Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fundic gland polyps (FGPs) are the most common gastric polyps. FGPs traditionally have been regarded as nondysplastic hamartomatous or hyperplastic lesions, but their pathogenesis remains unclear. We have recently shown that somatic adenomatous polyposis coli (APC) gene alterations are frequently present in FGPs associated with familial adenomatous polyposis (FAP), raising the possibility that mutations of the beta-catenin gene affecting the APC/beta-catenin pathway might be involved in the pathogenesis of sporadic FGPs. We analyzed somatic beta-catenin gene mutations in 57 sporadic FGPs from 40 patients without FAP and in 19 FGPs from 13 FAP patients. Direct DNA sequencing of exon 3 encompassing the glycogen synthase kinase-3beta phosphorylation region for beta-catenin was used with confirmation by HIN:fI restriction endonuclease digestion. The foveolar epithelium and dilated fundic glands of the polyps were separately microdissected and analyzed in 22 of 57 sporadic FGPs. Activating beta-catenin gene mutations were present in 91% (52 of 57) of sporadic FGPs. Both the foveolar epithelium and the dilated fundic gland epithelium comprising the polyps were shown to have the same somatic beta-catenin mutation in 21 of 22 (95%) sporadic FGPs. In contrast, beta-catenin gene mutations were not present in any of the 19 FAP-associated FGPs (P: < 0.000001). The high frequency of beta-catenin mutations in sporadic FGPs indicates that these lesions arise through activating mutations of the beta-catenin gene. Beta-catenin mutations in gastrointestinal tract polyps have previously only been demonstrated in a subset of adenomatous (dysplastic) or neoplastic polyps. Sporadic FGPs are therefore the only lesions of the gastrointestinal tract to demonstrate beta-catenin mutations while lacking dysplastic morphology.
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PMID:Sporadic fundic gland polyps: common gastric polyps arising through activating mutations in the beta-catenin gene. 1123 48

Sporadic fundic gland polyposis (SFGP) is defined as multiple fundic gland polyps in patients without familial adenomatous polyposis syndrome (FAP). Although little is known about the genetic changes in SFGP, mutations in the Wnt signaling pathway have been recently linked to fundic gland polyps in other settings: sporadic polyps are linked to activating beta-catenin mutations, whereas FAP-associated fundic gland polyps are caused by second somatic hits in the adenomatous polyposis coli gene. The relationship between SFGP, single sporadic fundic gland polyps, and FAP-associated polyps remains unclear, and SFGP remain poorly characterized at the clinical, histological, and molecular levels. A retrospective study was undertaken of eight patients with SFGP who had >/=10 polyps with at least five endoscopic biopsy specimens available for study. One additional patient with attenuated FAP who underwent partial gastrectomy was included as a control. The medical records and biopsy specimens were reviewed. Mutations of the beta-catenin gene were evaluated in each fundic gland as well as in control nonpolypoid tissue by direct sequencing of a mutational hot spot in exon 3 of the beta-catenin gene, which encodes the GSK-3beta phosphorylation sites, and a HinfI endonuclease digestion assay. The four men and four women in the study were an average of 57 years of age at biopsy. All patients were on acid-suppression therapy, 5/8 with proton-pump inhibitors (PPI) and 3/8 with Zantac. Sixty-two polyps were studied, and all were <10 mm, with most between 2 and 7 mm. The polyps were histologically identical to single sporadic fundic gland polyps. No dysplasia was seen. Forty-seven of 62 polyps (76%) had detectable beta-catenin mutations. Mutations were found in all eight of the patients. All were point mutations in codons 32, 33, 34, and 37 and are either phosphorylation sites or immediately adjacent to phosphorylation sites, findings identical to that seen in single sporadic fundic gland polyps. Each polyp had a single mutation, and each patient had more than one unique mutation (median = 4), indicating a multifocal origin for the polyps. No mutations were found in nonpolypoid control tissue and in polyps from the attenuated FAP patient. The patients with SFGP in this series were all between 40 and 70 years of age and had histories of acid-suppressive therapy. The fundic gland polyps were histologically and genetically identical to single sporadic fundic gland polyps and demonstrated frequent somatic activating mutations in exon 3 of the beta-catenin gene.
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PMID:Sporadic fundic gland polyposis: a clinical, histological, and molecular analysis. 1211 9