Characteristics of small bowel carcinoma in hereditary nonpolyposis colorectal carcinoma. International Collaborative Group on HNPCC

Molecular Landscape of Small Bowel Adenocarcinoma

Small bowel adenocarcinoma (SBA) is a rare malignancy, with lower incidence, later stage at diagnosis, and poor overall prognosis compared to other cancers of the gastrointestinal tract. Owing to the rarity of the disease along with the paucity of high-quality tissue samples and preclinical models, little is known about the molecular alterations characteristic of SBA. This is reflected by the fact that the clinical management of SBA is primarily extrapolated from colorectal cancer (CRC). Recent advances in genomic profiling have highlighted key differences between these tumors, establishing SBA as a molecularly unique intestinal cancer. Moreover, comprehensive molecular analysis has identified a relatively high incidence of potentially targetable genomic alterations in SBA, predictive of response to targeted and immunotherapies. Further advances in our knowledge of the mutational and transcriptomic landscape of SBA, guided by an increased understanding of the molecular drivers of SBA, will provide opportunities to develop novel diagnostic tools and personalized therapeutic strategies.

Clinically actionable findings on surveillance EGD in asymptomatic patients with Lynch syndrome

BACKGROUND AND AIMS

Lynch syndrome (LS) predisposes patients to multiple cancers including of the gastric and small bowel. Data supporting EGD surveillance in LS are limited. Our aim is to describe upper GI (UGI) findings in asymptomatic LS patients undergoing EGD surveillance within a hereditary colorectal cancer registry.

METHODS

Asymptomatic patients with LS who underwent ≥1 surveillance EGD were included. Demographics, genotype, and EGD findings were reviewed. The frequency of clinically actionable findings including neoplasia (cancer, adenomas), Barrett's esophagus (BE), Helicobacter pylori, and hyperplastic polyps >5 mm were assessed.

RESULTS

Three hundred twenty-three patients underwent 717 EGDs starting at a median age of 49.5 years. On average, each patient had 2 EGDs with an interval of 2.3 years between examinations. Clinically actionable findings were identified in 57 patients (17.6%). On baseline EGD 27.7% of findings were identified, with the remainder on surveillance EGD over an average of 3.5 years. Five asymptomatic patients (1.5%) had an UGI cancer detected during surveillance, all at early stage, including 1 patient each with BE-related esophageal adenocarcinoma, gastric neuroendocrine tumor, and gastric adenocarcinoma and 2 patients with duodenal adenocarcinoma. Two cancers were found on baseline EGD and 3 on follow-up EGD.

CONCLUSIONS

Clinically actionable findings were found in approximately 1 in 6 asymptomatic patients with LS undergoing EGD surveillance. Five patients (1.5%) were diagnosed with cancer, all detected at an early stage. These data suggest that both baseline and follow-up EGD surveillance are effective in detecting early-stage UGI cancers in asymptomatic patients with LS.

Using Immunohistochemistry to Expand the Spectrum of Lynch Syndrome-Related Tumors

The most common genetic and molecular process leading to sporadic colorectal cancer is chromosomal instability. By contrast, mismatch repair deficiency, which results in high levels of microsatellite instability or lack of mismatch repair (MMR) protein expression on immunohistochemistry (IHC), is the predominant cancer pathway in patients with Lynch syndrome (LS). Importantly, patients with LS may still develop sporadic tumors through chromosomal instability. Testing tumors with IHC staining helps expand the spectrum of LS-related tumors. In this series, we describe 4 cancers in patients with LS that are not typical of the syndrome. Lack of MMR protein expression on IHC staining confirmed that 2 cancers are related to LS, expanding the spectrum of LS-related tumors, and the presence of MMR protein expression on IHC in the other 2 cases confirmed that they were sporadic and not related to mismatch repair deficiency and, thus, not related to LS.

Endoscopy to Diagnose and Prevent Digestive Cancers in Lynch Syndrome

Lynch syndrome patients could benefit from various recommendations to prevent digestive cancers. In this review, we summarize the criteria to identify Lynch syndrome in patients with digestive cancers. We detail endoscopic screening procedures in patients with Lynch syndrome for gastric, small bowel, pancreatic, and colorectal cancers. We review the precise modalities of endoscopic follow-up, particularly the discrepancies that exist between the guidelines of the various scientific societies. We discuss the treatment of colorectal cancers in Lynch syndrome cases and patient adherence to endoscopic follow-up programs.

When to Consider Lynch Syndrome in Non-Colon and Non-Endometrial Malignancies

Lynch syndrome (LS) is a common genetic syndrome characterized by pathogenic mutations of DNA mismatch repair genes resulting in a hereditary predisposition to cancer. While typically associated with colonic and endometrial cancer, LS additionally influences the development of many other malignancies. The Amsterdam II and Revised Bethesda Guidelines are the established clinical criteria for diagnosing LS. These guidelines are based on the most general characteristics of LS and do not address specific characteristics of the less commonly LS-associated malignancies. For individuals that present initially with a non-colon and non-endometrial malignancy, recommendations and guidelines on when to consider screening for LS are limited. Therefore, it is essential that clinicians are familiar with distinct LS-associated patient- and tumor-specific characteristics, especially of the less common LS-associated cancers, so that LS's diagnosis is not missed. In this review article, we focus on extra-colonic and extra-endometrial LS-associated cancers, paying particular attention to any established or currently investigated cancer features that help raise suspicion for LS and potentially lead to its earlier diagnosis. This review will also discuss current guidelines specific to each LS-associated malignancy.

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.

Characterization and Clinical Outcomes of DNA Mismatch Repair-deficient Small Bowel Adenocarcinoma

PURPOSE

The prevalence and clinical characteristics of small bowel adenocarcinomas (SBA) in the setting of Lynch syndrome have not been well studied. We characterized SBA according to DNA mismatch repair and/or microsatellite instability (MMR/MSI) and germline mutation status and compared clinical outcomes.

EXPERIMENTAL DESIGN

A single-institution review identified 100 SBAs. Tumors were evaluated for MSI via MSIsensor and/or corresponding MMR protein expression via IHC staining. Germline DNA was analyzed for mutations in known cancer predisposition genes, including MMR (MLH1, MSH2, MSH6, PMS2, and EPCAM). Clinical variables were correlated with MMR/MSI status.

RESULTS

Twenty-six percent (26/100; 95% confidence interval, 18.4-35.4) of SBAs exhibited MMR deficiency (MMR-D). Lynch syndrome prevalence was 10% overall and 38.5% among MMR-D SBAs. Median age at SBA diagnosis was similar in non-Lynch syndrome MMR-D versus MMR-proficient (MMR-P) SBAs (65 vs. 61; P = 0.75), but significantly younger in Lynch syndrome (47.5 vs. 61; P = 0.03). The prevalence of synchronous/metachronous cancers was 9% (6/67) in MMR-P versus 34.6% (9/26) in MMR-D SBA, with 66.7% (6/9) of these in Lynch syndrome (P = 0.0002). In the MMR-P group, 52.2% (35/67) of patients presented with metastatic disease, compared with 23.1% (6/26) in the MMR-D group (P = 0.008). In MMR-P stage I/II patients, 88.2% (15/17) recurred, compared with 18.2% (2/11) in the MMR-D group (P = 0.0002).

CONCLUSIONS

When compared with MMR-P SBA, MMR-D SBA was associated with earlier stage disease and lower recurrence rates, similar to observations in colorectal cancer. With a 38.5% prevalence in MMR-D SBA, germline Lynch syndrome testing in MMR-D SBA is warranted.

Effectiveness of a dedicated small bowel neoplasia screening program by capsule endoscopy in Lynch syndrome: 5 years results from a tertiary care center

BACKGROUND AND AIMS

The role of small bowel neoplasia (SBN) screening in asymptomatic patients with Lynch syndrome (LS) is uncertain. The aim of our study was to assess the effectiveness of screening by capsule endoscopy (CE) in these patients.

METHODS

This study was an observational, analytical, and retrospective single-center study within the PRED-IdF network. All consecutive asymptomatic patients older than 35 years-old with confirmed LS and no personal history of SBN who started the screening from 2010-2015 were included. The baseline screening and 24 months follow-up were performed by CE. The CE diagnostic yield (positive tumor or polyp) and accuracy, using the follow-up as gold standard, were evaluated.

RESULTS

A total of 150 patients underwent the SBN screening program and 135 (52.7 ± 11.2 years-old, 37.8% male) met the inclusion criteria. The baseline CE diagnostic yield was 4.4% (3 polyps, 3 tumors) and the proximal small bowel was the most common location (n = 4, 66.7%). In total, 87 patients underwent follow-up and the diagnostic yield was 4.6%.Four patients were considered positive at follow-up (2 adenomas, 2 adenocarcinomas). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CE were 60%, 100%, 100%, 96.9%, and 97%, respectively.

CONCLUSIONS

CE is an accurate procedure for baseline screening of SBN in LS patients and may be efficient for follow-up procedures. However, the optimal starting age of screening and intervals of follow-up must be clarified.

Small Bowel Neoplasms: A Pictorial Review

Small bowel tumors are rare and account for approximately 3% of all gastrointestinal tumors in the United States. The incidence of small bowel neoplasms is rising-in particular, there is a rising incidence of small bowel carcinoid tumors. This may in part be due to small bowel lesion identification in an increasing number of cross-sectional imaging studies performed for other indications as well as increased use of advanced imaging techniques to assess specifically for small bowel disease. Diagnosis is a challenge owing to nonspecific clinical manifestation, rare occurrence, and low index of clinical suspicion. Yet, various small bowel neoplasms have characteristic imaging features at CT and MRI when optimal distention of the small bowel is achieved, correlating well with features seen in gross specimens. Understanding the imaging features of small bowel neoplasms is important to improve the radiologist's ability to diagnose and characterize small bowel neoplasms. Most small bowel tumors are clinically silent for long periods, and nearly half of the benign tumors are found incidentally during surgery or at cross-sectional imaging performed for other reasons. The authors review the imaging features of common benign and malignant small bowel neoplasms to aid the radiologist in diagnosis of small bowel tumors. ^©RSNA, 2020.

Duodenal tumor risk in Lynch syndrome

BACKGROUND AND AIMS

Lynch syndrome (LS) is associated with an increased risk of small bowel tumors but routine screening is not recommended in international guidelines. The aim of our study was to determinate the prevalence of duodenal tumors in a French cohort of LS patients.

METHODS

Patients carrying a germline pathogenic variant in a MMR gene, supported by our local network, in which at least one upper endoscopy had been performed, were included. We registered the occurrence of duodenal lesions in those patients.

RESULTS

154 LS patients were identified including respectively 85 MSH2 and 41 MLH1 mutated patients respectively. Seven out of 154 (4.5%) had at least one duodenal lesion. Median age at diagnosis was 58 years (range: 49-73). The twelve lesions locations were: descending duodenum (n = 7), genu inferius (n = 2), duodenal bulb (n = 1), ampulla (n = 1), fourth duodenum (n = 1). Three lesions were invasive adenocarcinomas. The incidence rate of duodenal lesions in patients with MSH2 or MLH1 pathogenic variants was respectively 7.1% (6 out of 85) and 2.4% (1 out of 41) emphasizing a trend toward increased risk of developing duodenal lesion in MSH2 mutated patients: OR: 5.17, IC95% (0.8-60.07), p = 0.1307.

CONCLUSION

Regarding this high prevalence rate, especially in MSH2 patients, regular duodenal screening during upper endoscopy should be considered in routine in LS patients.

Update on small bowel surveillance in hereditary colorectal cancer syndromes

Despite its rarity in the general population, small bowel adenocarcinoma risk is increased in individuals with hereditary colorectal cancer syndromes (HCCS). In the last decade, the advent of capsule endoscopy and device-assisted balloon enteroscopy procedures in patients with HCCS have allowed to investigate the whole small bowel, increasing the diagnostic yield of small bowel tumor. Nonetheless, there is a significant variability in the international guideline recommendations. The aim of this review is to provide an update on surveillance of small bowel in HCCS and to identify the key points for the clinical management of these patients.

Lynch syndrome-related small intestinal adenocarcinomas

Lynch syndrome is an autosomal-dominant disorder caused by defective DNA mismatch repair (MMR) genes and is associated with increased risk of malignancies in multiple organs. Small-intestinal adenocarcinomas are common initial manifestations of Lynch syndrome. To define the incidence and characteristics of Lynch syndrome-related small-intestinal adenocarcinomas, meticulous familial and clinical histories were obtained from 195 patients with small-intestinal adenocarcinoma, and MMR protein immunohistochemistry, microsatellite instability, MLH1 methylation, and germline mutational analyses were performed. Lynch syndrome was confirmed in eight patients (4%), all of whom had synchronous/metachronous malignancies without noticeable familial histories. Small-intestinal adenocarcinomas were the first clinical manifestation in 37% (3/8) of Lynch syndrome patients, and second malignancies developed within 5 years in 63% (5/8). The patients with accompanying Lynch syndrome were younger (≤50 years; P=0.04) and more likely to have mucinous adenocarcinomas (P=0.003), and tended to survive longer (P=0.11) than those with sporadic cases. A meticulous patient history taking, MMR protein immunolabeling, and germline MMR gene mutational analysis are important for the diagnosis of Lynch syndrome-related small-intestinal adenocarcinomas. Identifying Lynch syndrome in patients with small-intestinal adenocarcinoma can be beneficial for the early detection and treatment of additional Lynch syndrome-related cancers, especially in patients who are young or have mucinous adenocarcinomas.

Could the PD-1 Pathway Be a Potential Target for Treating Small Intestinal Adenocarcinoma?

OBJECTIVES

The programmed death 1 (PD-1) pathway is upregulated in the immune microenvironment of many cancers. In this study, we examined the PD-1 pathway and the immune microenvironment of small intestinal adenocarcinomas by immunohistochemistry.

METHODS

From our department pathology archives we identified 42 small intestinal adenocarcinomas from between 2000 and 2015, with blocks available for IHC studies. Tumors were immunohistochemically stained for CD3, CD4, CD8, CD20, PD-1, and programmed death ligand 1 (PD-L1) expression.

RESULTS

PD-1 was expressed by intratumoral and peritumoral lymphocytes in 35 of 42 (83%) cases. PD-L1 expression on tumor cells and immune cells was observed in seven of 42 (17%), and 18 of 42 (43%) cases, respectively. PD-L1 was mainly expressed by histiocytes capping cancerous glands/nests at the invasive front or by most tumor cells in medullary carcinomas. All the PD-L1+ tumors also expressed PD-1. The tumors expressing PD-L1 contained more CD3+, CD4+, and CD8+ T cells, but showed a lower CD4+/CD8+ ratio than those without expression of PD-L1.

CONCLUSIONS

PD-1 and PD-L1 are highly expressed by most small intestinal adenocarcinomas. Blockage of the PD-1 pathway should be evaluated in the treatment of small intestinal adenocarcinomas.

Management of small bowel polyps: A literature review

Despite the small bowel comprising 90% of the mucosal surface area of the gastrointestinal tract, it is a rare site for neoplasia and only accounts for a little over 3% of the tumors that arise in the digestive tract. Benign small bowel lesions include lipomas, lymphangiomas, leiomyomas, neurofibromas, nodular lymphoid hyperplasia and adenomas, many of which are precursors to malignant lesions. Several polyposis syndromes are associated with small bowel polyps as well, including familial adenomatous polyposis syndrome, lynch syndrome, Peutz-Jeghers syndrome, Cowden syndrome and juvenile polyposis syndrome. Our aim was to review non-malignant small bowel polyps and discuss the prevalence, typical location, clinical presentation, diagnosis, endoscopic and histologic description and lastly management of each of these lesions.

Incidence of small bowel neoplasia in Lynch syndrome assessed by video capsule endoscopy

BACKGROUND AND STUDY AIMS

Lynch syndrome (LS) patients have an increased risk of small bowel cancer. The question is whether surveillance will lead to early detection of (pre)malignant lesions. We recently reported on prevalence of small bowel neoplasia (SBN) in LS patients as assessed by video capsule endoscopy (VCE). The aim of this prospective study was to determine the incidence of SBN.

PATIENTS AND METHODS

Asymptomatic LS patients who underwent a VCE were invited to undergo a second VCE procedure 2 years later. If abnormalities or polypoid lesions larger than 1 cm were detected, subsequent endoscopic procedures were performed.

RESULTS

A total of 155 (78 %) of the initial 200 patients underwent a second VCE procedure after a mean of 2.2 (range 1 - 6) years. In 17 of the 155 (11 %) patients possibly significant lesions were detected, which required further investigation by means of gastroduodenoscopy (n = 8) or balloon-assisted endoscopy (n = 9). These procedures revealed no SBN.

CONCLUSION

No SBN was found after 2 years. Surveillance of the small bowel by VCE does not seem to be warranted in asymptomatic LS patients.

Childhood neuroendocrine tumours: a descriptive study revealing clues for genetic predisposition

BACKGROUND

Neuroendocrine tumours (NETs) are rare in children and limited data are available. We aimed to specify tumour and patient characteristics and to investigate the role of genetic predisposition in the aetiology of paediatric NETs.

METHODS

Using the Dutch Pathology Registry PALGA, we collected patient- and tumour data of paediatric NETs in the Netherlands between 1991 and 2013 (N=483).

RESULTS

The incidence of paediatric NETs in the Netherlands is 5.40 per one million per year. The majority of NETs were appendiceal tumours (N=441;91.3%). Additional surgery in appendiceal NETs was indicated in 89 patients, but performed in only 27 of these patients. Four out of five patients with pancreatic NETs were diagnosed with Von Hippel-Lindau disease (N=2) and Multiple Endocrine Neoplasia type 1 (N=2). In one patient with an appendiceal NET Familial Adenomatous Polyposis was diagnosed. On the basis of second primary tumours or other additional diagnoses, involvement of genetic predisposition was suggestive in several others.

CONCLUSIONS

We identified a significant number of patients with a confirmed or suspected tumour predisposition syndrome and show that paediatric pancreatic NETs in particular are associated with genetic syndromes. In addition, we conclude that treatment guidelines for appendiceal paediatric NETs need revision and improved implementation.

Chemoprevention trials of GI cancers in Asia

Cancers are among the leading causes of morbidity and mortality worldwide, with gastrointestinal (GI) luminal cancers accounting for a large proportion of cancer incidence. Chemoprevention of GI luminal cancers is important to reduce this cancer burden. Screening for and eradication of Helicobacter pylori (H. pylori) in areas with high gastric cancer incidence is a safe and effective strategy to decrease the incidence of gastric cancer. Eradication of H. pylori also seems to be effective in preventing metachronous cancer development after endoscopic resection of early gastric cancer. For the average risk individual, COX inhibitors may have a role in reducing the incidence of adenoma formation as well as colorectal cancer, bearing in mind its inherent risks. There is currently insufficient evidence to recommend a chemoprevention agent against esophageal and small intestine cancer.

Prevalence of small-bowel neoplasia in Lynch syndrome assessed by video capsule endoscopy

OBJECTIVE

The aim was to determine the prevalence of small-bowel neoplasia in asymptomatic patients with Lynch syndrome (LS) by video capsule endoscopy (VCE).

DESIGN

After obtaining informed consent, asymptomatic proven gene mutation carriers aged 35-70 years were included in this prospective multicentre study in the Netherlands. Patients with previous small-bowel surgery were excluded. After bowel preparation, VCE was performed. The videos were read by two independent investigators. If significant lesions were detected, an endoscopic procedure was subsequently performed to obtain histology and, if possible, remove the lesion.

RESULTS

In total, 200 patients (mean age 50 years (range 35-69), M/F 88/112), with proven mutations were included. These concerned MLH1 (n = 50), MSH2 (n = 68), MSH6 (n = 76), PMS2 (n = 3) and Epcam (n = 3) mutation carriers. In 95% of the procedures, caecal visualisation was achieved. Small-bowel neoplasia was detected in two patients: one adenocarcinoma (TisN0Mx) and one adenoma, both located in the duodenum. In another patient, a duodenal cancer (T2N0Mx) was diagnosed 7 months after a negative VCE. This was considered a lesion missed by VCE. All three neoplastic lesions were within reach of a conventional gastroduodenoscope. All patients with neoplasia were men, over 50 years of age and without a family history of small-bowel cancer.

CONCLUSIONS

The prevalence of small-bowel neoplasia in asymptomatic patients with LS was 1.5%. All neoplastic lesions were located in the duodenum and within reach of conventional gastroduodenoscopy. Although VCE has the potential to detect these neoplastic lesions, small-bowel neoplasia may be missed.

TRIAL REGISTRATION NUMBER

NCT00898768.

Prognostic relevance of lymph node ratio and total lymph node count for small bowel adenocarcinoma

BACKGROUND

Nodal metastasis is a known prognostic factor for small bowel adenocarcinoma. The goals of this study were to evaluate the number of lymph nodes (LNs) that should be retrieved and the impact of lymph node ratio (LNR) on survival.

METHODS

Surveillance, Epidemiology, and End Results was queried to identify patients with small bowel adenocarcinoma who underwent resection from 1988 to 2010. Survival was calculated with the Kaplan-Meier method. Multivariate analysis identified predictors of survival.

RESULTS

A total of 2,772 patients underwent resection with at least one node retrieved, and this sample included equal numbers of duodenal (n = 1,387) and jejunoileal (n = 1,386) adenocarcinomas. There were 1,371 patients with no nodal metastasis (N0, 49.4%), 928 N1 (33.5%), and 474 N2 (17.1%). The median numbers of LNs examined for duodenal and jejunoileal cancers were 9 and 8, respectively. Cut-point analysis demonstrated that harvesting at least 9 for jejunoileal and 5 LN for duodenal cancers resulted in the greatest survival difference. Increasing LNR at both sites was associated with decreased overall median survival (LNR = 0, 71 months; LNR 0-0.02, 35 months; LNR 0.21-0.4, 25 months; and LNR >0.4, 16 months; P < .001). Multivariate analysis confirmed number of LNs examined, T-stage, LN positivity, and LNR were independent predictors of survival.

CONCLUSION

LNR has a profound impact on survival in patients with small bowel adenocarcinoma. To achieve adequate staging, we recommend retrieving a minimum of 5 LN for duodenal and 9 LN for jejunoileal adenocarcinomas.

The analysis of microsatellite instability in extracolonic gastrointestinal malignancy

Microsatellite instability (MSI) is a genetic feature of sporadic and familial cancers of multiple sites and is related to defective mismatch repair (MMR) protein function. Lynch syndrome (LS) is a familial form of MMR deficiency that may present with a spectrum of MSI positive cancers including gastrointestinal (GI) malignancies. The incidence of high level MSI (MSI-H) in colorectal carcinoma is well defined in both familial and sporadic cases and these tumours portend a better overall prognosis in colorectal carcinoma (CRC). There are certain morphological features that suggest MSI-H CRC and international guidelines have been established for the evaluation of MSI in CRC. The prevalence and morphological features of extracolonic GI MSI-H tumours are less well documented. Furthermore, it is unclear whether the guidelines for the assessment of MSI in CRC are appropriate for application to extracolonic GI malignancies. This review aims to summarise the recent literature on MSI in extracolonic LS-related GI tract malignancies with special attention to the assessment of the MMR system by evaluation of specific microsatellite markers and/or immunohistochemical evaluation of MMR protein expression. The reported prevalence of sporadic and LS-related MSI-H tumours along with their associated unique morphological patterns and related prognostic or therapeutic implications will be discussed.

Guidelines for surveillance of individuals with constitutional mismatch repair-deficiency proposed by the European Consortium "Care for CMMR-D" (C4CMMR-D)

Lynch syndrome (LS) is an autosomal dominant disorder caused by a defect in one of the DNA mismatch repair genes: MLH1, MSH2, MSH6 and PMS2. In the last 15 years, an increasing number of patients have been described with biallelic mismatch repair gene mutations causing a syndrome referred to as 'constitutional mismatch repair-deficiency' (CMMR-D). The spectrum of cancers observed in this syndrome differs from that found in LS, as about half develop brain tumours, around half develop digestive tract cancers and a third develop haematological malignancies. Brain tumours and haematological malignancies are mainly diagnosed in the first decade of life, and colorectal cancer (CRC) and small bowel cancer in the second and third decades of life. Surveillance for CRC in patients with LS is very effective. Therefore, an important question is whether surveillance for the most common CMMR-D-associated cancers will also be effective. Recently, a new European consortium was established with the aim of improving care for patients with CMMR-D. At a workshop of this group held in Paris in June 2013, one of the issues addressed was the development of surveillance guidelines. In 1968, criteria were proposed by WHO that should be met prior to the implementation of screening programmes. These criteria were used to assess surveillance in CMMR-D. The evaluation showed that surveillance for CRC is the only part of the programme that largely complies with the WHO criteria. The values of all other suggested screening protocols are unknown. In particular, it is questionable whether surveillance for haematological malignancies improves the already favourable outcome for patients with these tumours. Based on the available knowledge and the discussions at the workshop, the European consortium proposed a surveillance protocol. Prospective collection of all results of the surveillance is needed to evaluate the effectiveness of the programme.

Telomeres and telomere dynamics: relevance to cancers of the GI tract

Aberrations in telomere length and telomere maintenance contribute to cancer development. In this article, we review the basic principles of telomere length in normal and tumor tissue and the presence of the two main telomere maintenance pathways as they pertain to gastrointestinal tract cancer. Peripheral blood telomeres are shorter in patients with many types of gastrointestinal tract cancers. Telomere length in tumor DNA also appears to shorten early in cancer development. Tumor telomere shortening is often accompanied by telomerase activation to protect genetically damaged DNA from normal cell senescence or apoptosis, allowing immortalized but damaged DNA to persist. Alternative lengthening of telomeres is another mechanism used by cancer to maintain telomere length in cancer cells. Telomerase and alternative lengthening of telomeres activators and inhibitors may become important chemopreventive or chemotherapeutic agents as our understanding of telomere biology, specific telomere-related phenotypes and its relationship to carcinogenesis increases.

Small bowel adenocarcinomas--existing evidence and evolving paradigms

Small bowel cancers account for 3% of all gastrointestinal malignancies and small bowel adenocarcinomas represent a third of all small bowel cancers. Rarity of small bowel adenocarcinomas restricts molecular understanding and presents unique diagnostic and therapeutic challenges. Better cross-sectional imaging techniques and development of enteroscopy and capsule endoscopy have facilitated earlier and more-accurate diagnosis. Surgical resection remains the mainstay of therapy for locoregional disease. In the metastatic setting, fluoropyrimidine and oxaliplatin-based chemotherapy has shown clinical benefit in prospective non-randomized trials. Although frequently grouped under the same therapeutic umbrella as large bowel adenocarcinomas, small bowel adenocarcinomas are distinct clinical and molecular entities. Recent progress in molecular characterization has aided our understanding of the pathogenesis of these tumours and holds potential for prospective development of novel targeted therapies. Multi-institutional collaborative efforts directed towards cogent understanding of tumour biology and designing sensible clinical trials are essential for developing improved therapeutic strategies. In this Review, we endeavour to outline an evidence-based approach to present-day management of small bowel adenocarcinoma, describe contemporary challenges and uncover evolving paradigms in the management of these rare 'orphan' neoplasias.

10 rare tumors that warrant a genetics referral

The number of described cancer susceptibility syndromes continues to grow, as does our knowledge on how to manage these syndromes with the aim of early detection and cancer prevention. Oncologists now have greater responsibility to recognize patterns of cancer that warrant referral for a genetics consultation. While some patterns of common cancers are easy to recognize as related to hereditary cancer syndromes, there are a number of rare tumors that are highly associated with cancer syndromes yet are often overlooked given their infrequency. We present a review of ten rare tumors that are strongly associated with hereditary cancer predisposition syndromes: adrenocortical carcinoma, carcinoid tumors, diffuse gastric cancer, fallopian tube/primary peritoneal cancer, leiomyosarcoma, medullary thyroid cancer, paraganglioma/pheochromocytoma, renal cell carcinoma of chromophobe, hybrid oncocytoic, or oncocytoma histology, sebaceous carcinoma, and sex cord tumors with annular tubules. This review will serve as a guide for oncologists to assist in the recognition of rare tumors that warrant referral for a genetic consultation.

Risks of primary extracolonic cancers following colorectal cancer in lynch syndrome

BACKGROUND

Lynch syndrome is a highly penetrant cancer predisposition syndrome caused by germline mutations in DNA mismatch repair (MMR) genes. We estimated the risks of primary cancers other than colorectal cancer following a diagnosis of colorectal cancer in mutation carriers.

METHODS

We obtained data from the Colon Cancer Family Registry for 764 carriers of an MMR gene mutation (316 MLH1, 357 MSH2, 49 MSH6, and 42 PMS2), who had a previous diagnosis of colorectal cancer. The Kaplan-Meier method was used to estimate their cumulative risk of cancers 10 and 20 years after colorectal cancer. We estimated the age-, sex-, country- and calendar period-specific standardized incidence ratios (SIRs) of cancers following colorectal cancer, compared with the general population.

RESULTS

Following colorectal cancer, carriers of MMR gene mutations had the following 10-year risk of cancers in other organs: kidney, renal pelvis, ureter, and bladder (2%, 95% confidence interval [CI] = 1% to 3%); small intestine, stomach, and hepatobiliary tract (1%, 95% CI = 0.2% to 2%); prostate (3%, 95% CI = 1% to 5%); endometrium (12%, 95% CI = 8% to 17%); breast (2%, 95% CI = 1% to 4%); and ovary (1%, 95% CI = 0% to 2%). They were at elevated risk compared with the general population: cancers of the kidney, renal pelvis, and ureter (SIR = 12.54, 95% CI = 7.97 to 17.94), urinary bladder (SIR = 7.22, 95% CI = 4.08 to 10.99), small intestine (SIR = 72.68, 95% CI = 39.95 to 111.29), stomach (SIR = 5.65, 95% CI = 2.32 to 9.69), and hepatobiliary tract (SIR = 5.94, 95% CI = 1.81 to 10.94) for both sexes; cancer of the prostate (SIR = 2.05, 95% CI = 1.23 to 3.01), endometrium (SIR = 40.23, 95% CI = 27.91 to 56.06), breast (SIR = 1.76, 95% CI = 1.07 to 2.59), and ovary (SIR = 4.19, 95% CI = 1.28 to 7.97).

CONCLUSION

Carriers of MMR gene mutations who have already had a colorectal cancer are at increased risk of a greater range of cancers than the recognized spectrum of Lynch syndrome cancers, including breast and prostate cancers.

Cross-Sectional Imaging of Small Bowel Malignancies

Small bowel malignancies are rare neoplasms, usually inaccessible to conventional endoscopy but detectable in many cases by cross-sectional imaging. Modern multidetector computed tomographies permit accurate diagnosis, complete pretreatment staging, and follow-up of these lesions. In this review, we describe the cross-sectional imaging features of the most frequent histologic subtypes of the small bowel malignancies.

Small bowel endoscopy in familial adenomatous polyposis and Lynch syndrome

Patients with familial adenomatous polyposis (FAP) and patients with Lynch syndrome have an increased risk of developing small intestinal neoplasia. In both conditions, the lifetime risk to develop small bowel cancer is estimated to be around 5%. In FAP, this risk is associated with the degree of duodenal polyposis, classically assessed by the Spigelman classification. For this reason, gastroduodenal surveillance with forward-viewing and side-viewing endoscopy is generally recommended. Studies using video capsule endoscopy and balloon-assisted enteroscopy in FAP patients have revealed that jejunal and ileal polyps occur frequently in FAP, especially in those with extensive duodenal polyposis. Nevertheless, the clinical relevance of small bowel polyps beyond the duodenum appears to be limited. Compared to FAP, little is known about the prevalence and natural history of small bowel neoplasia in Lynch syndrome. Surveillance of the small bowel is not recommended in Lynch syndrome, although recent data using capsule endoscopy provided promising results.

Clinicopathological features and management of cancers in lynch syndrome

Lynch syndrome (LS) is characterized by an autosomal dominant inheritance of the early onset of colorectal cancer (CRC) and endometrial cancer, as well as increased risk for several other cancers including gastric, urinary tract, ovarian, small bowel, biliary tract, and brain tumors. The syndrome is due to a mutation in one of the four DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, or PMS2. The majority of LS patients and families can now be identified, and the underlying mutation detected using genetic diagnostics. Regular surveillance for CRC and endometrial cancer has proved beneficial for mutation carriers. However, screening for other tumors is also recommended even though experiences in the screening of these tumors is limited. Prophylactic colectomy, prophylactic hysterectomy, and bilateral salpingo-oophorectomy may be reasonable options for selected patients with LS. This paper describes the features and management of LS.

Evidence for breast cancer as an integral part of Lynch syndrome

Lynch syndrome, an autosomal dominant cancer predisposition caused by mutations in DNA mismatch repair (MMR) genes, mainly mainly mutL homolog 1, OMIM 120436 (MLH1) and mutS homolog 2, OMIM 609309 (MSH2), encompasses a tumor spectrum including primarily gastrointestinal, endometrial, and ovarian cancer. This study aimed at clarifying the heavily debated issue of breast cancer being part of Lynch syndrome. Detailed clinical data on cancer occurrence in Swiss female MLH1/MSH2 mutation carriers were gathered, all available breast cancer specimens assessed for molecular evidence for MMR deficiency (i.e., microsatellite instability (MSI), MMR protein expression, and somatic (epi)genetic MMR gene alterations) and compiled with the scarce molecular data available from the literature. Seventy unrelated Swiss Lynch syndrome families were investigated comprising 632 female family members at risk of which 92 were genetically verified mutation carriers (52 MLH1 and 40 MSH2). On contrast to endometrial and ovarian cancer, which occurred significantly more often and at younger age in MLH1/MSH2 mutation carriers (median 50.5 and 49.0 years; P < 0.00001), overall cumulative breast cancer incidence closely mirrored the one in the Swiss population (56.5 years). Six (85.7%) of seven breast cancer specimens available for molecular investigations displayed the hallmarks of MMR deficiency. Combined with data from the literature, MSI was present in 26 (70.3%) of 37 and altered MMR protein expression in 16 (72.7%) of 22 breast cancer specimens from MLH1/MSH2 mutation carriers. These findings, thus, provide strong molecular evidence for a pivotal role of MMR deficiency in breast cancer development in Lynch syndrome.

Small bowel carcinoma in young patient detected by double-balloon enteroscopy

A 17-year old female presented with a chief complaint of melena and epigastric pain. She had a family history of colon cancer, her mother having been diagnosed with hereditary nonpolyposis colorectal carcinoma (HNPCC). After close examination including double-balloon enteroscopy, the patient was diagnosed with small bowel carcinoma, in spite of her young age. Here we report this rare case of small bowel carcinoma in a young patient with a family history of HNPCC.

Epidemiology of cancer of the small intestine

Cancer of the small intestine is very uncommon. There are 4 main histological subtypes: adenocarcinomas, carcinoid tumors, lymphoma and sarcoma. The incidence of small intestine cancer has increased over the past several decades with a four-fold increase for carcinoid tumors, less dramatic rises for adenocarcinoma and lymphoma and stable sarcoma rates. Very little is known about its etiology. An increased risk has been noted for individuals with Crohn’s disease, celiac disease, adenoma, familial adenomatous polyposis and Peutz-Jeghers syndrome. Several behavioral risk factors including consumption of red or smoked meat, saturated fat, obesity and smoking have been suggested. The prognosis for carcinomas of the small intestine cancer is poor (5 years relative survival < 30%), better for lymphomas and sarcomas, and best for carcinoid tumors. There has been no significant change in long-term survival rates for any of the 4 histological subtypes. Currently, with the possible exceptions of obesity and cigarette smoking, there are no established modifiable risk factors which might provide the foundation for a prevention program aimed at reducing the incidence and mortality of cancers of the small intestine. More research with better quality and sufficient statistical power is needed to get better understanding of the etiology and biology of this cancer. In addition, more studies should be done to assess not only exposures of interest, but also host susceptibility.

Personalized genomic medicine

Personalized medicine provide to physicians a molecular makeup of each patient. Looking at the patient on this level helps the physician get a profile of the patient's genetic distinction, or mapping. By investigating this genetic profile, medical professionals are then able to select patients, and use the found information to plan out a course of treatment that is much more in step with the way their body works. Personalize medicine is a direct extension of the genomic medicine that use genetic information to prevent or treat disease in adults or their children.

[A case of locally invasive obstructive jejunal cancer with curative resection after stenting and chemotherapy]

Small bowel adenocarcinoma is a relatively rare malignancy. In Korea, 13.1% of small bowel adenocarcinoma occurs in the jejunum. The absence of effective screening methods and relatively obscure symptoms contribute to the higher percentage of advanced cases at the time of diagnosis. Although curative resection is the mainstay of treatment, it is often impossible. Chemotherapy and radiotherapy have shown a disappointing treatment result for advanced staged small bowel adenocarcinoma. We report a 54-year-old woman with locally invasive jejunal cancer who underwent curative resection after stent insertion with enteroscopy and chemotherapy.

High-resolution array comparative genomic hybridization in sporadic and celiac disease-related small bowel adenocarcinomas

PURPOSE

The molecular pathogenesis of small intestinal adenocarcinomas is not well understood. Understanding the molecular characteristics of small bowel adenocarcinoma may lead to more effective patient treatment.

EXPERIMENTAL DESIGN

Forty-eight small bowel adenocarcinomas (33 non-celiac disease related and 15 celiac disease related) were characterized for chromosomal aberrations by high-resolution array comparative hybridization, microsatellite instability, and APC promoter methylation and mutation status. Findings were compared with clinicopathologic and survival data. Furthermore, molecular alterations were compared between celiac disease-related and non-celiac disease-related small bowel adenocarcinomas.

RESULTS

DNA copy number changes were observed in 77% small bowel adenocarcinomas. The most frequent DNA copy number changes found were gains on 5p15.33-5p12, 7p22.3-7q11.21, 7q21.2-7q21.3, 7q22.1-7q34, 7q36.1, 7q36.3, 8q11.21-8q24.3, 9q34.11-9q34.3, 13q11-13q34, 16p13.3, 16p11.2, 19q13.2, and 20p13-20q13.33, and losses on 4p13-4q35.2, 5q15-5q21.1, and 21p11.2-21q22.11. Seven highly amplified regions were identified on 6p21.1, 7q21.1, 8p23.1, 11p13, 16p11.2, 17q12-q21.1, and 19q13.2. Celiac disease-related and non-celiac disease-related small bowel adenocarcinomas displayed similar chromosomal aberrations. Promoter hypermethylation of the APC gene was found in 48% non-celiac disease-related and 73% celiac disease-related small bowel adenocarcinomas. No nonsense mutations were found. Thirty-three percent of non-celiac disease-related small bowel adenocarcinomas showed microsatellite instability, whereas 67% of celiac disease-related small bowel adenocarcinomas were microsatellite unstable.

CONCLUSIONS

Our study characterized chromosomal aberrations and amplifications involved in small bowel adenocarcinoma. At the chromosomal level, celiac disease-related and non-celiac disease-related small bowel adenocarcinomas did not differ. A defect in the mismatch repair pathways seems to be more common in celiac disease-related than in non-celiac disease-related small bowel adenocarcinomas. In contrast to colon and gastric cancers, no APC nonsense mutations were found in small bowel adenocarcinoma. However, APC promoter methylation seems to be a common event in celiac disease-related small bowel adenocarcinoma. Clin Cancer Res; 16(5); 1391-401.

Cancer risk in MLH1, MSH2 and MSH6 mutation carriers; different risk profiles may influence clinical management

BACKGROUND

Lynch syndrome (LS) is associated with a high risk for colorectal cancer (CRC) and extracolonic malignancies, such as endometrial carcinoma (EC). The risk is dependent of the affected mismatch repair gene. The aim of the present study was to calculate the cumulative risk of LS related cancers in proven MLH1, MSH2 and MSH6 mutation carriers.

METHODS

The studypopulation consisted out of 67 proven LS families. Clinical information including mutation status and tumour diagnosis was collected. Cumulative risks were calculated and compared using Kaplan Meier survival analysis.

RESULTS

MSH6 mutation carriers, both males and females had the lowest risk for developing CRC at age 70 years, 54% and 30% respectively and the age of onset was delayed by 3-5 years in males. With respect to endometrial carcinoma, female MSH6 mutation carriers had the highest risk at age 70 years (61%) compared to MLH1 (25%) and MSH2 (49%). Also, the age of EC onset was delayed by 5-10 years in comparison with MLH1 and MSH2.

CONCLUSIONS

Although the cumulative lifetime risk of LS related cancer is similar, MLH1, MSH2 and MSH6 mutations seem to cause distinguishable cancer risk profiles. Female MSH6 mutation carriers have a lower CRC risk and a higher risk for developing endometrial carcinoma. As a consequence, surveillance colonoscopy starting at age 30 years instead of 20-25 years is more suitable. Also, prophylactic hysterectomy may be more indicated in female MSH6 mutation carriers compared to MLH1 and MSH2 mutation carriers.

Adenocarcinoma of the small bowel: a surgical dilemma

Malignant tumors of the small intestine are among the rarest types of gastrointestinal cancers. Due to their infrequent occurrence and the multitude of tumor types (viz, adenocarcinomas, carcinoids, sarcomas, and lymphomas), not much is known about their natural history and presentation, and there is often delay in the diagnosis. Adenocarcinoma is the commonest histologic type of small bowel cancer. There are no prospective randomized trials that have elucidated the best diagnostic and therapeutic options for this rare condition. In this article, a case of adenocarcinoma of the jejunum presenting as an abdominal lump is presented, along with a review of the literature.

Adenocarcinoma of the small bowel: a surgical dilemma

Malignant tumors of the small intestine are among the rarest types of gastrointestinal cancers. Due to their infrequent occurrence and the multitude of tumor types (viz, adenocarcinomas, carcinoids, sarcomas, and lymphomas), not much is known about their natural history and presentation, and there is often delay in the diagnosis. Adenocarcinoma is the commonest histologic type of small bowel cancer. There are no prospective randomized trials that have elucidated the best diagnostic and therapeutic options for this rare condition. In this article, a case of adenocarcinoma of the jejunum presenting as an abdominal lump is presented, along with a review of the literature.

Management of extracolonic tumours in patients with Lynch syndrome

Hereditary nonpolyposis colorectal cancer, or Lynch syndrome, is responsible for 2-3% of all colorectal cancers. Lynch syndrome is also associated with a high risk of extracolonic cancers, including endometrial, stomach, small bowel, pancreas, biliary tract, ovary, urinary tract, brain, and skin cancer. In this Review, we discuss the risks, surveillance tests, and guidelines for the management of extracolonic tumours associated with Lynch syndrome. For all types of extracolonic cancer, evidence supporting surveillance is scarce. A benefit of surveillance is evident only for endometrial cancer, where transvaginal ultrasound and endometrial sampling detect tumours in early stages. Surveillance is generally recommended for urinary tract and gastric cancer, especially in families with more than one member with these types of cancer. For the other types of cancer, surveillance is typically not recommended. Prophylactic hysterectomy and bilateral salpingo-oophorectomy should be considered for women with Lynch syndrome who are past childbearing age, especially during surgery for colorectal cancer. No data show efficacy of chemopreventive drugs in reducing the risk of extracolonic cancers for patients with Lynch syndrome.

The epidemiology and pathogenesis of neoplasia in the small intestine

PURPOSE

The mucosa of the small intestine encompasses about 90% of the luminal surface area of the digestive system, but only 2% of the total annual gastrointestinal cancer incidence in the United States.

METHODS

The remarkable contrast in age-standardized cancer incidence between the small and large intestine has been reviewed with respect to the cell type patterns, demographic features, and molecular characteristics of neoplasms.

RESULTS

Particularly noteworthy is the predominance of adenocarcinoma in the colon, which exceeds 98% of the total incidence by cell type, in contrast to that of 30% to 40% in the small intestine, resulting in an age-standardized ratio of rates exceeding 50-fold. The prevalence of adenomas and carcinomas is most prominent in the duodenum and proximal jejunum. The positive correlation in global incidence rates of small and large intestinal neoplasms and the reciprocal increases in risk of second primary adenocarcinomas suggest that there are common environmental risk factors. The pathophysiology of Crohn inflammatory bowel disease and the elevated risk of adenocarcinoma demonstrate the significance of the impaired integrity of the mucosal barrier and of aberrant immune responses to luminal indigenous and potentially pathogenic microorganisms.

CONCLUSION

In advancing a putative mechanism for the contrasting mucosal susceptibilities of the small and large intestine, substantial differences are underscored in the diverse taxonomy, concentration and metabolic activity of anaerobic organisms, rate of intestinal transit, changing pH, and the enterohepatic recycling and metabolism of bile acids. Experimental and epidemiologic studies are cited that suggest that the changing microecology, particularly in the colon, is associated with enhanced metabolic activation of ingested and endogenously formed procarcinogenic substrates.

[Hereditary colorectal cancer]

One of the main challenges in the clinical management of familial colorectal cancer (CRC) remains the overlap of syndromes with different underlying genetic causes and the differentiated risk management of colorectal and associated malignancies. The Lynch syndrome (hereditary non-polyposis colorectal cancer, HNPCC) is characterized by the development of colorectal, endometrial, gastric and other cancers and is caused by a mutation in one of the mismatch repair (MMR) genes. Microsatellite instability (MSI) and/or immunohistochemistry (IHC) are important prognostic factors and may predict the response to chemotherapy. Familial adenomatous polyposis (FAP) may be seen as a counterpart to Lynch syndrome, responsible for <1% of all CRC cases. Recently the MUTYH gene has been identified as a further polyposis gene. The associated disorder has been termed MYH-associated polyposis (MAP) and displays an autosomal recessive pattern of inheritance. For clinical management, distinguishing between Lynch syndrome, attenuated FAP and MAP is important for risk assessment, surveillance recommendations and indication for prophylactic surgery.

Prognostic factors in primary adenocarcinoma of the small intestine: 13-year single institution experience

Background

Adenocarcinoma of the small bowel is a relatively rare malignancy as compared to the other malignancies of the gastrointestinal tract. Nonspecific presentation and infrequent occurrence often leads to a delay in diagnosis and consequent poor prognosis. Various other factors are of prognostic importance while managing these tumors.

Methods

The medical records of a total of 27 patients treated for adenocarcinoma of the small bowel at Providence Hospital and Medical Centers from year 1990 through 2003 were reviewed retrospectively. Data were analyzed using SPSS software (version 10.0; SPSS, Inc., Chicago, IL). Survival analyses were calculated using the Kaplan Meier method with the log rank test to assess the statistical significance. The socio-demographics (age, gender) were calculated using frequency analyses.

Results

The patients included nine males and eighteen females with a median age at diagnosis of 62 years. Only 48% of the patients had an accurate preoperative diagnosis while another 33% had a diagnosis suspicious of small bowel malignancy. None of the patients presented in stage 1. The cumulative five-year survival was 30% while the median survival was 3.3 years. There was no 30-day mortality in the postoperative period in our series.

Conclusion

The univariate analysis demonstrated that tumor grade, stage at presentation, lymph nodal metastasis and resection margins were significant predictors of survival.

Chromosomal and methylation alterations in sporadic and familial adenomatous polyposis-related duodenal carcinomas

Primary carcinomas of the small intestine are rare and the mechanism of their pathogenesis is poorly understood. Patients with familial adenomatous polyposis (FAP) have a high risk of developing duodenal carcinomas. The aim of this study is to gain more insight into the development of duodenal carcinomas. Therefore, five FAP-related duodenal carcinomas were characterized for chromosomal and methylation alterations, which were compared to those observed in sporadic duodenal carcinomas. Comparative genomic hybridization (CGH) and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was performed in 10 primary sporadic and five primary FAP-related duodenal carcinomas. In the FAP-related carcinomas, frequent gains were observed on chromosomes 8, 17 and 19, whereas in sporadic carcinomas they occurred on chromosomes 8, 12, 13 and 20. In 60% of the sporadic carcinomas, gains in the regions of chromosome 12 were observed which were absent in the FAP-related carcinomas (P=0.04). Hypermethylation was observed in the immunoglobulin superfamily genes member 4 (IGSF4), TIMP metallopeptidase inhibitor 3 (TIMP3), Estrogen receptor 1 (ESR1), adenomatous polyposis coli (APC), H-cadherin (CDH13) and paired box gene 6 (PAX6) genes. Hypermethylation of PAX6 was only observed in FAP-related carcinomas (3/5) and not in sporadic carcinomas (P=0.02). In conclusion, in contrast to sporadic duodenal carcinomas, gains on chromosome 12 were not observed in duodenal carcinomas of patients with FAP. Identification of the genes in these regions of chromosome 12 could lead to a better understanding of the carcinogenesis pathways leading to sporadic and FAP-related duodenal carcinomas. Furthermore, hypermethylation seems to be a general feature of both FAP-related duodenal carcinomas as well as sporadic duodenal carcinomas with the exception of the PAX6 gene, which is methylated only in FAP-related carcinomas.

Review article: Detection and management of hereditary non-polyposis colorectal cancer (Lynch syndrome)

BACKGROUND

The most common hereditary colorectal cancer syndrome is hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome. Diagnosis of this syndrome is difficult, because of lack of specific diagnostic features.

AIM

To discuss the diagnostic criteria and laboratory work up for HNPCC. Furthermore, surveillance programs for HNPCC and treatment of HNPCC associated colorectal cancer are discussed.

RESULTS

Current diagnostic criteria, including the Amsterdam II and Bethesda criteria, are suboptimal for the detection of HNPCC. Molecular screening by microsatellite instability (MSI) and immunohistochemistry (IHC) is useful in the diagnosis of HNPCC. Both techniques have a higher sensitivity compared to the Amsterdam II and Bethesda criteria. A combination of both MSI and IHC provides the most optimal selection for mutation analysis. After identification of a mutation in an affected individual, genetic counselling and presymptomatic mutation analysis should be offered to relatives. Furthermore, colonoscopic surveillance should be performed in proven mutation carriers.

CONCLUSIONS

Identification of HNPCC is a clinical challenge involving many clinicians. Identification of persons at risk can be achieved by a combination of a detailed family history, testing with molecular and mutation analysis.