Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have studied three patients, one with extensive polyposis of the colon, who have constitutional interstitial deletions of the long arm of chromosome 5. High-resolution banding studies indicated that the deletion in the patient with polyposis spans the region 5q21-q22, which includes APC, a gene involved in familial adenomatous polyposis and sporadic colon cancer. Molecular analysis with probes for sequences flanking APC confirmed this conclusion. The deletions in the other two patients, who are too young to have developed polyposis, had breakpoints within this region, precluding the use of cytogenetic analysis alone in making definitive predictions about their risks. Molecular studies resolved the uncertainty; in situ and quantitative Southern hybridizations of four probes for polymorphic segments revealed that one of the patients has a deletion of MCC, a gene which is approximately 150 kb proximal to APC, and two flanking markers. He is at increased risk for polyposis, while the other patient is not. The physical descriptions of these patients, in conjunction with cases in the literature, begin to allow delineation of two distinct 5q-syndromes. These studies also provide precise physical mapping data for D5S71, D5S81, D5S84, and MCC on 5q.
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PMID:Phenotypic, cytogenetic, and molecular studies of three patients with constitutional deletions of chromosome 5 in the region of the gene for familial adenomatous polyposis. 832 66

Two yeast artificial chromosomes (YACs) spanning a total distance of 1.1 megabase pairs of DNA around the MCC (for mutated in colorectal carcinoma) and APC (for adenomatous polyposis coli) genes at 5q21 have been isolated and characterized. Starting from the MCC gene, a strategy was undertaken to identify constitutional submicroscopic deletions in familial adenomatous polyposis patients that might considerably narrow down the position of the APC gene. To this end, YACs identified by the MCC gene were screened across a chromosome 5-specific cosmid library to provide a source of DNA probes for genomic scanning. The cosmids isolated from these experiments were used to screen a panel of somatic cell hybrids containing chromosome 5 segregated from patients suspected to carry putative interstitial deletions. This screening approach led to the confirmation of a small heterozygous deletion in a polyposis patient that overlaps one of the two isolated YACs. This YAC has been shown to contain the entire APC gene, in addition to a significant portion of DNA flanking the 5' end of the gene, and should therefore prove a valuable resource for functional studies by transfer to colorectal tumor-derived cell lines.
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PMID:Yeast artificial chromosomes for the molecular analysis of the familial polyposis APC gene region. 132 52

The Singapore Polyposis Registry was established in 1989 in Singapore General Hospital. The aim is to provide a central registry service to all doctors in Singapore to facilitate in identification, surveillance and management of families and individuals at high risk of getting colorectal cancer from FAP (Familial Adenomatous Polyposis) and HNPCC (Hereditary Non-polyposis Colorectal Cancer). Both have an autosomal dominant inheritance that gives rise to colorectal cancer at any early age if untreated. They account for 5-6% of all colorectal cancers. Sixteen FAP families with 139 members have been evaluated. Fifty-eight members are affected and 81 are at risk or unaffected. Those who have been screened positive have a much lower risk of cancer (13%) compared with those who presented with the disease (89%) and death from colorectal cancer in the corresponding groups were nil and 58%. Eight HNPCC families with 36 affected and 170 at-risk members have been registered. Colonoscopic surveillance have just started: one case of Dukes' A cancer in a 26 year-old patient, and two cases with polyps have been diagnosed. Advances in molecular genetics and the identification of APC (Adenomatous Polyposis Coli) gene in the FAP locus of Chromosome 5 have made it possible to diagnose FAP genetically. This has important impact on management in terms of prenatal diagnosis and dietary and chemoprevention programmes in addition to surgical intervention.
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PMID:The Singapore Polyposis Registry. 132 51

Familial adenomatous polyposis is a rare disease inherited in a Mendelian dominant fashion. It is characterized by the occurrence of more than 100 adenomatous polyps in the large bowels of affected individuals. The genetic defect responsible for adenomatous polyposis resides at a locus called APC which has been localized to the long arm of human chromosome 5. In this study, the APC locus was mapped with respect to 11 markers known to map to this chromosomal segment. Linkage of APC to four of these markers had been previously reported. Three additional markers are shown here to be linked to APC. By multipoint analysis, the APC locus maps to an interval bounded by D5S49 and D5S58. The refined map of the APC locus and the new markers described here improve the informativeness and accuracy of the presymptomatic diagnosis of familial adenomatous polyposis.
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PMID:Genetic characterization of the APC locus involved in familial adenomatous polyposis. 164 39

Two independent study-groups, one in Britain and the other in the United States, were the first to report linkage between APC and a TaqI restriction fragment length polymorphism (RFLP) at D5S71 (probe C11p11) on chromosome 5q. They found no recombinants in about 50 informative meioses. The same TaqI RFLP was found to be uninformative for linkage in 15 Dutch polyposis families. The recently reported four base-pair deletion polymorphism (DEL1) at D5S71 has raised the polymorphism information content of this marker from 0.17 to 0.40 in the Dutch population. Seven of 20 polyposis families screened for the DEL1 as well as the TaqI polymorphism gave a combined peak lod score of 5.68 with no recombinants in 37 informative meioses. These data, together with those so far reported in the literature, raise the peak lod score to 17.09 at a recombination fraction of 0.05, the 95% upper confidence limit being 0.09. In combination with the use of another informative marker, D5S81 (probe YN5.48) closely mapping on the other side of APC, the presymptomatic diagnosis of the disease can be made with more than 99.9% certainty. It has to be stressed, however, that the the possible existence of more than one polyposis locus cannot, as yet, be excluded.
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PMID:A new deletion polymorphism at D5S71 raises the linkage information on adenomatous polyposis coli: implications for presymptomatic diagnosis. 167 49

A research project initiated in 1978 comprised establishment of a national polyposis registry, a genetic linkage study using classical and DNA markers, an in vitro study of fibroblasts for transformation parameters and chromosome instability, and a comparative study of DNA-RFLPs in cancer and constitutional tissue. The linkage study (to be reported elsewhere) confirmed the recently reported close linkage between the polyposis gene locus APC and D5S71. No in vitro test for the presence of the APC gene has been confirmed or revealed, but we detected increased chromosomal instability on a statistical basis and also recorded abnormal DNA-repair. As per 1. January 1988 the prevalence of adenomatosis of colon and rectum in Norway was 1/43,500. Among patients born in the period 1931-1950 the incidence at birth of developing the disease is 1/20,000 and the mutation rate is 1/72,000 per gamete per generation. In Norway new mutants in healthy families will comprise 1/3-1/2 of all new cases in the coming two decades, or one of 36,000 births.
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PMID:[The polyposis project]. 253 47

Focal neoplastic change occurs frequently within the colorectum. Yet, of the several hundreds of microadenomas that are likely to be present within an individual colorectum, only one or two will develop into a clinically diagnosable adenoma. In turn, only a fraction of adenomas will progress to malignancy. The risk that a particular microadenoma will end its natural history as a carcinoma varies according to clinical context. The risk is very low in familial adenomatous polyposis (FAP), but relatively high in hereditary non-polyposis colorectal cancer (HNPCC). This variation is governed by the timing and ordering of the underlying mutational events. In FAP, inactivation of the wild-type APC gene occurs early, whereas K-ras mutations are late events. The converse appears to apply in the case of sporadic adenomas. In flat adenomas, which are known to be relatively aggressive, K-ras mutations may not occur at all. In HNPCC, mutational events are accelerated as a result of defective DNA mismatch repair. The evolution of colorectal adenoma occurs through a variety of quite distinct genetic pathways.
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PMID:Colorectal adenoma progression and genetic change: is there a link? 754 18

Epidemiological studies and animal experiments show an association of dietary intake of fish oils and low incidence of several types of cancers. The active ingredients of fish oils appear to be polyunsaturated fatty acids of omega-3 type such as eicosapentaenoic acid and docosahexaenoic acid (DHA). We have investigated chemopreventive effects of DHA on mouse intestinal polyposis using adenomatous polyposis coli (Apc) gene knockout mice. Damage to the human APC gene is responsible for not only familial adenomatous polyposis but also many sporadic cancers of the entire digestive tract. Using homologous recombination in embryonic stem cells, we recently constructed gene knockout mice containing a truncation mutation in the Apc gene at codon 716 (Apc delta 716). The heterozygous mice developed numerous intestinal polyps, and all microadenomas dissected from the earliest polyps had already lost the wild-type allele, indicating the loss of heterozygosity [Oshima et al. (1995), Proc. Natl Acad. Sci. USA, 92, 4482-4486]. We fed Apc delta 716 heterozygotes with AIN-76A purified diet containing 3% DHA for 7 weeks, and scored the number and size of intestinal polyps. Average DHA intakes per day were 4.1 and 4.3 g/kg body wt for males and females, respectively. DHA-fed females had only 31% of polyps compared with the control females that developed about 220 polyps, whereas DHA-fed females showed no significant decrease in the polyp number. As for the polyp size, the proportion of larger polyps decreased more significantly in females than in males. This is the first demonstration that DHA inhibits intestinal polyposis induced by an Apc mutation at both its formation and growth.
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PMID:Effects of docosahexaenoic acid (DHA) on intestinal polyp development in Apc delta 716 knockout mice. 758 74

Genetic predispositions to colorectal cancer can schematically be divided in two categories depending on the presence or absence of a diffuse polyposis i.e.: a large number of adenomatous polyps in the colon and rectum of affected patients. These syndromes are referred as familial adenomatous polyposis coli and hereditary non polyposis colon cancer (HNPCC) respectively. The gene which when altered causes familial adenomatous polyposis coli is called APC and has been identified in 1991 but the function of its product remained elusive. Recent experimental data indicate that the APC protein can interact with catenins and tubulins, two groups of proteins known to be components of adherens junctions and cytoskeleton. Thus the APC protein may play a role in cell adhesion and in transduction of signal regulating the cell cycle. Of more immediate clinical interest is the observation that specific APC mutations appear to participate in the severity of the disease and determine the development of hypertrophy of the retinal pigment epithelium, a diagnostically important manifestation of the APC disease found in 70% of the patients. HNPCC syndromes have been recognized as being frequently associated with a defect in the DNA mismatch repair pathway. Furthermore, human genes, demonstrating homology with the bacterial DNA repair genes MutS and MutL, have been identified and shown to be altered in several HNPCC families. There are now indications that genotyping of tumor DNA at particular loci, termed microsatellite, may contribute in the identification of patients genetically predisposed to tumor development.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Genetic predispositions to colorectal cancer. 767 42

Mutations in the APC (adenomatous polyposis coli) gene appear to be responsible for not only familial adenomatous polyposis but also many sporadic cases of gastrointestinal cancers. Using homologous recombination in mouse embryonic stem cells, we constructed mice that contained a mutant gene encoding a product truncated at a 716 (Apc delta 716). Mendelian transmission of the gene caused most homozygous mice to die in utero before day 8 of gestation. The heterozygotes developed multiple polyps throughout the intestinal tract, mostly in the small intestine. The earliest polyps arose multifocally during the third week after birth, and new polyps continued to appear thereafter. Surprisingly, every nascent polyp consisted of a microadenoma covered with a layer of the normal villous epithelium. These microadenomas originated from single crypts by forming abnormal outpockets into the inner (lacteal) side of the neighboring villi. We carefully dissected such microadenomas from nascent polyps by peeling off the normal epithelium and determined their genotype by PCR: all microadenomas had already lost the wild-type Apc allele, whereas the mutant allele remained unchanged. These results indicate that loss of heterozygosity followed by formation of intravillous microadenomas is responsible for polyposis in Apc delta 716 intestinal mucosa. It is therefore unlikely that the truncated product interacts directly with the wild-type protein and causes the microadenomas by a dominant negative mechanism.
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PMID:Loss of Apc heterozygosity and abnormal tissue building in nascent intestinal polyps in mice carrying a truncated Apc gene. 775 29


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