Topic
Familial adenomatous polyposis
About: Familial adenomatous polyposis is a research topic. Over the lifetime, 4770 publications have been published within this topic receiving 190955 citations. The topic is also known as: adenomatous polyposis of the colon & Familial polyposis coli.
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TL;DR: It is found that ras-gene mutations occurred in 58 percent of adenomas larger than 1 cm and in 47 percent of carcinomas, which are consistent with a model of colorectal tumorigenesis in which the steps required for the development of cancer often involve the mutational activation of an oncogene coupled with the loss of several genes that normally suppress tumors.
Abstract: Because most colorectal carcinomas appear to arise from adenomas, studies of different stages of colorectal neoplasia may shed light on the genetic alterations involved in tumor progression. We looked for four genetic alterations (ras-gene mutations and allelic deletions of chromosomes 5, 17, and 18) in 172 colorectal-tumor specimens representing various stages of neoplastic development. The specimens consisted of 40 predominantly early-stage adenomas from 7 patients with familial adenomatous polyposis, 40 adenomas (19 without associated foci of carcinoma and 21 with such foci) from 33 patients without familial polyposis, and 92 carcinomas resected from 89 patients. We found that ras-gene mutations occurred in 58 percent of adenomas larger than 1 cm and in 47 percent of carcinomas. However, ras mutations were found in only 9 percent of adenomas under 1 cm in size. Sequences on chromosome 5 that are linked to the gene for familial adenomatous polyposis were not lost in adenomas from the patients with polyposis but were lost in 29 to 35 percent of adenomas and carcinomas, respectively, from other patients. A specific region of chromosome 18 was deleted frequently in carcinomas (73 percent) and in advanced adenomas (47 percent) but only occasionally in earlier-stage adenomas (11 to 13 percent). Chromosome 17p sequences were usually lost only in carcinomas (75 percent). The four molecular alterations accumulated in a fashion that paralleled the clinical progression of tumors. These results are consistent with a model of colorectal tumorigenesis in which the steps required for the development of cancer often involve the mutational activation of an oncogene coupled with the loss of several genes that normally suppress tumorigenesis.
6,309 citations
TL;DR: DNA from 61 unrelated patients with adenomatous polyposis coli (APC) was examined for mutations in three genes located within a 100 kb region deleted in two of the patients, and data have established that DP2.5 is the APC gene.
2,754 citations
TL;DR: In patients with familial adenomatous polyposis, six months of twice-daily treatment with 400 mg of celecoxib, a cyclooxygenase-2 inhibitor, leads to a significant reduction in the number of colorectal polyps.
Abstract: Background Patients with familial adenomatous polyposis have a nearly 100 percent risk of colorectal cancer. In this disease, the chemopreventive effects of nonsteroidal antiinflammatory drugs may be related to their inhibition of cyclooxygenase-2. Methods We studied the effect of celecoxib, a selective cyclooxygenase-2 inhibitor, on colorectal polyps in patients with familial adenomatous polyposis. In a double-blind, placebo-controlled study, we randomly assigned 77 patients to treatment with celecoxib (100 or 400 mg twice daily) or placebo for six months. Patients underwent endoscopy at the beginning and end of the study. We determined the number and size of polyps from photographs and videotapes; the response to treatment was expressed as the mean percent change from base line. Results At base line, the mean (±SD) number of polyps in focal areas where polyps were counted was 15.5±13.4 in the 15 patients assigned to placebo, 11.5±8.5 in the 32 patients assigned to 100 mg of celecoxib twice a day, and 12...
2,463 citations
TL;DR: Results provide direct genetic evidence that COX-2 plays a key role in tumorigenesis and indicate that COx-2-selective inhibitors can be a novel class of therapeutic agents for colorectal polyposis and cancer.
2,446 citations
TL;DR: The APC gene was identified in a contig initiated from the MCC gene and was found to encode an unusually large protein, and these two closely spaced genes encode proteins predicted to contain coiled-coil regions, which were also expressed in a wide variety of tissues.
Abstract: Recent studies suggest that one or more genes on chromosome 5q21 are important for the development of colorectal cancers, particularly those associated with familial adenomatous polyposis (FAP). To facilitate the identification of genes from this locus, a portion of the region that is tightly linked to FAP was cloned. Six contiguous stretches of sequence (contigs) containing approximately 5.5 Mb of DNA were isolated. Subclones from these contigs were used to identify and position six genes, all of which were expressed in normal colonic mucosa. Two of these genes (APC and MCC) are likely to contribute to colorectal tumorigenesis. The MCC gene had previously been identified by virtue of its mutation in human colorectal tumors. The APC gene was identified in a contig initiated from the MCC gene and was found to encode an unusually large protein. These two closely spaced genes encode proteins predicted to contain coiled-coil regions. Both genes were also expressed in a wide variety of tissues. Further studies of MCC and APC and their potential interaction should prove useful for understanding colorectal neoplasia.
2,364 citations