most common malignant tumors. Approximately 5%-6% of CRC cases are associated with hereditary CRC syndromes, including the Peutz-Jeghers syndrome (PJS). Liver kinase B1 (LKB1), also known as STK11, is the major gene responsible for PJS. LKB1 heterozygotic deficiency is involved in intestinal polyps in mice, while the mechanism of LKB1 in CRC remains elusive. In this study, we generated LKB1 knockout (KO) CRC cell lines by using CRISPR-Cas9. LKB1 KO promoted CRC cell motility in vitro and tumor metastases in vivo. LKB1 attenuated expression of TRAF2 and NCK-interacting protein kinase (TNIK) as accessed by RNA-seq and western blots, and similar suppression was also detected in the tumor tissues of azoxymethane/dextran sodium sulfate-induced intestinal-specific LKB1-KO mice. LKB1 repressed TNIK expression through its kinase activity. Moreover, attenuating TNIK by shRNA inhibited cell migration and invasion of CRC cells. LKB1 loss-induced high metastatic potential of CRC cells was depended on TNIK upregulation. Furthermore, TNIK interacted with ARHGAP29 and further affected actin cytoskeleton remodeling. Taken together, LKB1 deficiency promoted CRC cell metastasis via TNIK upregulation and subsequently mediated cytoskeleton remodeling. These results suggest that LKB1-TNIK axis may play a crucial role in CRC progression.

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

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

Strong Hereditary Predispositions to Colorectal Cancer

Cancer is one of the most common causes of death worldwide. A strong predisposition to cancer is generally only observed in colorectal cancer (5% of cases) and breast cancer (2% of cases). Colorectal cancer is the most common cancer with a strong genetic predisposition, but it includes dozens of various syndromes. This group includes familial adenomatous polyposis, attenuated familial adenomatous polyposis, MUTYH-associated polyposis, NTHL1-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, Lynch syndrome, and Muir-Torre syndrome. The common symptom of all these diseases is a very high risk of colorectal cancer, but depending on the condition, their course is different in terms of age and range of cancer occurrence. The rate of cancer development is determined by its conditioning genes, too. Hereditary predispositions to cancer of the intestine are a group of symptoms of heterogeneous diseases, and their proper diagnosis is crucial for the appropriate management of patients and their successful treatment. Mutations of specific genes cause strong colorectal cancer predispositions. Identifying mutations of predisposing genes will support proper diagnosis and application of appropriate screening programs to avoid malignant neoplasm.

Endoscopic Findings in Patients With PTEN Hamartoma Tumor Syndrome Undergoing Surveillance

GOALS AND BACKGROUND

Phosphatase and tensin homolog hamartoma tumor syndrome (PHTS) is an inherited disorder that increases the risk for cancer in multiple organ systems, including breast, endometrial, thyroid, and the gastrointestinal tract. Surveillance is recommended however there lacks data to describe the change in polyposis phenotype and cancer incidence over surveillance. Our aim is to describe the polyposis phenotype and cancer incidence in PHTS patients undergoing endoscopic surveillance.

STUDY

PHTS patients, ages 17 through 89, who underwent at least 2 esophagogastroduodenoscopy (EGDs) or colonoscopies were identified. Number and sizes of polyps were noted, from which 5 categories were recreated. Incidence of colorectal and gastric cancer was evaluated.

RESULTS

Seventy patients were included. Patients were clustered and classified into 1 of 5 categories: no polyps, few small polyps (<1 cm, < 10 polyps), few large polyps (≥1 cm, < 10 polyps), many small polyps (<1 cm, ≥10 polyps), many large polyps (≥1 cm, ≥10 polyps). There was no significant difference in polyp number or size on EGD (P=0.47 and 0.83, respectively) or colonoscopy (P=0.49 and 0.10, respectively) over the surveillance period (4.8±3.9 y for stomach and 5.6±4.4 y for colon). The average interval between endoscopies was 28±24 months for EGDs and 29±23 months for colonoscopies. A stage II transverse colon adenocarcinoma and stage IV gastric adenocarcinoma were identified. Standardized incidence rates for gastric and colon cancers were 5427 (P=0.0002) and 353 (P=0.002), respectively.

CONCLUSIONS

PTHS individuals can be classified into polyposis phenotypes which do not change over an endoscopic surveillance period. Two cancers were associated with a large size polyp phenotype. Surveillance intervals should be determined by polyp size ≥1 cm and pathology.

Unusual manifestations of Peutz-Jegher's syndrome in children

PeutzJegher's syndrome (PJS) is a rare, autosomal dominant disease, characterized by gastrointestinal (GI) polyps and perioral hyperpigmentation along with the increased risk of certain malignancies. In children, the most common presentation is recurrent intussusception due to polyps. These polyps can involve any part of the GI tract and can present with a variety of clinical presentations. Usually, these polyps can be removed endoscopically but often require surgical excision also. In this report, we discuss two children of PJS with uncommon presentations, one presented with retrograde intussusception and another with gastric outlet obstruction. The first child underwent laparoscopy and another required open surgery with intraoperative enteroscopy.

Peutz-Jeghers Syndrome and the Role of Imaging: Pathophysiology, Diagnosis, and Associated Cancers

Simple Summary

The Peutz-Jeghers Syndrome is a rare autosomal dominant syndrome characterized by mucocutaneous pigmentations, multiple gastrointestinal hamartomatous polyps, and an elevated risk of malignancy. Awareness of various Peutz-Jeghers Syndrome imaging patterns, associated malignancies, and their complications is crucial for accurate imaging interpretation and patient management. In this manuscript, we provide an overview of this condition, associated malignancies, and imaging surveillance protocols.

Abstract

The Peutz-Jeghers Syndrome (PJS) is an autosomal dominant neoplastic syndrome defined by hamartomatous polyps through the gastrointestinal tract, development of characteristic mucocutaneous pigmentations, and an elevated lifetime cancer risk. The majority of cases are due to a mutation in the STK11 gene located at 19p13.3. The estimated incidence of PJS ranges from 1:50,000 to 1:200,000. PJS carries an elevated risk of malignancies including gastrointestinal, breast, lung, and genitourinary (GU) neoplasms. Patients with PJS are at a 15- to 18-fold increased malignancy risk relative to the general population. Radiologists have an integral role in the diagnosis of these patients. Various imaging modalities are used to screen for malignancies and complications associated with PJS. Awareness of various PJS imaging patterns, associated malignancies, and their complications is crucial for accurate imaging interpretation and patient management. In this manuscript, we provide a comprehensive overview of PJS, associated malignancies, and surveillance protocols.

Appendiceal carcinoid in a pediatric patient with Peutz-Jeghers syndrome: A case report and comprehensive literature review

RATIONALE

Peutz-Jeghers syndrome (PJS), a rare autosomal dominant disorder, is characterized by mucocutaneous pigmentations, hamartomatous polyps in the gastrointestinal tract, and a high risk of developing various malignancies. To the best of our knowledge, only 1 case of appendiceal carcinoid associated with PJS has been previously reported in the pediatric population.

PATIENT CONCERNS

We report a 7-year-old girl who was admitted for severe, intermittent abdominal pain and cramps, nausea, and vomiting. Multiple brown melanotic macules on the lips, buccal mucosa, and the tongue were noted.

DIAGNOSIS

A plain abdominal X-ray in a standing position revealed dilated intestinal loops with multiple air-fluid levels. A computed tomography scan of the abdomen showing a "coffee bean" appearance of the jejunal loop with a transition point to the duodenal loop. Axial-contrast-enhanced computed tomography scan of the abdomen showing dilated jejunum loops, filled with fluid with the swirled appearance of mesentery typical for volvulus. The diagnosis of PJS was based on clinical findings along with the histopathologic confirmation of the hamartomatous polyps.

INTERVENTIONS

An emergency laparotomy was performed, revealing a jejunojejunal intussusception starting 40 cm from the duodenojejunal flexure. Jejunotomy revealed that a lead-point intussusception was a necrotic hamartomatous polyp. After resecting the involved jejunal necrotic segment, including the polyp, end-to-end jejuno-jejunal anastomosis was performed. Further exploration revealed the presence of a jejunal mass 80 cm from the duodenojejunal flexure identified as another hamartomatous pedunculated polyp. The polyp was resected, and the enterotomy was then closed transversely. The grossly normal appendix was also removed.

OUTCOMES

Clinical findings along with the histopathologically confirmed hamartomatous polyps were consistent with PJS. An appendiceal carcinoid (well-differentiated neuroendocrine tumor, European Neuroendocrine Tumor Society stage pT2) was incidentally detected during histological examination of the appendix. The patient and parents were counseled accordingly, focusing on active surveillance and control of symptoms. Two additional hamartomatous polyps (gastric and jejunal) were detected endoscopically and resected in the fourth postoperative week. A regular, 1-year follow-up and surveillance revealed no complications or recurrences.

LESSONS

Unusual neoplasms can occasionally be encountered in well-defined syndromes such as PJS. Therefore, active follow-up and surveillance are mandatory for all patients with PJS.

A PTEN variant uncouples longevity from impaired fitness in Caenorhabditis elegans with reduced insulin/IGF-1 signaling

Insulin/IGF-1 signaling (IIS) regulates various physiological aspects in numerous species. In Caenorhabditis elegans, mutations in the daf-2/insulin/IGF-1 receptor dramatically increase lifespan and immunity, but generally impair motility, growth, and reproduction. Whether these pleiotropic effects can be dissociated at a specific step in insulin/IGF-1 signaling pathway remains unknown. Through performing a mutagenesis screen, we identified a missense mutation daf-18(yh1) that alters a cysteine to tyrosine in DAF-18/PTEN phosphatase, which maintained the long lifespan and enhanced immunity, while improving the reduced motility in adult daf-2 mutants. We showed that the daf-18(yh1) mutation decreased the lipid phosphatase activity of DAF-18/PTEN, while retaining a partial protein tyrosine phosphatase activity. We found that daf-18(yh1) maintained the partial activity of DAF-16/FOXO but restricted the detrimental upregulation of SKN-1/NRF2, contributing to beneficial physiological traits in daf-2 mutants. Our work provides important insights into how one evolutionarily conserved component, PTEN, can coordinate animal health and longevity.

Peutz-Jeghers syndrome

PURPOSE OF REVIEW

Peutz-Jeghers syndrome is a rare, autosomal dominant, hereditary polyposis syndrome defined by gastrointestinal hamartomas and mucocutaneous pigmentations, caused by a germline mutation in the serine/ threonine kinase 11 or liver kinase B1 (STK11/LKB1) genes. Hamartomatous polyps located throughout the gastrointestinal tract can be complicated by bleeding and small bowel intussusception, potentially leading to the need for emergency surgery. Individuals suffering from Peutz-Jeghers syndrome have an increased lifetime risk of various forms of cancer (gastrointestinal, pancreatic, lung, breast, uterine, ovarian and testicular). Surveillance should lead to the prevention of complications and thus a reduction in mortality and morbidity of patients.

RECENT FINDINGS

A combined approach based on wireless capsule endoscopy, magnetic resonance enterography and device-assisted enteroscopy is effective in reduction of the polyp burden and thus decreasing the risk of bleeding and intussusception. Current guidelines for screening and surveillance are mostly based on expert opinion rather than evidence.

SUMMARY

Peutz-Jeghers syndrome is an emerging disease that significantly affects the quality of life enjoyed by patients. Despite of all the progress in improved early diagnostics, options for advanced endoscopic therapy and elaborate surveillance, acute and chronic complications decrease the life expectancy of patients suffering from Peutz-Jeghers syndrome.

Small Bowel Epithelial Precursor Lesions: A Focus on Molecular Alterations

The wider use of gastrointestinal endoscopic procedures has led to an increased detection of small intestinal preneoplastic and neoplastic epithelial lesions, most of which are identified in the duodenum and ampullary region. Like their malignant counterparts, small intestinal glandular precursor lesions, which include adenomas and hamartomas, may arise sporadically or be associated with hereditary tumor syndromes, such as familial adenomatous polyposis, MUTYH-associated polyposis, Lynch syndrome, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and Cowden syndrome. In addition, dysplastic, preinvasive lesions have been observed adjacent to small bowel adenocarcinomas complicating immune-related disorders, such as celiac or Crohn’s disease. Adenomatous lesions may exhibit an intestinal-type, gastric-type, or, very rarely, serrated differentiation, related to different molecular pathogenetic mechanisms. Finally, in the background of multiple endocrine neoplasia 1 syndrome, precursor neuroendocrine growths have been described. In this review we offer a comprehensive description on the histo-molecular features of the main histotypes of small bowel epithelial precursors lesions, including: (i) sporadic adenomas (intestinal-type and gastric-type; non-ampullary and ampullary); (ii) syndromic adenomas; (iii) small bowel dysplasia in celiac and Crohn’s disease; (iv) serrated lesions; (v) hamartomatous lesions; and (vi) neuroendocrine precursor lesions.

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

Ultra-rare genetic disorders can provide proof of concept for efficacy of targeted therapeutics and reveal pathogenic mechanisms relevant to more common conditions. Juvenile polyposis of infancy (JPI) is caused by microdeletions in chromosome 10 that result in haploinsufficiency of two tumor suppressor genes: phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and bone morphogenetic protein receptor type IA (BMPR1A). Loss of PTEN and BMPR1A results in a much more severe phenotype than deletion of either gene alone, with infantile onset pan-enteric polyposis and a high mortality rate. No effective pharmacological therapy exists. A multi-center cohort analysis was performed to characterize phenotype and investigate the therapeutic effect of mammalian target of rapamycin (mTOR) inhibition (adverse events, disease progression, time to colectomy and mortality) in patients with JPI. Among 25 JPI patients identified (mean age of onset 13 months), seven received mTOR inhibitors (everolimus, n = 2; or sirolimus, n = 5). Treatment with an mTOR inhibitor reduced the risk of colectomy (hazard ratio = 0.27, 95% confidence interval = 0.07-0.954, P = 0.042) and resulted in significant improvements in the serum albumin level (mean increase = 16.3 g/l, P = 0.0003) and hemoglobin (mean increase = 2.68 g/dl, P = 0.0077). Long-term mTOR inhibitor treatment was well tolerated over an accumulated follow-up time of 29.8 patient years. No serious adverse events were reported. Early therapy with mTOR inhibitors offers effective, pathway-specific and personalized treatment for patients with JPI. Inhibition of the phosphoinositol-3-kinase-AKT-mTOR pathway mitigates the detrimental synergistic effects of combined PTEN-BMPR1A deletion. This is the first effective pharmacological treatment identified for a hamartomatous polyposis syndrome.

The Inherited and Familial Component of Early-Onset Colorectal Cancer

Early-onset colorectal cancer (EOCRC), defined as that diagnosed before the age of 50, accounts for 10–12% of all new colorectal cancer (CRC) diagnoses. Epidemiological data indicate that EOCRC incidence is increasing, despite the observed heterogeneity among countries. Although the cause for such increase remains obscure, ≈13% (range: 9–26%) of EOCRC patients carry pathogenic germline variants in known cancer predisposition genes, including 2.5% of patients with germline pathogenic variants in hereditary cancer genes traditionally not associated with CRC predisposition. Approximately 28% of EOCRC patients have family history of the disease. This article recapitulates current evidence on the inherited syndromes that predispose to EOCRC and its familial component. The evidence gathered support that all patients diagnosed with an EOCRC should be referred to a specialized genetic counseling service and offered somatic and germline pancancer multigene panel testing. The identification of a germline pathogenic variant in a known hereditary cancer gene has relevant implications for the clinical management of the patient and his/her relatives, and it may guide surgical and therapeutic decisions. The relative high prevalence of hereditary cancer syndromes and familial component among EOCRC patients supports further research that helps understand the genetic background, either monogenic or polygenic, behind this increasingly common disease.

Diagnostic difficulty in Peutz–Jeghers syndrome

A case of diagnostic difficulty facing the patient with colonic polyposis secondary to Peutz–Jeghers syndrome, but without family history and pathognomonic clinical features of the disease, is illustrated. The exams, including biopsy, led to diagnostic uncertainty and the definitive diagnosis was characterized in therapeutic of exception.

An unusual presentation revealing Peutz-Jeghers syndrome in adult

Introduction

Peutz-Jeghers syndrome (PJS) is a rare hereditary disease characterized by hyperpigmentation on the lips and oral cavity and gastrointestinal hamartomatous polyps. The most common complications in PJS patients are bleeding, bowel obstruction and intussusception.

Presentation of case

We hereby report a case of a 33-year-old female, without a family history of the disease, who presented to the emergency room with acute abdominal pain, bloating and not passing gas. On abdominal examination, upper abdominal and periumbilical tenderness was found. Computed tomography (CT) of the abdomen demonstrated suspected ascending colon intussusception. The patient underwent a mid-line laparotomy that showed an ileocolic intussusception. Reduction of this intussusception was successfully done with resection of the affected segment that showed presence of two pedunculated polyps. The specimen was sent thereafter to our department for histopathological evaluation, which confirmed the diagnosis of hamartomatous Peutz-Jeghers polyps with no malignancy. Afterwards, the patient was carefully reexamined and the physical examination revealed multiple pigmented spots on the face and lips. Thus, the diagnosis of Peutz-Jeghers syndrome was made.

Discussion

PJS is a rare autosomal dominant disorder that often remain undiagnosed for many years. Acute complications such as intestinal obstruction secondary to intussusception is one of infrequent revealing symptoms.

Conclusion

Early identification, in patients with PJS and family members, as well as close cancer surveillance can improve certainly prognosis in these individuals.

The missing heritability of familial colorectal cancer

Pinpointing heritability factors is fundamental for the prevention and early detection of cancer. Up to one-quarter of colorectal cancers (CRCs) occur in the context of familial aggregation of this disease, suggesting a strong genetic component. Currently, only less than half of the heritability of CRC can be attributed to hereditary syndromes or common risk loci. Part of the missing heritability of this disease may be explained by the inheritance of elusive high-risk variants, polygenic inheritance, somatic mosaicism, as well as shared environmental factors, among others. A great deal of the missing heritability in CRC is expected to be addressed in the coming years with the increased application of cutting-edge next-generation sequencing technologies, routine multigene panel testing and tumour-focussed germline predisposition screening approaches. On the other hand, it will be important to define the contribution of environmental factors to familial aggregation of CRC incidence. This review provides an overview of the known genetic causes of familial CRC and aims at providing clues that explain the missing heritability of this disease.

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.

Les cancers colorectaux héréditaires vus par le pathologiste

The pathologist's role in the management of hereditary colorectal cancer is important. The pathologist may suspect a familial cancer when particular morphological and/or clinical criteria are present or give a response to a clinical request in the context of a possible hereditary cancer. In this setting, the pathologist's conclusions have necessarily to be integrated to a precise environment, and if needed, followed by an oncogenetic consultation and a germline mutation research. The aim of this article is to present the main aspects of hereditary colon cancers that a pathologist may see, but also to highlight the histopathological characteristics and the place of the pathologist in the management of these different entities.

Sporadic Peutz-Jeghers syndrome: a rare cause of intussusception in a toddler with no medical history

Peutz–Jeghers syndrome (PJS) is an unusual hamartomatous polyposis of the gastrointestinal tract associated with melanocytic mucocutaneous hyperpigmentation. This research paper examines the case of an 18-month-old Syrian female who had been diagnosed with intussusception. The patient underwent laparotomy, and multiple small bowel polyps were found to act as the lead point. For this reason, small bowel resection (~15 cm), with end-to-end anastomosis, were performed. Although PJS diagnosis was histopathologically confirmed, the patient had no pigmented lesions on the face, the lower lip or the buccal mucosa and neither had any history of hospitalization or family history of the disease. This case was examined and is reported in the present study because PJS is rarely present at this early age when significant medical history is lacking.

Early onset Peutz-Jeghers syndrome, the importance of appropriate diagnosis and follow-up: A case report

RATIONALE

Peutz-Jeghers syndrome (PJS) is currently defined as an inherited condition, also called a familial hamartomatous polyposis syndrome, characterized by the association between pigmented mucocutaneous lesions and hamartomatous polyps in the gastrointestinal tract, especially in the small bowel.

PATIENT CONCERNS

We present the case of a 7-year-old male patients, diagnosed at the age of 3 years with PJS due to a surgical intervention for acute abdominal pain that revealed a rectal polyp associated with hyperpigmented maculae on the lips and oral mucosa. His family history revealed the same condition in his mother, who was diagnosed much later, at the age of 25 years.

DIAGNOSES

The upper and lower digestive endoscopy revealed multiple polyps of different sizes within the stomach, and 2 polyps at 5 cm from the anal orifice. The barium enterography revealed 3 polyps within the ileum.

INTERVENTIONS

We administered blood transfusions and both recto-anal polyps were surgically removed.

OUTCOMES

The outcome was favorable and the patient was discharged with the recommendations for clinical assessment at least every 6 months, annual laboratory tests, but also follow-up of the detected polyps and screening by upper digestive endoscopy, barium enterography and colonoscopy every 2 years.

LESSONS

Early onset of PJS presenting with polys is quite rare since they require time for their development manifesting usually after the first decade of life. Close monitoring is essential for PJS in order to prevent potential complications and early detect the development of related malignancies.

Genetic predisposition to colorectal cancer: syndromes, genes, classification of genetic variants and implications for precision medicine

This article reviews genes and syndromes associated with predisposition to colorectal cancer (CRC), with an overview of gene variant classification. We include updates on the application of preventive and therapeutic measures, focusing on the use of non-steroidal anti-inflammatory drugs (NSAIDs) and immunotherapy. Germline pathogenic variants in genes conferring high or moderate risk to cancer are detected in 6-10% of all CRCs and 20% of those diagnosed before age 50. CRC syndromes can be subdivided into nonpolyposis and polyposis entities, the most common of which are Lynch syndrome and familial adenomatous polyposis, respectively. In addition to known and novel genes associated with highly penetrant CRC risk, identification of pathogenic germline variants in genes associated with moderate-penetrance cancer risk and/or hereditary cancer syndromes not traditionally linked to CRC may have an impact on genetic testing, counseling, and surveillance. The use of multigene panels in genetic testing has exposed challenges in the classification of variants of uncertain significance. We provide an overview of the main classification systems and strategies for improving these. Finally, we highlight approaches for integrating chemoprevention in the care of individuals with genetic predisposition to CRC and use of targeted agents and immunotherapy for treatment of mismatch repair-deficient and hypermutant tumors. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Intramucosal lipomas of the colon implicate Cowden syndrome

Intramucosal lipomas are rare and easily overlooked by pathologists, despite their diagnostic significance for Cowden syndrome (PTEN hamartoma tumor syndrome), an inherited multiorgan cancer syndrome. Only 25-35% of patients harbor identifiable PTEN mutations, thus clinical features, like intramucosal lipomas, remain the mainstay of diagnosis. The significance and diagnostic approach to intramucosal lipomas have not been thoroughly addressed in the literature. Intramucosal lipomas are mimicked by pseudolipomatosis coli, an artifactual mucosal gas infiltration from endoscopic insufflation. This differential was investigated by morphology and S-100 immunohistochemistry. Twenty-five colonic intramucosal lipomas were identified from 176 archival gastrointestinal lipomas from 1998 to 2017. Controls included 40 submucosal lipomas and 30 pseudolipomatoses. S-100 immunohistochemistry on all 95 lesions confirmed delicate fat vacuole membranous and nuclear S-100 staining in lipomas absent from pseudolipomatoses. Differentiating morphology between intramucosal lipoma and pseudolipomatosis, respectively, included consistently large, regular fat vacuoles (92% vs 7%), associated spindle cells (80% vs 0%), and mucosal lymphoid aggregate involvement (12% vs 80%). Of the 25 intramucosal lipomas, five patients (20%) had confirmed Cowden syndrome (four with PTEN mutations). In four of these Cowden patients, the intramucosal lipoma was the index diagnostic lesion. Three (12%) intramucosal lipoma patients had additional clinical features associated with Cowden syndrome, but did not meet the diagnostic criteria. Sporadic-type intramucosal lipomas were identified in 17 patients (68%) without evidence of Cowden syndrome, including three with normal PTEN genetic testing. No distinguishing endoscopic or pathologic polyp features were identified between sporadic and syndromic intramucosal lipomas. These data provide evidence that intramucosal lipomas are important harbingers of Cowden syndrome, making up approximately one-third of this series, the largest in the literature. We also show for the first time that two-thirds of intramucosal lipomas are sporadic. Gastrointestinal pathologists, gastroenterologists, and geneticists should increase their awareness of this subtle but diagnosable lesion strongly associated with Cowden syndrome.

Safety and efficacy of small bowel polypectomy using a balloon-assisted enteroscope in pediatric patients with Peutz-Jeghers syndrome

INTRODUCTION AND AIMS

Peutz-Jeghers syndrome is an autosomal dominant inherited pathology characterized by gastrointestinal hamartomatous polyps, predominantly in the small bowel, and pigmented mucocutaneous lesions. Guidelines suggest polypectomy with a balloon-assisted enteroscope when polyps are larger than 10mm. Complications in adults can be as high as 6.8%, but there is little information on pediatric populations. Our aim was to describe the safety and efficacy of polypectomy in a group of pediatric patients with Peutz-Jeghers syndrome using balloon-assisted enteroscopy.

MATERIALS AND METHODS

A retrospective study was conducted at the Hospital de Especialidades del Centro Médico Nacional Siglo XXI on pediatric patients with Peutz-Jeghers syndrome that required balloon-assisted enteroscopy and polypectomy within the time frame of January 2010 and December 2015. Patients that underwent polypectomy with a push enteroscope were excluded from the study.

RESULTS

A total of 35 polypectomies were performed on 4 patients (female/male: 3/1). The mean age of the patients was 13.7 years (range:11-16). Twelve enteroscopies were carried out, 8 of which were anterograde. A single-balloon enteroscope was used in 7 procedures and a double-balloon enteroscope in 5. The mean size of the polyps was 1.6cm (range: 1-4cm). A major complication (acute pancreatitis) presented in only one case (8.3%). No other major complications associated with the procedures were observed.

CONCLUSION

Balloon-assisted enteroscopy with polypectomy in children is a safe and effective procedure, with complications similar to those reported in adults.

A giant and extensive solitary Peutz-Jeghers-type polyp in the antrum of stomach: Case report

RATIONALE

A solitary Peutz-Jeghers-type polyp is a hamartomatous polyp which without either mucocutaneous pigmentation or a family history of Peutz-Jeghers syndrome (PJS). It can occur in all of the gastrointestinal tract, but it is extremely rare in the stomach.

PATIENT CONCERNS

A 53-year-old man was admitted to the local hospital with left upper abdominal pain lasting 2 weeks. A gastroscopy showed a giant and extensive bulging lesion on the greater curvature and posterior and anterior walls of the gastric antrum, involving three-quarters of the gastric wall. Endoscopic ultrasonography showed a muscularis mucosa lesion.

DIAGNOSES

A solitary Peutz-Jeghers-type polyp in the antrum of stomach.

INTERVENTIONS

The patient underwent an endoscopic submucosal dissection (ESD).

OUTCOMES

The patient recovered quickly, without any complications.

LESSONS

This is the second largest gastric solitary Peutz-Jeghers-polyp reported until now, and the largest gastric solitary Peutz-Jeghers type-polyp treated by endoscope.

Gastrointestinal Polyposis in Cowden Syndrome

GOALS

To further characterize the gastrointestinal manifestations of Cowden syndrome in clinically well-annotated patients to improve the diagnosis of this syndrome.

BACKGROUND

The gastrointestinal manifestations of Cowden Syndrome, an important heritable and multiorgan cancer syndrome, are not well defined. Proper diagnosis is essential for effective cancer surveillance and prevention in these patients.

STUDY

Cowden patients with gastrointestinal polyps were selected for medical record and pathologic slide review.

RESULTS

Of 19 total patients, genetic testing revealed pathogenic PTEN mutations in 12. Pan-colonic (11-patients, 58%) and pan-gastrointestinal (8-patients, 42%) polyp distributions were common. Inflammatory (juvenile) polyps were the most common of the hamartomatous polyp (18 patients, 95%), along with expansive lymphoid follicle polyps (12 patients, 63%), ganglioneuromatous polyps (10 patients, 53%), and intramucosal lipomas (5 patients, 26%). The findings of 2 or more hamartomatous polyp types per patient emerged as a newly described and highly prevalent (79%) feature of Cowden syndrome. Ganglioneuromatous polyps, rare in the general population, and intramucosal lipomas, which may be unique to Cowden syndrome, should both prompt further evaluation. Colonic adenomas and adenocarcinomas were common; 10 patients (53%) had single and 3 (16%) had ≥3 adenomas, whereas 2 (11%) had colonic adenocarcinoma, strengthening the emerging association of colorectal cancer with Cowden syndrome.

CONCLUSIONS

The clinical phenotypes and gastrointestinal manifestations in Cowden syndrome are quite variable but this series adds the following new considerations for this syndromic diagnosis: multiple gastrointestinal hamartomas, especially 2 or more hamartoma types, and any intramucosal lipomas or ganglioneuromas. These features should warrant consideration of Cowden syndrome.

Peutz-Jeghers syndrome with early onset of pre-adolescent gynecomastia: a predigree case report and clinical and molecular genetic analysis

This study reports a case of Peutz-Jeghers syndrome with early onset of gynecomastia, and discusses its clinical characteristics and genetic changes in a family. The clinical characteristics of a child diagnosed with Peutz-Jeghers syndrome in our hospital and his parents were summarized, and related genes were detected in the child and his parents. Furthermore, the therapeutic effect of letrozole was also observed. A five-year-and-three-month-old male patient visited a doctor due to "progressive painless enlargements at bilateral breast for more than two years". The mother of the patient had breast hyperplasia and ovarian cysts, had no hematemesis and hematochezia history, and had two 1-mm pigmented spots on the palm side of the left thumb. The father of the patient revealed no abnormalities. In the child, luteinizing hormone (LH) release peak induced by luteinizing hormone releasing hormone (LHRH) excitation testing was 0.29 U/l, and follicle stimulating hormone (FSH) peak was 0.41 U/l. Karyotype: 46, XY. Gene sequencing revealed a mutation c.658C>T in the serine threonine kinase 11 (STK11) gene in the child and this mother, while the child's father was normal. After one year of oral administration of letrozole, the boy's breasts reduced to stage B2, bone age was 10 years and eight months old, and ΔBA/ΔCA ratio was <1. The patient had early onset of pre-adolescent gynecomastia, had no obvious gastrointestinal symptoms, presented with a few pigmented spots in the skin mucosa, and was diagnosed with Peutz-Jeghers syndrome by genetic testing. Letrozole treatment can effectively control the development of breast and progression of bone age.

Gastrointestinal tract cancers: Genetics, heritability and germ line mutations

Gastrointestinal (GI) tract cancers that arise due to genetic mutations affect a large number of individuals worldwide. Even though many of the GI tract cancers arise sporadically, few of these GI tract cancers harboring a hereditary predisposition are now recognized and well characterized. These include Cowden syndrome, MUTYH-associated polyposis, hereditary pancreatic cancer, Lynch syndrome, Peutz-Jeghers syndrome, familial adenomatous polyposis (FAP), attenuated FAP, serrated polyposis syndrome, and hereditary gastric cancer. Molecular characterization of the genes that are involved in these syndromes was useful in the development of genetic testing for diagnosis and also facilitated understanding of the genetic basis of GI cancers. Current knowledge on the genetics of GI cancers with emphasis on heritability and germ line mutations forms the basis of the present review.

Genetic Testing for Polyposis Syndromes

Colorectal cancer is the third most common cancer diagnosed in the United States with up to 3% of cases being attributable to a hereditary polyposis syndrome. Established diagnostic and/or testing criteria exist for many of the recognized polyposis syndromes and are an important tool in guiding physicians in the identification of individuals who may benefit from referral to a cancer genetics service for hereditary cancer risk assessment. A formal hereditary cancer risk assessment supports fulfillment of obligations for standard of care, as well as minimizes the negative outcomes that may occur in the absence of informed consent for genetic testing. The implications of a diagnosis may extend beyond the individual patient to include at-risk relatives, and as such, much emphasis should be placed on identifying the most informative individual in a family in which to initiate testing. Advances in our understanding of genes associated with hereditary polyposis and the increasing use of testing that relies on next-generation sequencing technologies may lead to the increased likelihood of a genetic diagnosis; however, in those individuals without a genetic diagnosis whose histories remain concerning for hereditary polyposis, knowledge of family history may inform strategies for early detection and prevention.

Colonic Polyps: Diagnosis and Surveillance

Colorectal cancer begins as a polyp that is a benign growth on the mucosal surface of the colon or rectum. Over a period of 5 to 15 years, polyps can degenerate into a cancer, thus invading the colonic wall. Colorectal screening methods are designed to diagnose and remove polyps before they acquire invasive potential and develop into cancer. Screening for colorectal cancer can prevent and reduce mortality. Given the benefits and effectiveness of screening, guidelines exist from multiple organizations. These guidelines risk-stratify patients to determine the age of screening initiation and the interval for repeat screening. Categories of colorectal cancer risk include average risk, increased risk, and high risk based on individual and family medical history. Screening methods vary widely in the ability to diagnose and treat polyps and in the degree of invasiveness or risk of complication to the patient. Colonoscopy is held as the "gold standard" by which all other methods are compared; however, less-invasive modalities including computed tomographic colonography are increasing in popularity.

A rare case of synchronous colocolic intussusception in association with Peutz-Jeghers syndrome

Adult intussusception is rare and is almost always associated with a lead point. Polyposis syndromes are a common cause of adult intussusceptions, with polyps acting as lead points. Peutz–Jeghers syndrome is associated with benign hamartomatous polyps and mucocutaneous pigmentation. Although hamartomatous polyps are not premalignant, there is an increased risk of gastrointestinal and non-gastrointestinal malignancy, most commonly involving the small bowel. Most patients with Peutz–Jeghers syndrome with acute abdomen are diagnosed to have intussusceptions, mostly of the enteroenteric type. Colocolic intussusceptions are rare in Peutz–Jeghers syndrome. To the best of our knowledge, synchronous colocolic intussusception in association with Peutz–Jeghers syndrome has not been previously reported. Here we present a case of malignant jejunal mass and synchronous colocolic intussusceptions in a patient with Peutz–Jeghers syndrome.

[Peutz-Jeghers syndrome manifested as massive melæna at CHU-JRA Madagascar hospital: a case report]

Le syndrome de Peutz-Jeghers (SPJ) est caractérisé par l'association d'une polypose digestive hamartomateuse et d'une lentiginose cutanéo-muqueuse. Les malades sont exposés à des complications mécaniques et hémorragiques. Il s'agit d'un syndrome de prédisposition au cancer. Notre étude a pour objectif de rappeler les diagnostiques d'un syndrome de Peutz-Jeghers, de connaitre les complications ainsi que les progrès thérapeutiques dans la prise en charge. Nous avons rapporté le cas d'un homme de 32 ans présentant un melaena massif. Il a été hospitalisé en service de réanimation chirurgicale pour état de choc hypovolémique difficile à contrôler. Il a nécessité une intervention chirurgicale pour arrêter l'hémorragie. Nous avons trouvé un polype hamartomateux dans le grêle qui a causé le saignement. Le diagnostic d'un Syndrome de Peutz-Jeghers a été posé devant la notion de lentiginose labiale pendant l'enfance. Lors de l'exploration clinique et paraclinique, il ne présente pas encore de cancer. A Madagascar, cette pathologie est encore mal connue. Dans la littérature, le syndrome de Peutz-Jeghers peut être révélé cliniquement ou au stade de complication comme l'hémorragie, l'invagination ou l'occlusion intestinale. Dans notre cas, la maladie est compliquée d'une hémorragie digestive avec état de choc hypovolémique. La polypectomie endoscopique par entéroscopie à double ballonnet permet de diminuer le recours à la chirurgie grêlique d'urgence. Le syndrome de Peutz-Jeghers est une affection rare. Mais il est important aux cliniciens de le connaitre et de penser à sa possibilité en cas d'hémorragie digestive.

Newly Developed Endoscopic Treatment for Small Bowel Polyps: Cold Snare Polypectomy

A 72-year-old man with the history of small bowel carcinoma was diagnosed to have a sessile polyp in the jejunum during a follow-up examination. We performed double-balloon endoscopy and removed the polyp by means of cold snare polypectomy. The follow-up endoscopy showed no residual lesion. Cold snare polypectomy has been established as a safe and effective method for the endoscopic treatment of colonic polyps with a low risk of causing electrocautery burns and perforation. However, this technique has not yet been applied for small bowel lesions. This case report, for the first time, shows the feasibility of performing cold snare polypectomy for small bowel polyps.

Do hereditary syndrome-related gynecologic cancers have any specific features?

Abstract

Hereditary syndromes are responsible for 10 % of gynaecologic cancers, among which hereditary breast-ovarian cancer and hereditary non-polyposis colon cancer syndromes, known as HBOC and Lynch syndromes respectively, present the highest relative risk. The latter predisposes to endometrial cancer and both contribute to ovarian cancer. Cowden syndrome-related endometrial cancer and the increased risk of ovarian, uterine and cervical cancers associated with Peutz-Jeghers syndrome, are also demonstrated, while Li-Fraumeni syndrome patients are prone to develop ovarian and endometrial cancers. Despite these syndromes’ susceptibility to gynaecologic cancers being consensual, it is still not clear whether these tumours have any epidemiologic, clinical, pathologic or imaging specific features that could allow any of the intervening physicians to raise suspicion of a hereditary syndrome in patients without known genetic risk. Moreover, controversy exists regarding both screening and surveillance schemes. Our literature review provides an updated perspective on the evidence-based specific features of tumours related to each of these syndromes as well as on the most accepted screening and surveillance guidelines. In addition, some illustrative cases are presented.

Teaching Points

• HBOC syndrome is mainly associated with ovarian HGSC, which arises in fallopian fimbriae.

• LS-related endometrial tumours show histological diversity and predilection for lower uterine segment.

• LS and CS-related ovarian cancers are mostly of non-serous type, usually endometrioid.

• Ovarian SCTAT and cervical adenoma malignum are strongly associated with PJS.

• Unfortunately, hereditary gynaecologic cancers do not seem to have distinctive imaging features.

The Genetics of Colorectal Cancer

The hereditary colorectal cancer syndromes comprise a heterogeneous group of conditions with varying cancer risks, gastrointestinal polyp types, nonmalignant findings, and inheritance patterns. Although each one is unique in its own right, these syndromes often have overlapping features, making diagnoses difficult in select cases. Obtaining accurate polyp history (histologic type, number, location, and age of onset), cancer history (location, type, and age of onset), and other nonmalignant features is imperative in determining the likely disease diagnosis and thereby the appropriate genetic tests for precise diagnosis in a timely fashion. This process often necessitates collaboration among surgical oncology team members and genetic counselors.

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.

ACG clinical guideline: Genetic testing and management of hereditary gastrointestinal cancer syndromes

This guideline presents recommendations for the management of patients with hereditary gastrointestinal cancer syndromes. The initial assessment is the collection of a family history of cancers and premalignant gastrointestinal conditions and should provide enough information to develop a preliminary determination of the risk of a familial predisposition to cancer. Age at diagnosis and lineage (maternal and/or paternal) should be documented for all diagnoses, especially in first- and second-degree relatives. When indicated, genetic testing for a germline mutation should be done on the most informative candidate(s) identified through the family history evaluation and/or tumor analysis to confirm a diagnosis and allow for predictive testing of at-risk relatives. Genetic testing should be conducted in the context of pre- and post-test genetic counseling to ensure the patient's informed decision making. Patients who meet clinical criteria for a syndrome as well as those with identified pathogenic germline mutations should receive appropriate surveillance measures in order to minimize their overall risk of developing syndrome-specific cancers. This guideline specifically discusses genetic testing and management of Lynch syndrome, familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP), MUTYH-associated polyposis (MAP), Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, serrated (hyperplastic) polyposis syndrome, hereditary pancreatic cancer, and hereditary gastric cancer.

Characterization of the rs2802292 SNP identifies FOXO3A as a modifier locus predicting cancer risk in patients with PJS and PHTS hamartomatous polyposis syndromes

Background

Hamartomatous polyposis syndromes (HPS) are inherited conditions associated with high cancer risk. They include the Peutz-Jeghers and the PTEN hamartoma tumor syndromes, which are caused by mutations in the LKB1 and PTEN genes, respectively. Estimation of cancer risk is crucial in order to optimize surveillance, but no prognostic markers are currently available for these conditions. Our study relies on a ‘signal transduction’ hypothesis based on the crosstalk between LKB1/AMPK and PI3K/PTEN/Akt signaling at the level of the tumor suppressor protein FoxO3A. Interestingly, the FOXO3A rs2802292 G-allele was shown to be associated with longevity, reduced risk of aging-related diseases and increased expression of FoxO3A mRNA.

Methods

We typed rs2802292 in 150 HPS unrelated patients and characterized the expression of FoxO3A by quantitative PCR and immunoblot analysis in human intestinal cell lines.

Results

We found a significantly higher risk for malignancies in females and TT genotype carriers compared to patients having at least one G-allele. Subgroup analysis for each HPS syndrome revealed a G-allele-associated beneficial effect on cancer risk occurring mainly in males. Molecular characterization of human intestinal cell lines showed that the G-allele significantly correlated with increased basal expression of FoxO3A mRNA and protein.

Conclusion

Our results suggest an inverse correlation between the protective allele (G) copy number and cancer risk, and might be useful to optimize surveillance in HPS patients. Further investigations are needed to confirm our hypothesis and to ascertain whether differences in therapeutic response exist across genotypes.

Cowden syndrome complicated by a gastrointestinal stromal tumor

To our knowledge, this is the first report of Cowden syndrome complicated by a gastrointestinal stromal tumor (GIST) of the small bowel. A 42-year-old female patient was found to have an abdominal mass that was diagnosed as the cause of anemia and was surgically extracted. The surgical specimen was found to be a GIST. During the same period, the patient underwent an endoscopic examination of the entire gastrointestinal tract. She was also diagnosed as having Cowden syndrome based on gastrointestinal polyps and skin, thyroid and breast lesions. Cowden syndrome is associated with germline mutations in the tumorsuppressor gene PTEN. PTEN expression may be essential to tumor growth and is a predictive biomarker of the prognosis of both diseases. The present report of such a case is expected to further the analysis of Cowden syndrome.

Management of duodenal-jejunal polyps in children with peutz-jeghers syndrome with single-balloon enteroscopy

OBJECTIVES

Children with Peutz-Jeghers syndrome (PJS) have increased risk of polyp-related complications and emergency laparotomies. The aim of the present study was to assess the efficacy and the safety of endoscopic therapy of small bowel polyps using single-balloon enteroscopy (SBE) in children affected by PJS.

METHODS

Between January 2010 and December 2011, prospectively consecutive PJS children with polyps >15 mm or polyps actively bleeding previously identified using video capsule endoscopy and magnetic resonance imaging underwent therapeutic SBE. The main outcome measurements were the feasibility, the technical performance, and the safety.

RESULTS

A total of 10 children (6 boys; median age 13.7 years, range 5.6-15.6) underwent 23 SBE procedures. Four patients had a history of abdominal surgery. A total of 53 polyps were removed, and 23 of them were >15 mm. The majority of polyps were found in jejunum (85%). The mean insertion depths for antegrade and retrograde approach were 200 ± 80 and 100 ± 50 cm beyond the ileal valve, respectively. The mean procedure time was 75 ± 25 minutes. Mild abdominal pain was reported after 3 procedures. In 1 patient a postpolypectomy perforation occurred.

CONCLUSIONS

In conclusion, SBE is an effective endoscopic tool for treating small bowel polyps in children with PJS, and well-timed polypectomy may optimize patients' care, preventing polyp-related complications and emergency laparotomy. Further larger multicenter studies are warranted to accurately determine the safety of therapeutic SBE in children.

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.

Exome sequencing revealed novel germline mutations in Chinese Peutz-Jeghers syndrome patients

BACKGROUND AND AIMS

Peutz-Jeghers Syndrome (PJS) is an autosomal dominant disorder which predisposes to the development of various cancers. Germline mutation in the serine/threonine kinase 11 gene (STK11) is known as one of the major causes of PJS. However, a notable proportion of PJS samples do not carry any mutation in STK11, suggesting possible genetic heterogeneity in the disease and the existence of other causative variants.

METHODS AND RESULTS

In order to identify other germline variants in the coding regions of the genome that are associated with PJS, we performed exome sequencing in three Chinese individuals with PJS and identified 16 common germline variants (12 protein-coding including STK11, 4 in pre-microRNAs). We further validated protein-coding variants in six PJS individuals (three with wild-type STK11) and predicted the functional impact. As result, we found that 7 coding variants are likely to have functional impacts. Especially, we identified 2 new germline variants which are represented in all six PJS samples and are independent of STK11 mutation.

CONCLUSIONS

Our study provided an exomic view of PJS. The germline variants identified in our analysis may help to resolve the complex genetic background of the disease and thus lead to the discovery of novel causative variants of PJS.

Toxicogenomics and cancer susceptibility: advances with next-generation sequencing

The aim of this review is to comprehensively summarize the recent achievements in the field of toxicogenomics and cancer research regarding genetic-environmental interactions in carcinogenesis and detection of genetic aberrations in cancer genomes by next-generation sequencing technology. Cancer is primarily a genetic disease in which genetic factors and environmental stimuli interact to cause genetic and epigenetic aberrations in human cells. Mutations in the germline act as either high-penetrance alleles that strongly increase the risk of cancer development, or as low-penetrance alleles that mildly change an individual's susceptibility to cancer. Somatic mutations, resulting from either DNA damage induced by exposure to environmental mutagens or from spontaneous errors in DNA replication or repair are involved in the development or progression of the cancer. Induced or spontaneous changes in the epigenome may also drive carcinogenesis. Advances in next-generation sequencing technology provide us opportunities to accurately, economically, and rapidly identify genetic variants, somatic mutations, gene expression profiles, and epigenetic alterations with single-base resolution. Whole genome sequencing, whole exome sequencing, and RNA sequencing of paired cancer and adjacent normal tissue present a comprehensive picture of the cancer genome. These new findings should benefit public health by providing insights in understanding cancer biology, and in improving cancer diagnosis and therapy.

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.