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31 result(s) for "Vasen, Hans FA"
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Evidence for genetic association between chromosome 1q loci and predisposition to colorectal neoplasia
Background: A substantial fraction of familial colorectal cancer (CRC) and polyposis heritability remains unexplained. This study aimed to identify predisposing loci in patients with these disorders. Methods: Homozygosity mapping was performed using 222 563 SNPs in 302 index patients with various colorectal neoplasms and 3367 controls. Linkage analysis, exome and whole-genome sequencing were performed in a family affected by microsatellite stable CRCs. Candidate variants were genotyped in 10 554 cases and 21 480 controls. Gene expression was assessed at the mRNA and protein level. Results: Homozygosity mapping revealed a disease-associated region at 1q32.3 which was part of the linkage region 1q32.2–42.2 identified in the CRC family. This includes a region previously associated with risk of CRC. Sequencing identified the p.Asp1432Glu variant in the MIA3 gene (known as TANGO1 or TANGO ) and 472 additional rare, shared variants within the linkage region. In both cases and controls the population frequency was 0.02% for this MIA3 variant. The MIA3 mutant allele showed predominant mRNA expression in normal, cancer and precancerous tissues. Furthermore, immunohistochemistry revealed increased expression of MIA3 in adenomatous tissues. Conclusions: Taken together, our two independent strategies associate genetic variations in chromosome 1q loci and predisposition to familial CRC and polyps, which warrants further investigation.
Small-bowel cancer in Lynch syndrome: is it time for surveillance?
Small-bowel cancer is part of the tumour spectrum of Lynch syndrome. Lynch syndrome, or hereditary non-polyposis colorectal cancer, is caused by germline mutations in one of the mismatch repair genes. Mutation carriers have an estimated lifetime risk for the development of small-bowel cancer of around 4%, corresponding to a relative risk of more than 100 compared with the general population. Patients with Lynch syndrome generally present with small-bowel cancer 10–20 years earlier than the general population, and small-bowel cancer might be the first clinical manifestation of Lynch syndrome. Tumours in patients with Lynch syndrome are evenly distributed within the small bowel. No specific risk factors, such as type of gene mutation, have been identified thus far. Screening for small-bowel cancer in Lynch syndrome has, until now, not been included in guidelines for surveillance, which might partly be due to the fact that, until recently, the possibilities for visualisation of the small bowel were limited. In view of the improved accessibility of the small bowel with the introduction of capsule endoscopy and double balloon enteroscopy, the question of whether patients should be screened for small-bowel neoplasia has regained attention. In this paper, we discuss the rationale for surveillance of small-bowel cancer in Lynch syndrome and highlight issues that need to be addressed in future studies before recommendations can be made.
Colorectal carcinomas in MUTYH-associated polyposis display histopathological similarities to microsatellite unstable carcinomas
Background MUTYH-associated polyposis (MAP) is a recessively inherited disorder which predisposes biallelic carriers for a high risk of polyposis and colorectal carcinoma (CRC). Since about one third of the biallelic MAP patients in population based CRC series has no adenomas, this study aimed to identify specific clinicopathological characteristics of MAP CRCs and compare these with reported data on sporadic and Lynch CRCs. Methods From 44 MAP patients who developed ≥ 1 CRCs, 42 of 58 tumours were analyzed histologically and 35 immunohistochemically for p53 and beta-catenin. Cell densities of CD3, CD8, CD57, and granzyme B positive lymphocytes were determined. KRAS2 , the mutation cluster region (MCR) of APC, p53 , and SMAD4 were analyzed for somatic mutations. Results MAP CRCs frequently localized to the proximal colon (69%, 40/58), were mucinous in 21% (9/42), and had a conspicuous Crohn's like infiltrate reaction in 33% (13/40); all of these parameters occurred at a higher rate than reported for sporadic CRCs. Tumour infiltrating lymphocytes (TILs) were also highly prevalent in MAP CRCs. Somatic APC MCR mutations occurred in 14% (5/36) while 64% (23/36) had KRAS2 mutations (22/23 c.34G>T). G>T tranversions were found in p53 and SMAD4 , although the relative frequency compared to other mutations was low. Conclusion MAP CRCs show some similarities to micro-satellite unstable cancers, with a preferential proximal location, a high rate of mucinous histotype and increased presence of TILs. These features should direct the practicing pathologist towards a MAP aetiology of CRC as an alternative for a mismatch repair deficient cause. High frequent G>T transversions in APC and KRAS2 (mutated in early tumour development) but not in P53 and SMAD4 (implicated in tumour progression) might indicate a predominant MUTYH effect in early carcinogenesis.
Twenty-five years of surveillance for familial and hereditary pancreatic ductal adenocarcinoma: Historical perspectives and introduction to the special issue
In the 1990s, as prevention became a central strategy in the battle against cancer and the molecular genetics revolution uncovered the genetic basis of numerous hereditary cancer syndromes, there were no options available for patients at increased risk of developing pancreatic cancer. When surveillance efforts for those at familial and hereditary risk of pancreatic cancer emerged in the late 1990s, it was uncertain if early detection was achievable.In this introduction to the special issue, we offer an overview of the history of surveillance for pancreatic cancer, including the first reports of familial pancreatic cancer in the medical literature, the initial results of surveillance in the United States and the initiation of surveillance programs for hereditary pancreatic cancer in the Netherlands.This special issue features a collection of 18 articles written by prominent experts in the field, focusing specifically on refining surveillance methodologies with the primary objective of improving care of high-risk individuals. Several reviews in this collection highlight improved survival rates associated with pancreas surveillance, underlying the potential of early detection and improved management in the continuing fight against pancreatic cancer.
Loss of ARID1A expression and its relationship with PI3K-Akt pathway alterations, TP53 and microsatellite instability in endometrial cancer
The switch/sucrose non-fermentable (SWI/SNF) subunit ARID1A ( AT-rich interactive domain 1A gene) has been recently postulated as a novel tumor suppressor of gynecologic cancer and one of the driver genes in endometrial carcinogenesis. However, specific relationships with established molecular alterations in endometrioid endometrial cancer (EEC) are currently unknown. We analyzed the expression of ARID1A in 146 endometrial cancers (130 EECs and 16 non-EECs) in relation to alterations in the PI3K-Akt pathway (PTEN expression/ KRAS / PIK3CA mutations), TP53 status (TP53 immunohistochemistry) and microsatellite instability. To discriminate between microsatellite instability due to somatic MLH1 promoter hypermethylation or germline mutations in one of the mismatch repair genes (Lynch syndrome), we included a ‘Lynch syndrome set’. This set included 21 cases with confirmed germline mutations and 15 cases that were suspected to have a germline mutation. Loss of ARID1A expression was exclusively found in EECs in 31% (40/130) of the EEC cases. No loss of expression of the other subunits of the SWI/SNF complex, SMARCD3 and SMARCB1, was detected. Alterations in the PI3K-Akt pathway were more frequent when ARID1A expression was lost. Loss of ARID1A and mutant-like TP53 expression was nearly mutually exclusive ( P =0.0004). In contrast to Lynch-associated tumors, a strong association between ARID1A loss and sporadic microsatellite instability was found. Only five cases (14%) of the ‘Lynch syndrome set’ as compared with 24 cases (75%, P <0.0001) of the sporadic microsatellite-unstable tumors showed loss of ARID1A . These observations suggest that ARID1A is a causative gene, instead of a target gene, of microsatellite instability by having a role in epigenetic silencing of the MLH1 gene in endometrial cancer.
Germline variants in POLE are associated with early onset mismatch repair deficient colorectal cancer
Germline variants affecting the exonuclease domains of POLE and POLD1 predispose to multiple colorectal adenomas and/or colorectal cancer (CRC). The aim of this study was to estimate the prevalence of previously described heterozygous germline variants POLE c.1270C>G, p.(Leu424Val) and POLD1 c.1433G>A, p.(Ser478Asn) in a Dutch series of unexplained familial, early onset CRC and polyposis index cases. We examined 1188 familial CRC and polyposis index patients for POLE p.(Leu424Val) and POLD1 p.(Ser478Asn) variants using competitive allele-specific PCR. In addition, protein expression of the POLE and DNA mismatch repair genes was studied by immunohistochemistry in tumours from POLE carriers. Somatic mutations were screened using semiconductor sequencing. We detected three index patients (0.25%) with a POLE p.(Leu424Val) variant. In one patient, the variant was found to be de-novo. Tumours from three patients from two families were microsatellite instable, and immunohistochemistry showed MSH6/MSH2 deficiency suggestive of Lynch syndrome. Somatic mutations but no germline MSH6 and MSH2 variants were subsequently found, and one tumour displayed a hypermutator phenotype. None of the 1188 patients carried the POLD1 p.(Ser478Asn) variant. POLE germline variant carriers are also associated with a microsatellite instable CRC. POLE DNA analysis now seems warranted in microsatellite instable CRC, especially in the absence of a causative DNA mismatch repair gene germline variant.
Extracolonic cancer risk in Dutch patients with APC (adenomatous polyposis coli)-associated polyposis
BackgroundScreening of patients with familial adenomatous polyposis (FAP) have led to a substantial reduction in mortality due to colorectal cancer (CRC). Recent guidelines suggest that surveillance of non-intestinal malignancies should also be considered in those patients. However, the value of these surveillance programmes is unknown. The aims of this study were (1) to assess the occurrence of extracolonic malignancies in a large series of adenomatous polyposis coli (APC) mutation carriers and (2) to evaluate the causes of death.MethodsAll APC mutation carriers were selected from the Dutch polyposis registry. Data on causes of death were collected. Pathology reports were retrieved from the Dutch Pathology Registry.ResultsA total of 85 extracolonic malignancies were diagnosed in 74 of 582 APC mutation carriers. Duodenal and skin cancers were the most prevalent cancers. Thyroid cancer was observed in only 1.5% of the cases. The main cause of death was cancer (59% of all deaths), with 42% due to CRC and 21% due to duodenal cancer. One patient died from thyroid cancer. The second and third most common causes of death were cardiovascular disease (13% of all deaths) and desmoid tumours (11% of all deaths), respectively.ConclusionExtending surveillance programmes to other cancers will not contribute significantly to the survival of patients with FAP.
Diet quality and colorectal tumor risk in persons with Lynch syndrome
•Both the Dutch Healthy Diet index 2015 (DHD15-index) and the Dietary Approaches to Stop Hypertension (DASH) score are inversely associated with colorectal cancer risk in the general population.•The DHD15-index and the DASH score were not associated with colorectal tumor risk in persons with Lynch Syndrome (LS).•Further studies should investigate the association between diet quality and mechanisms leading to the development of LS-associated tumors. Persons with Lynch syndrome (LS) have an increased risk of developing colorectal tumors (CRTs). Adherence to diet quality indices associated with colorectal cancer (CRC) risk in the general population has not been studied before in LS. Dietary habits of 490 participants with LS from a prospective cohort study was collected using a food frequency questionnaire. The Dutch Healthy Diet index 2015 (DHD15-index) and Dietary Approaches to Stop Hypertension (DASH) were used to score food-based diet quality. Diet quality scores were divided into tertiles where a higher tertile reflects a higher diet quality. Multivariable Cox proportional hazard regression models were used to estimate the association between the DHD15-index, DASH score and CRT risk. During a median follow-up time of 53.4 months, 210 participants (42.9%) developed CRTs. The DHD-index and DASH score were not associated with CRT risk; hazard ratios for highest vs. lowest tertile were 1.00 (95% Confidence Interval (CI): 0.67-1.48) and 1.11 (95% CI: 0.74-1.69), respectively. No linear trends across the DHD-index and DASH score tertiles were observed (P-trend = 0.97 and 0.83 respectively). In contrast to observations in the general population, no evidence for an association between the food-based DHD15-index or DASH score and CRT risk was observed in persons with LS. Further studies are needed investigating the association between diet quality and mechanisms leading to the development of LS-associated tumors.