predisposes to bacterial translocation through the bowel wall.

BACKGROUND Subjects with a positive family history of colorectal cancer (CRC) have an increased risk of developing CRC themselves. This risk depends on the number of affected relatives and the age at diagnosis. AIM The aim of this study was to assess the prevalence of a positive family history of CRC, within a random cohort among the dutch population. METHODS A total of 5072 subjects aged between 45 and 70 years were invited to fill in an anonymous questionnaire about the occurrence of CRC in their first-degree relatives (FDR). RESULTS The questionnaire was returned by 3973 subjects (78.3%). Thirty responders (0.8%) had CRC themselves. Of all unaffected responders, 441 (11.2%) subjects reported a positive family history of CRC. Ninety (2.3%) responders reported having an FDR with CRC diagnosed before the age of 50, or reported two or more FDRs with CRC. CONCLUSION The prevalence of a positive family history of CRC is substantial. Identification of this high-risk group by obtaining a thorough family history is the first step in targeting preventive measures.

Background & Aims: Lynch syndrome family members have a high risk of developing colorectal (CRC), endometrial (EC), and other cancers. A large-scale surveillance program was introduced in The Netherlands in the late 1980s. The aims of the study were to evaluate the effectiveness of this program by assessing mortality because of CRC and EC before and after 1990 and to compare mortality because of all cancers (except CRC/EC) with mortality in the general population. Methods: Family members with at least 50% probability of being a carrier were selected for the study. The standardized mortality ratio (SMR) because of cancer and the absolute excess risk of death (AER) were calculated. Results: In the total cohort (N = 2788), 445 subjects had died because of cancer. The 3 most frequent causes of cancer-related deaths were CRC (50.3%), EC (6.7%), and brain tumors (6.7%). A significant decrease (70%) in SMR for CRC over time was observed (P <.001); the SMR for EC showed no decreasing trend over time. A significantly increased SMR was found for cancer of the small bowel (SMR = 18.3), brain (SMR = 9.1), kidney/ureter (SMR = 5.9), ovarium (SMR = 2.3), pancreas (SMR = 2.2), and stomach (SMR = 2.1). The AER was significantly increased for brain tumors only. Conclusions: Since the introduction of surveillance, the mortality because of CRC has decreased. Except for brain tumors, we did not find a significantly increased AER for tumors other than CRC/EC.

ABSTRACT diagnostic workup of familial colorectal cancer is an elaborate and time consuming process in which the family and several medical specialists closely collaborate. However, establishing a diagnosis can be very rewarding. If a mutation is detected in the family, a satisfactory explanation can be provided for an accumulation of tumors at young age, and often of untimely death. Appropriate presymptomatic testing can be offered to reduce mortality among at-risk family members, and relatives not at risk can avoid uncertainty and needlessly intensive surveillance. We show the differential diagnostic considerations when an individual with a family history of colorectal carcinoma is encountered, with emphasis on Lynch syndrome (Hereditary Nonpolyposis Colorectal Carcinoma [HNPCC]). Practical recommendations for laboratory workup of suspected Lynch syndrome, including analysis of tumor tissue by microsatellite instability analysis and immunohistochemistry, and germline DNA analysis are given. Furthermore, the clinical management after a molecular diagnosis has been made is described. The diagnostic scheme presented here allows efficient and effective analysis of colorectal carcinoma cases with (suspected) Lynch syndrome, making optimal use of currently available technology.

INTRODUCTION:Lynch syndrome families have a substantial risk of developing colorectal cancer (CRC). The recommended surveillance protocol includes colonoscopy every 2 years from age 20-25 years. It is yet unknown whether annual screening of patients aged 40-60 years is more effective than bi-annual screening, whether patients who had an adenoma removed should be re-examined after a year and whether surveillance of second-degree relatives is indicated. The aim of this study was to address these issues.METHODS:All carriers of a mismatch repair gene mutation who participated in the surveillance program were selected from the Dutch Lynch syndrome registry. The results of colonoscopy were prospectively collected.RESULTS:A total of 666 mutation carriers were identified in 110 families. Fourty-one CRCs were detected during endoscopic follow-up, of which 34 (83%) were diagnosed between age 40 and 60 years. In five of 34 patients, CRC was diagnosed within 1 year after colonoscopy, eight cancers were diagnosed between 1 and 2 years and the remaining tumors more than 2 years after colonoscopy. All eight CRCs detected between 1 and 2 years were at local stage. At least one adenoma was diagnosed at 141 examinations. The risk of developing CRC during follow-up in carriers with an adenoma was similar as in carriers without an adenoma at the previous colonoscopy. 280 parent-child couples with at least one Lynch syndrome-related carcinoma were identified in 110 families. In only 19 (6.8%) of these couples, CRC developed earlier in the child than an Lynch syndrome-associated cancer in the parent.CONCLUSION:The current surveillance protocol, i.e., bi-annual colonoscopy in first-degree relatives independent of age and endoscopic findings, appears to be appropriate.

OBJECTIVES:We evaluated the prevalence and characteristics of adenomas in a young population not genetically predisposed for the development of colorectal cancer (CRC). METHODS:The databases of the Dutch Hereditary Colorectal Cancer Registry were used. The study population included patients (n = 444) who had regular endoscopy until mutation analysis revealed they did not carry the (Adenomatous Polyposis Coli (APC)/Mismatch Repair) gene defect identified in their family. RESULTS:At first colonoscopy (n = 342; 50% males, mean age 37 yr) a total of 19 adenomas (10 males, mean age 50 yr, range 24-91 yr) and two CRCs (2 males, age 49 and 72 yr) were identified, and at first sigmoidoscopy (n = 102; 53% males, mean age 29 yr) three adenomas (2 males, age 8, 40, and 41 yr) were found. A second colonoscopy was performed in 14 patients with, and in 162 patients without an adenoma. Three of 14 patients (21%) developed a new adenoma (all >50 yr) and 8 of 162 (5%) patients developed their first adenoma during follow-up. In the colonoscopy group, the cumulative proportion of patients free of adenomas at age 50 yr was 86%. Of all adenomas diagnosed during colonoscopy (n = 49), 65% were located distal from the flexura lienalis. Of the adenomas detected during all endoscopies (n = 53), 9.8% were > or =7 mm, 7.5% showed high-grade dysplasia, and 7.5% showed tubulovillous features. CONCLUSIONS:On the basis of our findings during colonoscopy we conclude that the risk of developing adenomas/CRC in young individuals without genetic risk factors is low. Adenoma surveillance programs should focus on young individuals with a positive family (or personal) history for adenomas/CRC, or on individuals >50 yr.

Hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome) is a dominantly inherited syndrome characterized by the development of colorectal cancer, endometrial cancer and other cancers and the presence of microsatellite instability (MSI) in tumors. The Bethesda guidelines have been proposed for the identification of families suspected of HNPCC that require further molecular analysis. We have evaluated the yield of MSI-analysis in a large series of Dutch families suspected of HNPCC. We also analysed whether the loss of mismatch repair (MMR) protein detected by immunohistochemistry (IHC) of colorectal cancer (CRC) and endometrial cancer correlated with the presence of MSI and/or a MMR gene mutation. The results showed that the Bethesda criteria with a few modifications are appropriate to identify families eligible for genetic testing. In addition, we found that MSI and IHC-analysis of CRC using antibodies against MLH1, MSH2, MSH6 and PMS2 proteins are equally effective for identifying carriers of the known MMR gene defects. However, as long as the role of other putative MMR genes in hereditary CRC has not been elucidated, IHC-analysis cannot completely replace MSI. For this reason, we prefer MSI-analysis as first step in families suspected of HNPCC. On the other hand, in families fulfilling the revised Amsterdam criteria in which the probability of detecting a mutation is relatively high, we would recommend IHC as first diagnostic step because the result might predict the specific underlying MMR gene mutation. MSI or IHC-analysis of endometrial cancer alone was found to be less sensitive compared with these tests performed in colorectal cancer. Therefore, probably the best approach in the analysis of this cancer is to perform both techniques. The identification of HNPCC is important as it makes it possible to target effective preventative measures. Our studies showed that MSI and IHC analysis of colorectal and endometrial cancer, are reliable cost-effective tools that can be used to identify patients with HNPCC.

Background & Aims: The adenoma-carcinoma sequence in hereditary nonpolyposis colorectal cancer (HNPCC) is accelerated. It remains unknown whether the mismatch repair (MMR) defect also promotes the development of adenomas. The aim of this study was to compare the risk of developing colorectal adenoma and carcinoma in HNPCC carriers and noncarriers (controls) and to compare the features of adenomas in both groups. Methods: Eighty-six families with a known MMR gene mutation from the Dutch HNPCC Registry were analyzed. Subjects with known mutation status with colonoscopies performed for the purpose of surveillance were selected for this study. Information on the surveillance examinations was obtained from medical reports. The histology of all adenomas was confirmed. Immunohistochemistry was performed in a subgroup of adenomas. Results: We identified 249 carriers and 247 controls. The proportion of subjects free of an adenoma at the age of 60 years was 29.7% for carriers and 70.8% for controls (P < 0.05). The adenomas in carriers were larger, and a higher proportion had villous components and/or high-grade dysplasia (P < 0.05, all analyses). The adenomas and carcinomas of the carriers were located predominantly in the proximal colon. Most adenomas showed absent staining of the MMR proteins. Conclusions: This study indicates that the MMR defect is involved in the early stages of development of adenomas. We recommend immunohistochemical staining of large adenomas with high-grade dysplasia in young patients (younger than 50 years) to identify patients with suspected HNPCC.

Anja Wagner 2, *, Alicia Barrows *, Juul Wijnen, Heleen van der Klift, Patrick Franken, Paul Verkuijlen, Hidewaki Nakagawa, Marjan Geugien, Shantie Jaghmohan-Changur, Cor Breukel, Hanne Meijers-Heijboer, Hans Morreau, Marjo van Puijenbroek, John Burn, Stephany Coronel, Yulia Kinarski, Ross Okimoto, Patrice Watson, Jane Lynch, Albert de la Chapelle, Henry Lynch Riccardo Fodde 1 Center for Human and Clinical Genetics, and 5 Department of Pathology, Leiden University Medical Center; 2 Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands; 3 Department of Preventive Medicine and Public Health, Creighton University, Omaha, NE; 4 Human Cancer Genetics Program, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA; 6 Department of Clinical Genetics, University of Newcastle, Newcastle upon Tyne, UK

PURPOSE:Immunohistochemistry (IHC) and microsatellite instability (MSI) analysis can be used to identify patients with a possible DNA mismatch repair defect [hereditary nonpolyposis colorectal carcinoma (HNPCC)]. The Bethesda criteria have been proposed to select families for determination of MSI. The aims of this study were to assess the yield of MSI analysis in families suspected for HNPCC, to compare the results of immunohistochemical staining and MSI analysis, and to assess the additional value of PMS2 staining.EXPERIMENTAL DESIGN:Clinical data and tumors were collected from 725 individuals from 631 families with suspected HNPCC. MSI analysis was performed using eight markers including the 5 National Cancer Institute markers. Four immunohistochemical staining antibodies were used (MLH1, MSH2, MSH6 and PMS2).RESULTS:A MSI-H (tumors with instability for >30% of the markers) phenotype in colorectal cancers (CRCs) was observed in 21-49% of families that met the various Bethesda criteria. In families with three cases of CRC diagnosed at age > 50 years, families with a solitary case of CRC diagnosed between ages 45 and 50 years, and families with one CRC case and a first-degree relative with a HNPCC-related cancer, one diagnosed between ages 45 and 50 years (all Bethesda-negative families), the yield of MSI-H was 10-26%. Immunohistochemical staining confirmed the MSI results in 93% of the cases. With IHC, adding PMS2 staining led to the identification of an additional 23% of subjects with an hMLH1 germ-line mutation (35 carriers were tested).CONCLUSIONS:The Bethesda guidelines for MSI analysis should include families with three or more cases of CRC diagnosed at age > 50 years. The age at diagnosis of CRC in the original guidelines should be raised to 50 years. Routine IHC diagnostics for HNPCC should include PMS2 staining.

s presented at the XVIth symposium of The Netherlands Foundation for the Detection of Hereditary Tumours, ‘New Developments in Hereditary Cancer’, 31 January 2003, Utrecht, The Netherlands Genomic deletions in PMS2: a cause of HNPCC? Y. Hendriks, H. van der Klift, H. Morreau, P. Franken, C. Tops, T. van Os, S. Jagmohan-Changur, H. Vasen, M. Breuning, A. Bröcker-Vriends, J. Wijnen and R. Fodde 1 Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands; 2 Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands; 3 Department of Clinical Genetics South-East Netherlands, Maastricht, The Netherlands; 4 Foundation for the Detection of Hereditary Tumours, Leiden, The Netherlands PMS2 is one of the mismatch repair (MMR) genes and is located on chromosome 7p22. PMS2 is a MutL homologue and is involved in repair of single-base mismatches and in repair of insertion-deletion loops. Mouse studies have shown that PMS2 null mice develop lymphomas and sarcomas and that the tumours show micro satellite instability (MSI). Nicolaides et al. described in 1994 a germline mutation in PMS2 in an individual from an HNPCC family. Other reported studies in HNPCC families and HNPCC suspect families have not revealed mutations in PMS2. However, mutations have been described in three Turcot families. Autosomal recessive inheritance was suggested in these families. We performed southern analysis of PMS2 in a large cohort of HNPCC families and HNPCC suspected families. All families were negative for mutations in MLH1, MSH2 and MSH6. We identified 4 large genomic deletions. One family fulfils the Amsterdam II criteria, the others don’t. Mutation analysis was performed in as many affected and at risk carriers as possible. MSI-analysis and immunohistochemistry (IHC) for the MMR proteins was performed in tumours from affected individuals. Three of the families are small and in the fourth segregation was not fully complete. Possibly phenocopies occurred in this family. MSI analysis and IHC in HNPCC related tumours from proven carriers showed an MSI-H phenotype and absent staining for PMS2, whereas MLH1, MSH2 and MSH6 stained positively. From our results it is probable that PMS2 is involved in HNPCC. Whether the deletions we found alone are sufficient to cause the phenotype is unclear. More research is required in larger groups of families to determine whether deletions in PMS2 are inherited in a autosomal fashion, whether presymptomatic testing can be offered and what the phenotype of deletions in PMS2 is. Immunohistochemical expression (IHC) and microsatellite instability (MSI) analysis in families with clustering of colorectal cancer M. van Puijenbroek, A. E. de Jong, C. Tops, J. Wijnen, M. Ausems, P. F. Franken, A. H. J. T. Bröcker-Vriends, R. Fodde, Th. van Os, H. MeijersHeijboer, H. F. A. Vasen and H. Morreau 1 Department of Pathology, 2 Department of Gastroenterology, 3 Center of Human and Clinical Genetics, Leiden Medical University Center, Leiden, The Netherlands; 4 The Netherlands Foundation for the Detection of Hereditary Tumours, Leiden, The Netherlands; 5 Department of Clinical Genetics, University Hospital Maastricht, Leiden, The Netherlands; 6 Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands Background: Hereditary nonpolyposis colorectal cancer (HNPCC) is caused by germline mutations in DNA-MMR genes. Due to the heterogeneity of the mutation spectrum of these genes, screening for mutations is both time-consuming and expensive. Immunohistochemical (IHC) and microsatellite instability (MSI) analysis can be used as pre-screening methods to identify patients with a possible MMR defect. In 1997 the Bethesda criteria have been proposed that can be used to select families for the determination of MSI. Aims: 1) to assess the yield of MSI-analysis and IHC-staining in families that meet the various Bethesda criteria and 2) to assess the additional value of PMS2 staining. Methods: Clinical data and tumours were collected from 517 individuals from families with clustering of colorectal cancer (CRC). The pedigrees were numbered according to the Bethesda criteria. MSIanalysis was performed using the five markers recommended by the 1997 workshop. IHC-staining was performed according to standard procedures for hMLH1, hMSH2, hMSH6 en PMS2. Results: 262 pedigrees scored Bethesda positive. A MSI-high/low phenotype in CRC tumors was observed in 21–50% of families that meet the various Bethesda 1

Mll (or 1 hour before and 5 hours during continuous nasogastric feeding.Patients were studied off acid suppressant therapy Results.Basal lower esophageal sphincter pressure was uniformly low (2.2mmHg + 0.4mmHg).Acid reflux occurred in 11 patients resulting m an acid exposure (pH<4) of 58%-+ 12% (x -+ SEM) preprandially and 63%+ 12% postprandially.Basal esophageal pH tended to be below pH 5 and if it dropped below pH 4 tended to remain so for prolonged periods of time.A total of 48 reflux events was identified, 34 by fall in pH, 8 by pH +impedance and 6 by impedance alone.Most (63%) occurred because of absent lower esoBhageal sphincter pressure alone, 35% were associated with straining/coughing.The mechanism underlying 1 reflux event could not be characterised.In addition, 15 slow drifts in eosphageal pH to below pH 4 occurred and accounted for 13% of acid exposure time.Conclusions.Gastroesophageal reflux in mechanically ventilated patients is due predominantly to very low or absent lower esophageal sphincter pressure, often with a superimposed cough or strain.Due to the low sphincter pressure we were not able to discern if TLESRs were implicated in the reflux events.These data suggest that drugs that increase basal LOS pressure may be useful to prevent reflux in ventilated patients.