Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MUTYH adenomatous polyposis (MAP) can mimic both the familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC) phenotypes. As a result of MAP's phenotypic overlap with FAP, some DNA diagnostic laboratories perform MUTYH testing in conjunction with APC testing in patients with suspected FAP or attenuated FAP (AFAP). In addition to testing FAP/AFAP samples for MUTYH mutations, we were interested whether there would also be value in testing samples referred for HNPCC testing. To determine this, we tested a consecutive series of 229 samples referred for HNPCC testing for the two most common MUTYH mutations in the Caucasian population. To enrich our study population with MAP cases, we only included samples from patients with early onset colorectal cancer (CRC diagnosed <50 years old) in whom HNPCC had been excluded by microsatellite instability testing (microsatellite stable or low microsatellite instability). Four biallelic (2%) and six monoallelic (3%) MUTYH mutation carriers were identified. No clinical factors predicted MUTYH mutation status. Specifically, a family history of vertical transmission of CRC or having few polyps (<15) did not rule out the possibility of biallelic MUTYH mutations. Thus, MUTYH mutation testing may be a reasonable cascade test in early onset CRC found to have proficient DNA mismatch repair, regardless of pattern of family history or number of polyps.
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PMID:The value of MUTYH testing in patients with early onset microsatellite stable colorectal cancer referred for hereditary nonpolyposis colon cancer syndrome testing. 1829 51

MUTYH-associated polyposis (MAP) is an autosomal recessive condition predisposing to colorectal cancer, caused by constitutional biallelic mutations in the base excision repair (BER) gene MUTYH. Colorectal tumours from MAP patients display an excess of somatic G>T mutations in the APC and KRAS genes due to defective BER function. To date, few extracolonic manifestations have been observed in MAP patients, and the clinical spectrum of this condition is not yet fully established. Recently, one patient with a diagnosis of endometrial cancer and biallelic MUTYH mutations has been described. We here report on two additional unrelated MAP patients with biallelic MUTYH germline mutations who developed endometrioid endometrial carcinoma. The endometrial tumours were evaluated for PTEN, PIK3CA, KRAS, BRAF and CTNNB1 mutations. A G>T transversion at codon 12 of the KRAS gene was observed in one tumour. A single 1bp frameshift deletion of PTEN was observed in the same sample. Overall, these findings suggest that endometrial carcinoma is a phenotypic manifestations of MAP and that inefficient repair of oxidative damage can be involved in its pathogenesis.
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PMID:Endometrial cancer and somatic G>T KRAS transversion in patients with constitutional MUTYH biallelic mutations. 1898 Aug

MUTYH-associated polyposis (MAP) is an autosomal recessive disorder characterised by adenomatous polyps of the colorectum and a very high risk of colorectal cancer. It appears to be at least as prevalent as autosomal dominant familial adenomatous polyposis (that is caused by truncating mutations in the APC gene) with which it shares important gastroenterological features. It was first recognised as recently as 2002 and its full phenotype and natural history are still being characterised. Key extracolonic manifestations include a predisposition to duodenal adenomas and cancer and a modest increase in risk for several extraintestinal tumours. Testing for mutations in the MUTYH gene is indicated in patients who have multiple colorectal adenomas or a family history suggestive of autosomal recessive colorectal cancer and for the siblings and spouses of patients with MAP in order to inform surveillance and treatment for patients and their families.
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PMID:MUTYH-associated polyposis. 1941 47

The concept of the adenoma-carcinoma sequence, as first espoused by Morson et al. whereby the development of colorectal cancer is dependent on a stepwise progression from adenomatous polyp to carcinoma is well documented. Initial studies of the genetics of inherited colorectal cancer susceptibility concentrated on the inherited colorectal cancer syndromes, such as Familial Adenomatous Polyposis (FAP) and Lynch Syndrome (also known as HNPCC). These syndromes, whilst easily characterisable, have a well understood sequence of genetic mutations that predispose the sufferer to developing colorectal cancer, initiated for example in FAP by the loss of the second, normal allelle of the tumour supressor APC gene. Later research has identified other inherited variants such as MUTYH (MYH) polyposis and Hyperplastic Polyposis Syndrome. Recent research has concentrated on the pathways by which colorectal adenomatous polyps not due to one of these known inherited susceptibilities undergo malignant transformation, and determination of the types of polyps most likely to do so. Also, why do individuals in certain families have a predisposition to colorectal cancer. In this article, we will discuss briefly the current state of knowledge of the genomics of the classical inherited colorectal cancer syndromes. We will also discuss in detail the genetic changes in polyps that undergo malignant transformation as well as current knowledge with regards to the epigenomic changes found in colorectal polyps.
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PMID:The genomics of colorectal cancer: state of the art. 1942 78

MUTYH Associated Polyposis (MAP), a Polyposis predisposition caused by biallelic mutations in the Base Excision Repair (BER) gene MUTYH, confers a marked risk of colorectal cancer (CRC). The MAP phenotype is difficult to distinguish from other hereditary CRC syndromes. Especially from Familial Adenomatous Polyposis (FAP) and to a lesser extend Lynch Syndrome, which are caused by germline mutations in the APC and Mismatch Repair (MMR) genes, respectively.Here we review research findings regarding MUTYH interactions, genotypic and phenotypic characteristics of MAP, as well as surveillance and treatment of the disease. The applied papers, published between 1/1 2002- 1/2 2008, were found through PubMed.The exact role of MUTYH in CRC tumorgenesis is still uncertain, although MAP tumors show distinct molecular features, including somatic G:C>T:A transversions in the APC gene. Furthermore, cooperation between the BER and the MMR systems exists, as MUTYH interacts with MMR gene-products. Possibly, monoallelic defects in both pathways are of significance to CRC development.Specific MUTYH variants are found to be characteristic in distinct ethnic populations, which could facilitate future genetic screening. Knowledge concerning functional consequences of many MUTYH germline mutations remains sparse. Most thoroughly investigated are the two most common MUTYH variants, Y179C and G396D, both generating dysfunctional gene products.PHENOTYPIC FEATURES OF MAP INCLUDE: development of 10-100 colorectal adenomas, debuting at 46-47 years, often CRC at time of clinical diagnosis, and in some, development of extracolonic manifestations.
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PMID:MUTYH Associated Polyposis (MAP). 1950 31

Patients presenting familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP) or multiple colorectal adenomas (MCRAs) phenotype are clinically difficult to distinguish. We aimed to genetically characterize 107 clinically well-characterized patients with FAP-like phenotype, and stratified according to the recent guidelines for the clinical management of FAP: FAP, AFAP, MCRA (10-99 colorectal adenomas) without family history of colorectal cancer or few adenomas (FH), MCRA (10-99) with FH, MCRA (3-9) with FH. Overall, APC or MUTYH mutations were detected in 42/48 (88%), 14/20 (70%) and 10/38 (26%) of FAP, AFAP and MCRA patients, respectively. APC and MUTYH mutations accounted for 81% and 7% of FAP patients and for 30% and 40% of AFAP patients, respectively. Notably, MCRA patients did not present APC mutations. In 26% of these patients, an MUTYH mutation was identified and the detection rate increased with the number of adenomas, irrespectively of family history, being significantly higher in MCRA patients presenting more than 30 adenomas [7/12 (58%) vs 2/14 (14%), p = 0.023]. We validate the recently proposed guidelines in our patient's cohort and show that APC or MUTYH germline defects are responsible for the majority of clinically well-characterized patients with FAP and AFAP phenotype, and patients with more than 30 colorectal adenomas. The different mutation frequencies according to family history and to the number of adenomas underscore the importance of an adequate familial characterization, both clinically and by colonoscopy, in the management of FAP-like phenotypes. The phenotypes of the mutation-negative patients suggest distinct etiologies in these cases.
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PMID:APC or MUTYH mutations account for the majority of clinically well-characterized families with FAP and AFAP phenotype and patients with more than 30 adenomas. 1979 53

Familial adenomatous polyposis (FAP) is characterized by the development of many tens to thousands of adenomas in the rectum and colon during the second decade of life. FAP has an incidence at birth of about 1/8,300, it manifests equally in both sexes, and accounts for less than 1% of colorectal cancer (CRC) cases. In the European Union, prevalence has been estimated at 1/11,300-37,600. Most patients are asymptomatic for years until the adenomas are large and numerous, and cause rectal bleeding or even anemia, or cancer develops. Generally, cancers start to develop a decade after the appearance of the polyps. Nonspecific symptoms may include constipation or diarrhea, abdominal pain, palpable abdominal masses and weight loss. FAP may present with some extraintestinal manifestations such as osteomas, dental abnormalities (unerupted teeth, congenital absence of one or more teeth, supernumerary teeth, dentigerous cysts and odontomas), congenital hypertrophy of the retinal pigment epithelium (CHRPE), desmoid tumors, and extracolonic cancers (thyroid, liver, bile ducts and central nervous system). A less aggressive variant of FAP, attenuated FAP (AFAP), is characterized by fewer colorectal adenomatous polyps (usually 10 to 100), later age of adenoma appearance and a lower cancer risk. Some lesions (skull and mandible osteomas, dental abnormalities, and fibromas on the scalp, shoulders, arms and back) are indicative of the Gardner variant of FAP. Classic FAP is inherited in an autosomal dominant manner and results from a germline mutation in the adenomatous polyposis (APC) gene. Most patients (~70%) have a family history of colorectal polyps and cancer. In a subset of individuals, a MUTYH mutation causes a recessively inherited polyposis condition, MUTYH-associated polyposis (MAP), which is characterized by a slightly increased risk of developing CRC and polyps/adenomas in both the upper and lower gastrointestinal tract. Diagnosis is based on a suggestive family history, clinical findings, and large bowel endoscopy or full colonoscopy. Whenever possible, the clinical diagnosis should be confirmed by genetic testing. When the APC mutation in the family has been identified, genetic testing of all first-degree relatives should be performed. Presymptomatic and prenatal (amniocentesis and chorionic villous sampling), and even preimplantation genetic testing is possible. Referral to a geneticist or genetic counselor is mandatory. Differential diagnoses include other disorders causing multiple polyps (such as Peutz-Jeghers syndrome, familial juvenile polyps or hyperplastic polyposis, hereditary mixed polyposis syndromes, and Lynch syndrome). Cancer prevention and maintaining a good quality of life are the main goals of management and regular and systematic follow-up and supportive care should be offered to all patients. By the late teens or early twenties, colorectal cancer prophylactic surgery is advocated. The recommended alternatives are total proctocolectomy and ileoanal pouch or ileorectal anastomosis for AFAP. Duodenal cancer and desmoids are the two main causes of mortality after total colectomy, they need to be identified early and treated. Upper endoscopy is necessary for surveillance to reduce the risk of ampullary and duodenal cancer. Patients with progressive tumors and unresectable disease may respond or stabilize with a combination of cytotoxic chemotherapy and surgery (when possible to perform). Adjunctive therapy with celecoxib has been approved by the US Food and Drug Administration and the European Medicines Agency in patients with FAP. Individuals with FAP carry a 100% risk of CRC; however, this risk is reduced significantly when patients enter a screening-treatment program.
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PMID:Familial adenomatous polyposis. 1982 6

There are two major hereditary colorectal cancer syndromes: Adenomatous Polyposis, secondary to APC germline alterations (FAP, Familial Adenomatous Polyposis) or secondary to MUTYH germline alterations (MAP, MUTYH associated Polyposis), and Lynch syndrome, associated with germline mutations in mismatch repair genes (MLH1, MSH2, MSH6 and PMS2). The elucidation of their genetic basis has depicted an increasingly complex picture that has lead to the implementation of complex diagnostic algorithms that include both tumor profiling and germline analyses. A variety of techniques at the DNA, RNA and protein level are used to screen for molecular alterations both in tumor biopsies (microsatellite instability analysis, mismatch repair protein immunohistochemistry, BRAF-Val600Glu detection and MLH1 promoter hypermethylation analysis) and in the germline (point mutation screening, copy number assessment). Also functional tests are more often used to characterize variants of unknown significance. Methodological issues associated with the techniques analyzed, as well as the algorithms used, are discussed.
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PMID:Detection of genetic alterations in hereditary colorectal cancer screening. 1993 46

The genetic susceptibility to colorectal cancer (CRC) has been estimated to be around 35% and yet high-penetrance germline mutations found so far explain less than 5% of all cases. Much of the remaining variations could be due to the co-inheritance of multiple low penetrant variants. The identification of all the susceptibility alleles could have public health relevance in the near future. To test the hypothesis that what are considered polymorphisms in human CRC genes could constitute low-risk alleles, we selected eight common SNPs for a pilot association study in 1785 cases and 1722 controls. One SNP, rs3219489:G>C (MUTYH Q324H) seemed to confer an increased risk of rectal cancer in homozygous status (OR=1.52; CI=1.06-2.17). When the analysis was restricted to our 'super-controls', healthy individuals with no family history for cancer, also rs1799977:A>G (MLH1 I219V) was associated with an increased risk in both colon and rectum patients with an odds ratio of 1.28 (CI=1.02-1.60) and 1.34 (CI=1.05-1.72), respectively (under the dominant model); while 2 SNPs, rs1800932:A>G (MSH6 P92P) and rs459552:T>A (APC D1822V) seemed to confer a protective effect. The latter, in particular showed an odds ratio of 0.76 (CI=0.60-0.97) among colon patients and 0.73 (CI=0.56-0.95) among rectal patients. In conclusion, our study suggests that common variants in human CRC genes could constitute low-risk alleles.
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PMID:Common variants in human CRC genes as low-risk alleles. 2014 37

The autosomal-dominant precancerous condition familial adenomatous polyposis (FAP) is caused by germline mutations in the tumour suppressor gene APC. Consistent correlations between the site of mutations in the gene and clinical phenotype have been published for different patient groups. We report our experiences of APC mutation analysis and genotype-phenotype correlations in 1166 unrelated polyposis families and discuss our results in the light of literature data. We show that the mutation detection rates largely depend on the family history and clinical course of the disease. We present a list of 315 different point mutations and 37 large deletions detected in 634 of the 1166 index patients. Our results confirm previously published genotype-phenotype correlations with respect to the colorectal phenotype and extracolonic manifestations. However, 'exceptions to the rule' are also observed, and possible explanations for this are discussed. The discovery of autosomal-recessive MUTYH-associated polyposis (MAP) as a differential diagnosis to FAP implies that some results have to be reinterpreted and surveillance guidelines in the families have to be reevaluated.
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PMID:Familial adenomatous polyposis: experience from a study of 1164 unrelated german polyposis patients. 2022 39


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