Genetics of the hamartomatous polyposis syndromes: a molecular review

Human intestinal organoids from Cronkhite-Canada syndrome patients reveal link between serotonin and proliferation

Cronkhite-Canada Syndrome (CCS) is a rare, noninherited polyposis syndrome affecting 1 in every million individuals. Despite over 50 years of CCS cases, the etiopathogenesis and optimal treatment for CCS remains unknown due to the rarity of the disease and lack of model systems. To better understand the etiology of CCS, we generated human intestinal organoids (HIOs) from intestinal stem cells isolated from 2 patients. We discovered that CCS HIOs are highly proliferative and have increased numbers of enteroendocrine cells producing serotonin (also known as 5-hydroxytryptamine or 5HT). These features were also confirmed in patient tissue biopsies. Recombinant 5HT increased proliferation of non-CCS donor HIOs and inhibition of 5HT production in the CCS HIOs resulted in decreased proliferation, suggesting a link between local epithelial 5HT production and control of epithelial stem cell proliferation. This link was confirmed in genetically engineered HIOs with an increased number of enteroendocrine cells. This work provides a new mechanism to explain the pathogenesis of CCS and illustrates the important contribution of HIO cultures to understanding disease etiology and in the identification of novel therapies. Our work demonstrates the principle of using organoids for personalized medicine and sheds light on how intestinal hormones can play a role in intestinal epithelial proliferation.

Colonic Hamartomatous Ganglioneuromatosis in a 4 Mo Old Puppy

A 4 mo old male goldendoodle puppy was evaluated for chronic hematochezia with a history of recurrent rectal prolapse and tenesmus. A colo-colonic intussusception was diagnosed via abdominal imaging. Surgery was elected to reduce the intussusception, wherein a colonic mass was discovered. Colonic resection and anastomosis was performed, and the tissue were submitted for histopathological examination. The puppy was diagnosed with colonic hamartomatous ganglioneuromatosis based on the presence of markedly hyperplastic submucosal and myenteric plexi with infiltration and expansion of the mucosa and submucosa by Schwann cells and neuronal cell bodies. Ganglioneuromatosis is a rarely reported entity in the veterinary literature, and limited clinical follow up data is available for described cases. In humans, ganglioneuromatosis is associated with a PTEN genetic mutation, which confers increased susceptibility to the development of neoplasia of endocrine organs. Approximately 1 yr after the operation, this puppy appeared clinically normal with no abnormalities on repeated imaging. This case report describes the clinical presentation, surgical treatment, and histologic features of colonic hamartomatous ganglioneuromatosis with 1 yr postoperative clinical follow up data in a dog. Although uncommon, ganglioneuromatosis should be considered as a differential diagnosis list as a cause of gastrointestinal masses in puppies and young dogs.

Adenomatous Polyposis Phenotype in BMPR1A and SMAD4 Variant Carriers

INTRODUCTION

Variants in SMAD4 or BMPR1A cause juvenile polyposis syndrome, a rare autosomal dominant condition characterized by multiple gastrointestinal hamartomatous polyps. A phenotype of attenuated adenomatous polyposis without hamartomatous polyps is rare.

METHODS

We describe a retrospective cohort of individuals with SMAD4 or BMPR1A heterozygous germline variants, having ≥10 cumulative colorectal adenomas and/or colorectal cancer without hamartomatous polyps. All individuals had multigene panel and duplication/deletion analysis to exclude other genetic syndromes.

RESULTS

The study cohort included 8 individuals. The pathogenic potential of the variants was analyzed. Variants detected included 4 missense variants, 1 nonsense variant, 1 splice site variant, and 2 genomic deletions. Features of pathogenicity were present in most variants, and cosegregation of the variant with polyposis or colorectal cancer was obtained in 7 of the 8 families. Three of 8 individuals had colorectal cancer (age less than 50 years) in addition to the polyposis phenotype. Two individuals had extraintestinal neoplasms (pancreas and ampulla of Vater).

DISCUSSION

The clinical phenotype of SMAD4 and BMPR1A variants may infrequently extend beyond the classical juvenile polyposis syndrome phenotype. Applying multigene panel analysis of hereditary cancer-related genes in individuals with unexplained polyposis can provide syndrome-based clinical surveillance for carriers and their family members.

Gardner syndrome: A case report

BACKGROUND

Gardner syndrome is a special subtype of familial adenomatous polyposis (FAP) and it is an autosomal dominant genetic disease mainly characterized by multiple gastrointestinal polyps, soft tissue tumors, and osteomas. It is a rare disease, and there are few relevant reports about it. However, the malignant transformation rate of Gardner syndrome is high. Therefore, understanding of its main clinical features, and early examination and timely discovery are of great significance for its treatment.

CASE SUMMARY

We report the case of a 39-year-old man diagnosed with Gardner syndrome who presented with anemia and melena for more than 4 mo, along with nausea and vomiting for more than 20 d. Gastrointestinal endoscopy revealed multiple polyps in the gastrointestinal tract and polyp biopsy pathology confirmed the diagnosis. Endoscopic treatment was performed, and the patient had no postoperative discomfort. Finally, his condition improved.

CONCLUSION

The clinical manifestations of Gardner syndrome are complex. The combination of clinical manifestations with relevant imaging and pathological examination results can help achieve early diagnosis and early treatment. Early treatment is usually associated with a good prognosis.

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.

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.

Laparoscopic-assisted disinvagination and polypectomy for multiple intussusceptions induced by small intestinal polyps in patients with Peutz-Jeghers syndrome: a case report

Background

Peutz–Jeghers syndrome (PJS) is a very rare autosomal dominant genetic disorder characterized by hamartomatous polyps in the gastrointestinal tract and hyperpigmentation of the lips, hands, and feet. The hamartomatous polyps in the small intestine often cause intussusception and bleeding.

Case presentation

A 62-year-old male was hospitalized for treatment of deep vein thrombosis and pulmonary embolism. In the small intestine, computed tomography showed three small polyps with intussusceptions. Since the patient had gastrointestinal polyposis and pigmentation of his lips, fingers, and toes, he was diagnosed with PJS. After an inferior vena cava filter was placed, he underwent laparoscopic-assisted surgery. The polyps causing intussusception were resected as far as possible without intestinal resection, since they had caused progressive anemia and might cause intestinal obstruction in the future. The patient was discharged from the hospital on postoperative day 9 without complications.

Conclusions

Laparoscopic-assisted disinvagination and polypectomy is a useful, minimally invasive treatment for multiple intussusceptions caused by small intestinal polyps in patients with PJS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02133-5.

Register and clinical follow-up of patients with Peutz-Jeghers syndrome in Valencia

INTRODUCTION AND OBJECTIVES

Peutz-Jeghers syndrome is a rare autosomal dominant inherited disease caused by a germline mutation of the STK11/LKB1 gene, located on chromosome 19p13.3. It is characterized by mucocutaneous hyperpigmentation, hamartomatous polyposis, and predisposition to cancer. The aim of the present study was to identify and register patients with Peutz-Jeghers syndrome, describe the disease, and estimate its prevalence in Valencia (Spain).

MATERIALS AND METHODS

A print-out of the clinical histories from 10 hospitals was obtained utilizing the ICD-9 code 759.6 from the Minimum Basic Data Set of Hospital Admissions of the Spanish Ministry of Health and Consumer Affairs.

RESULTS

From a total of 405 clinical histories found, 15 (9 males and 6 females) fit the diagnostic criteria of Peutz-Jeghers syndrome. Mean age at diagnosis was 13.8 years and mean age at death was 54.2 years. Four males died, all from cancer. The estimated disease prevalence was 0.4/100,000 inhabitants. All the patients presented with anemia and polyps in the small bowel (80% in the duodenum, 66.7% in the ileum, and 40% in the jejunum), 93.3% underwent urgent surgical intervention and presented with intestinal invagination, and 40% of the patients developed cancer at a mean age of 48.5 years.

CONCLUSION

The present study is the first register of patients with Peutz-Jeghers syndrome in Valencia, Spain. The ICD-9 code is nonspecific for rare diseases. The duodenum was the most frequent location for polyps and the majority of cases presented with intestinal invagination, bowel obstruction, and urgent surgical intervention. A large percentage of patients presented with cancer. It would be of interest to review and evaluate the existing surveillance protocols in the Valencian Community.

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.

Cronkhite-Canada Syndrome: Sustained Clinical Response with Anti-TNF Therapy

Cronkhite-Canada syndrome (CCS) is a rare, nonfamilial syndrome that occurs in the sixth to seventh decades of life. It is characterized by acquired gastrointestinal polyposis with an associated ectodermal triad, including alopecia, onchodystrophy, and hyperpigmentation. CCS is characteristically a progressive disease, with a high mortality rate despite medical interventions. Disease complications are typically secondary to severe malnutrition, malignancy, GI bleeding, and infection. CCS is believed secondary to immune dysregulation; however, the underlying etiology remains to be determined. Treatment for CCS is largely anecdotal, and randomized controlled therapeutic trials are lacking due to the rarity of the disease. Aggressive nutritional support in conjunction with immunosuppression has been used previously with inconsistent results. In this report, we describe the presentation and diagnosis of a case of CCS and report encouraging treatment response with anti-TNF therapy.

Germline variants in Hamartomatous Polyposis Syndrome-associated genes from patients with one or few hamartomatous polyps

OBJECTIVE

A subgroup of patients with hamartomatous polyps in the GI tract has a hereditary Hamartomatous Polyposis Syndrome with an increased risk of cancer. The distinction between patients with one or few polyps and patients with a syndrome can be difficult. A pathogenic germline mutation can be detected in a majority of HPS patients. This study investigates whether patients with one or few hamartomatous polyps could have a syndrome based on genetic screening of relevant genes.

METHODS

We designed a gene panel including 26 hamartomatous polyposis-associated genes. Using targeted Next Generation Sequencing, DNA samples from 77 patients with 84 hamartomatous polyps were sequenced. The detected germline variants were classified into pathogenicity classes.

RESULTS

We detected several germline variants, among them three in ENG, two in BMPR1A, one in PTEN, and one in SMAD4. Although some of the detected variants have been reported previously none could be definitely pathogenic or likely pathogenic.

CONCLUSIONS

Our study points towards that genetic testing for the Hamartomatous Polyposis Syndromes in patients with one or few polyps does not improve diagnostics, however we illustrate that the clinical significance of genetic variants can be difficult to interpret. A family history of polyps, cancer, or extraintestinal findings or a minimum of 3-5 polyps seems to be relevant information to include before genetic testing.

Clinical and molecular features of young-onset colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer related mortality worldwide. Although young-onset CRC raises the possibility of a hereditary component, hereditary CRC syndromes only explain a minority of young-onset CRC cases. There is evidence to suggest that young-onset CRC have a different molecular profile than late-onset CRC. While the pathogenesis of young-onset CRC is well characterized in individuals with an inherited CRC syndrome, knowledge regarding the molecular features of sporadic young-onset CRC is limited. Understanding the molecular mechanisms of young-onset CRC can help us tailor specific screening and management strategies. While the incidence of late-onset CRC has been decreasing, mainly attributed to an increase in CRC screening, the incidence of young-onset CRC is increasing. Differences in the molecular biology of these tumors and low suspicion of CRC in young symptomatic individuals, may be possible explanations. Currently there is no evidence that supports that screening of average risk individuals less than 50 years of age will translate into early detection or increased survival. However, increasing understanding of the underlying molecular mechanisms of young-onset CRC could help us tailor specific screening and management strategies. The purpose of this review is to evaluate the current knowledge about young-onset CRC, its clinicopathologic features, and the newly recognized molecular alterations involved in tumor progression.

Preexisting adrenal masses in patients with adrenocortical carcinoma: clinical and radiological factors contributing to delayed diagnosis

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy that is usually large (>5 cm) at time of diagnosis. Delayed diagnosis significantly worsens survival. We describe adrenal gland morphology prior to ACC diagnosis and discern potential causes of delayed diagnosis. ACC patients seen at The University of Texas MD Anderson Cancer Center between 1998 and 2014 who had cross-sectional body imaging ≥3 months prior to their diagnosis. We conducted a detailed review of clinical and radiological features in these patients prior to ACC diagnosis. Of 439 patients with ACC, 25 had imaging preceding ACC diagnosis (5 with normal adrenal glands and 20 with preexisting masses). On the first available images, the median mass size was 2.8 cm (range 0-9) with median precontrast density of 36 Hounsfield units (range 17-43) and became 9 cm (range 1-18) at the time of ACC diagnosis. The median interval between first available image and ACC diagnosis was 20 months (range 3-89). In the 5 patients whose initial images showed normal adrenal glands, the time between the last normal scan and ACC diagnosis ranged from 5 to 36 months. The most common reason for delayed ACC diagnosis was the presumed benign status of the preexisting mass (n = 13, 65 %). Radiologically suspicious adrenal masses can precede ACC diagnosis and have variable growth patterns. ACC can also develop de novo within a few months in a radiologically documented normal adrenal gland. The presumed benignancy of preexisting masses based on size is the main reason for delayed ACC diagnosis.

Hereditary Colorectal Cancer in China: Current Status and Progress

<b><i>Background:</i></b> Hereditary colorectal cancer (CRC) accounts for about 5% of the total incidence of CRC. During the last decades, there have been great advances in the research of hereditary CRC in China. <b><i>Summary:</i></b> This review mainly focuses on advances of the genetic basis, clinicopathological features, diagnosis, chemoprevention and treatment of hereditary CRC in China. <b><i>Key Message:</i></b> Hereditary CRC has a higher risk to initiate the progression towards neoplasia than sporadic CRC. It can be diagnosed by clinical manifestation or the relevant genetic testing so as to guide the clinical treatment to improve the survival rate and survival quality of patients. <b><i>Practical Implications:</i></b> Hereditary CRC includes hereditary nonpolyposis CRC (Lynch syndrome), familial adenomatous polyposis and other rare types such as Peutz-Jeghers syndrome and familial juvenile polyposis. Based on the clinical manifestations and family history, highly suspected cases can be screened for in the general population and the diagnosis ruled out by genetic analysis. Then, chemoprevention, endoscopic intervention or surgery can be selected properly to improve patients' survival and quality of life.

Cronkhite–Canada syndrome six decades on: the many faces of an enigmatic disease

Cronkhite–Canada syndrome is a rare gastro-enterocolopathy of uncertain aetiology first described almost 60 years ago. It is characterised by diffuse gastrointestinal polyposis sparing only the oesophagus, ectodermal abnormalities and an unpredictable but often fatal clinical course. The disease may demonstrate extremely diverse clinical and endoscopic features, which often leads to a delay in diagnosis. A high index of suspicion and recognition of the characteristic histological findings frequently facilitate a correct diagnosis, but the distribution of the gastrointestinal pathology and its microscopic features may be atypical. The pathologist thus requires a thorough knowledge of both the typical and many atypical faces of this disease, for which various documented therapies often still prove ineffective. Close correlation with clinical findings, including any pertinent ectodermal abnormalities, and careful examination of biopsies derived from polypoid and endoscopically spared mucosa will ensure a timely and correct diagnosis in patients with this enigmatic syndrome.

Oral neurovascular hamartoma: an extraordinary verdict in the oral cavity

The presence of a neurovascular hamartoma within the oral cavity is truly a rare entity. Scarcely reported in the literature, these hamartomas are smooth, pinkish masses and are painless, and therefore difficult to diagnose. They are benign in nature and apply pressure to their surroundings. The histological diagnosis remains the gold standard as it comprises of neural tissue and vascular components. Treatment is surgical excision with adequate margins. Recurrence is reported in cases of incomplete resection.

Juvenile-like (inflammatory/hyperplastic) mucosal polyps of the gastrointestinal tract in neurofibromatosis type 1

AIMS

Diffuse neurofibromatosis/ganglioneuromatosis, solitary/plexiform neurofibroma, periampullary carcinoids and gastrointestinal stromal tumour (GIST) are the main gastrointestinal manifestations of neurofibromatosis type 1 (NF-1, von Recklinghausen disease). Inflammatory (juvenile-like) polyps have not been recognised to date as specific gastrointestinal (GI) manifestations of NF-1.

METHODS AND RESULTS

We describe four males aged 23-65 years with NF-1 and inflammatory (juvenile-like) gastrointestinal polyps, and review the literature for similar cases. Two patients had single polyps (sigmoid colon and antrum, respectively), one had two polyps (left colon), and one had three polyps (distal oesophagus and colon). Histological appearances were variable, ranging from juvenile-like to granulation tissue-rich, predominantly inflammatory and hyperplastic. Three lesions showed obliterative vasculopathic changes. None had neurofibromatous or ganglioneuromatous polyps. A review of the literature disclosed 11 similar cases. Most patients presented with severe gastrointestinal symptoms and/or anaemia.

CONCLUSIONS

NF-1-associated inflammatory polyps probably represent specific GI manifestations of this disorder, and should be considered, particularly in patients with GI symptoms. They should be distinguished from inflammatory fibroid polyps and from juvenile-like changes associated with ganglioneuroma/ganglioneuromatosis and neurofibroma/neurofibromatosis. Their aetiology remains obscure, but different mechanisms, including NF-1 inactivation, NF-1-associated vasculopathy, and localised mucosal prolapse/damage caused by motility disorders, might be involved.

Polyposis Syndromes: Role of the Pathologist

This article reviews the major gastrointestinal polyposis syndromes, with an emphasis on the molecular, clinical, and histopathological features of each. Salient features helpful in making or suggesting the diagnosis of these syndromes are discussed, as is the use of ancillary techniques, such as immunohistochemistry and molecular diagnostic studies in diagnosis confirmation and family screening.

Autosomal Dominant Inherited Cowden's Disease in a Family

Cowden's disease, also known as a kind of phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome, is an uncommon autosomal dominant inherited complex disorder with various hamartomatous growths of multiple organs involving all three germ cell layers. It usually manifests with polyps throughout the gastrointestinal tract, ranging anywhere from 30% to 85%, and more common extra intestinal findings. Mucocutaneous lesions like facial trichilemmomas, acral keratoses, papillomatous papules and macrocephaly, and malignancies including breast, thyroid and endometrial carcinoma are the hallmark of the disease. Here we report on familial Cowden's diseases case of a 52-year-old male proband with mucocutaneous lesions and mutation on the PTEN gene obtained by extrapolating from gastrointestinal polyposis as a starter and his daughter who developed thyroid cancer.

Jejunal intussusception and polyps with different types of malignant transformation in Peutz-Jeghers syndrome: Report of a case

Intussusception and malignant polyps are complications of Peutz-Jeghers syndrome. Very few cases of intussusception combined with polyps with different types of malignant transformation in Peutz-Jeghers syndrome have been reported to date. In the present study, we describe a case of Peutz-Jeghers syndrome with jejunal intussusception and malignant hamartoma in the jejunum and descending colon, combined with mucinous adenocarcinoma in the sigmoid colon.

Surveillance of patients affected by Peutz-Jeghers syndrome: diagnostic value of MR enterography in prone and supine position

INTRODUCTION

Peutz-Jeghers syndrome (PJS) is a familial polyposis syndrome characterized by multiple hamartomatous polyps throughout the gastrointestinal tract. The aim of our study was to retrospectively determine the diagnostic value of MR enterography (MRE), performed in supine and prone position, in the detection of small bowel polyps in PJ patients.

MATERIALS AND METHODS

We retrospectively reviewed MRE examinations of 8 PJS patients who underwent MRE, pushed-double-ballon enteroscopy, laparoscopic endoscopy or surgery, within 3 months. Polietilenglicole was orally administered before the examination. True FISP and HASTE sequences were acquired in supine and prone position; 3D VIBE Gd-enhanced sequences in prone position only.

RESULTS

Concordance between MRE and endoscopy was 72.6% for polyps <15 mm, 93% for polyps >15 mm. In supine and prone position concordance with endoscopy for polyps <15 mm was 63% and 66.8%, respectively. In the detection of smaller polyps the difference between supine position only and supine plus prone position was statistically significant (P < 0.027).

DISCUSSION

MRE performed by combining prone and supine position was accurate in the detection of PJS polyps, with 93% concordance with enteroscopy for larger and more risky polyps. MRE offers a promising and non invasive alternative to capsule endoscopy, suggesting the possibility of an effective yearly surveillance in PJ patients.

Advances in the prevention, diagnosis and treatment of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disease caused by inactivating germline mutations of the LKB1/STK11 gene and characterized by mucocutaneous pigmentation, multiple gastrointestinal hamartomatous polyps and family history. Life-threatening complications include intestinal obstruction and an increased risk for developing gastrointestinal malignancies and extraintestinal cancers. Surgery and endoscopic therapy are still main ways to manage gastrointestinal polyposis in PJS patients, and double-balloon enteroscopy has important clinical significance in the diagnosis and treatment of this disease. With the development of translational medicine, molecular targeted therapy (e.g., selective COX-2 inhibitors) brings a new approach to preventive treatment of gastrointestinal polyposis in PJS patients. Traditional Chinese medicine provides an alternative choice. In this paper, we review the recent advances in the prevention, diagnosis and treatment of PJS.

[Non-serrated precursor lesions of colorectal tumours]

Non-serrated precursor lesions of colorectal tumours include conventional adenomas (tubular, tubulovillous and villous), inflammatory bowel disease-associated dysplasia (intraepithelial neoplasia), and hamartoma-associated dysplasia. This short review summarizes the current literature on the adenoma-carcinoma sequence, focusing on colonic stem cells and functional crypt organization, patterns of stem cell division, niche succession and clonal conversion in the formation of a monocryptal adenoma. The process of clonal interaction between neighboring crypts as well as the development of large monoclonal adenomas from small polyclonal precursor lesions is discussed in detail. Finally, the molecular pathogenesis as well as the clinical significance of inflammatory bowel disease- and hamartoma-associated carcinogenesis is addressed.

MOLECULAR BASIS OF HEREDITARY COLORECTAL CANCER

Advances in molecular biology have defined the molecular basis for colorectal cancer (CRC). Though only a fraction of CRC has been determined to have a hereditary component, the discovery of genetic alterations in these clinical syndromes has permitted definition of similar discoveries in sporadic CRC. Here we will delineate the molecular basis for the most common of these defined syndromes, including familial adenomatous polyposis, hereditary non-polyposis colon cancer, MUTYH associated polyposis, Juvenile polyposis, Peutz-Jeghers syndrome, and Cowden's syndrome. The newest paradigm with implications for the pathogenesis of sporadic CRC is called the cancer stem cell hypothesis. As this paradigm also implicates aberrations in molecular pathways, a brief discussion of this hypothesis is included.

Colorectal Hamartomatous Polyposis and Ganglioneuromatosis in a Dog

A 5-month-old female Great Dane puppy was treated for hematochezia, tenesmus, and rectal prolapse by resection of a 10-cm-long segment of colon and rectum. Grossly, the colorectal segment had diffuse mucosal and submucosal thickening with multiple polypoid nodules. The histologic diagnosis was colorectal hamartomatous polyps with ganglioneuromatosis. Duplication of PTEN was detected by quantitative multiplex polymerase chain reaction testing. The presence of 2 hamartomatous colorectal lesions with PTEN mutation is similar to human Cowden syndrome.

Single nucleotide polymorphisms in the Wnt and BMP pathways and colorectal cancer risk in a Spanish cohort

Background

Colorectal cancer (CRC) is considered a complex disease, and thus the majority of the genetic susceptibility is thought to lie in the form of low-penetrance variants following a polygenic model of inheritance. Candidate-gene studies have so far been one of the basic approaches taken to identify these susceptibility variants. The consistent involvement of some signaling routes in carcinogenesis provided support for pathway-based studies as a natural strategy to select genes that could potentially harbour new susceptibility loci.

Methodology/Principal Findings

We selected two main carcinogenesis-related pathways: Wnt and BMP, in order to screen the implicated genes for new risk variants. We then conducted a case-control association study in 933 CRC cases and 969 controls based on coding and regulatory SNPs. We also included rs4444235 and rs9929218, which did not fulfill our selection criteria but belonged to two genes in the BMP pathway and had consistently been linked to CRC in previous studies. Neither allelic, nor genotypic or haplotypic analyses showed any signs of association between the 37 screened variants and CRC risk. Adjustments for sex and age, and stratified analysis between sporadic and control groups did not yield any positive results either.

Conclusions/Significance

Despite the relevance of both pathways in the pathogenesis of the disease, and the fact that this is indeed the first study that considers these pathways as a candidate-gene selection approach, our study does not present any evidence of the presence of low-penetrance variants for the selected markers in any of the considered genes in our cohort.

Klinik und Genetik des familiären Darmkrebses

Eine familiäre Häufung von Dickdarmkrebs (CRC) und ein früher Erkrankungsbeginn sind Hinweise auf erbliche Tumorsyndrome, die für etwa 3–5% aller CRC verantwortlich sind. Bei diesen monogenen Dispositionen wird der erbliche Dickdarmkrebs ohne Polyposis (HNPCC/Lynch-Syndrom) von der Gruppe der gastrointestinalen Polyposis-Syndrome unterschieden. Bei vielen hereditären Formen besteht ein z. T. charakteristisches Spektrum extrakolonischer Tumoren. Die frühe Erkennung und korrekte Einordnung ist wichtig, da effektive Methoden der Vorsorge und Therapie für Betroffene und Risikopersonen bestehen.

Die Initialdiagnostik umfasst das endoskopische Bild und den histologischen Befund, ergänzt um extraintestinale Manifestationen und die Familienanamnese. Die molekulargenetische Abklärung erfolgt nach weitgehend etablierten und standardisierten Algorithmen. Differenzialdiagnostische Probleme bereiten insbesondere Patienten mit wenigen kolorektalen Adenomen sowie phänotypische Überlappungen bei hamartomatösen Polyposis-Syndromen. Für HNPCC und häufige Polyposis-Syndrome existieren etablierte risikoadaptierte Früherkennungsprogramme.

Der außerhalb der etablierten Tumorsyndrome beobachteten familiären Häufung des – oft spätmanifesten – CRC und dem Auftreten weniger Adenome liegt vermutlich eine multifaktorielle Ätiologie zugrunde. Die Aufklärung der genetischen Faktoren und das Verständnis der beteiligten Signalwege steht hier noch am Anfang, macht aber durch die rasanten methodischen Entwicklungen (z. B. genomweite Assoziationsstudien, CNV-Analysen) rasche Fortschritte.

Hedgehog signaling in gastric physiology and cancer

The Hedgehog family of ligands was originally identified in mutagenesis screens of Drosophila embryos. Hedgehog signaling in multiple tissues is important during embryonic development. A common theme regarding Hedgehog expression in adult tissues is that tissue injury reactivates the developmental pattern of expression. In most instances, this appears to be important to initiate tissue repair. In the gastrointestinal (GI) tract, where epithelial cells are constantly replenished from progenitor populations, Hedgehog signaling also appears to be essential for regeneration. By contrast, reactivated Hedgehog signaling in adult tissues does not automatically predispose the tissue to transformation, but instead requires sustained tissue injury in the form of chronic inflammation. In this chapter, we review what is known about Hedgehog ligands and signaling during development of relevant organs, and discuss how the patterns of Hedgehog regulation are recapitulated in the GI tract during embryogenesis, adult homeostasis, and neoplastic transformation.

Peutz-Jeghers syndrome: Diagnostic and therapeutic approach

Peutz-Jeghers syndrome (PJS) is an inherited, autosomal dominant disorder distinguished by hamartomatous polyps in the gastrointestinal tract and pigmented mucocutaneous lesions. Prevalence of PJS is estimated from 1 in 8300 to 1 in 280 000 individuals. PJS predisposes sufferers to various malignancies (gastrointestinal, pancreatic, lung, breast, uterine, ovarian and testicular tumors). Bleeding, obstruction and intussusception are common complications in patients with PJS. Double balloon enteroscopy (DBE) allows examination and treatment of the small bowel. Polypectomy using DBE may obviate the need for repeated urgent operations and small bowel resection that leads to short bowel syndrome. Prophylaxis and polypectomy of the entire small bowel is the gold standard in PJS patients. Intraoperative enteroscopy (IOE) was the only possibility for endoscopic treatment of patients with PJS before the DBE era. Both DBE and IOE facilitate exploration and treatment of the small intestine. DBE is less invasive and more convenient for the patient. Both procedures are generally safe and useful. An overall recommendation for PJS patients includes not only gastrointestinal multiple polyp resolution, but also regular lifelong cancer screening (colonoscopy, upper endoscopy, computed tomography, magnetic resonance imaging or ultrasound of the pancreas, chest X-ray, mammography and pelvic examination with ultrasound in women, and testicular examination in men). Although the incidence of PJS is low, it is important for clinicians to recognize these disorders to prevent morbidity and mortality in these patients, and to perform presymptomatic testing in the first-degree relatives of PJS patients.

Advances in research on hereditary colorectal neoplasms

Colorectal cancer is one of the most common digestive malignant tumors in China. Its incidence and mortality rates rank top among all malignant tumors. Previous studies show that nearly one-third of colorectal cancers are associated with hereditary colorectal tumors. Hereditary colorectal tumors are mainly divided into two categories: hereditary nonpolyposis colorectal cancer and hereditary colorectal polyposis. In this article, we will review the recent advances in research on hereditary colorectal neoplasms.