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1/6. Familial adenomatous polyposis: a case report and histologic mucin study.

    adenocarcinoma arising at an ileostomy is uncommon, and only 29 cases have been reported in the literature. The case of a 54-year-old man who developed an adenocarcinoma at a Brooke ileostomy is reported. The ileostomy had been fashioned 21 years earlier after proctocolectomy for familial adenomatous polyposis (FAP). A wide local excision of the stoma was performed, and a new Brooke ileostomy was fashioned on the opposite side of the abdomen. Histopathologic examination revealed a well-differentiated adenocarcinoma with early invasion of the submucosa. On hematoxylin and eosin staining, the ileal mucosa adjacent to the tumor showed signs of colonic metaplasia, including loss of villous architecture and a reduced number of paneth cells. Mucin staining using the high iron diamine-alcian blue stain demonstrated a mixture of sulfomucin and sialomucin in the ileal mucosa near the tumor, confirming colonic metaplasia. ileostomy site carcinogenesis can be attributed to both the colonic metaplasia and the inherent nature of FAP or ulcerative colitis (UC), where colonic mucosa is susceptible to adenoma formation or dysplasia. Longstanding ileostomies in patients with FAP or UC should be followed to exclude the development of adenoma, dysplasia, or cancer.
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keywords = carcinogenesis
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2/6. Hepatocellular adenoma displaying a HNF1alpha inactivation in a patient with familial adenomatous polyposis coli.

    patients with familial adenomatous polyposis coli (FAP) may rarely develop hepatocellular adenoma. Here we report the case of a 37-year-old FAP woman presenting a hepatocellular adenoma after oestroprogestative oral contraception use. In this steatotic adenoma, we identified an inactivating biallelic mutation of HNF1alpha. In addition to the known germline APC mutation Q1062fs, we did not find an inactivation of the second APC allele nor an activation of the beta-catenin target genes GLUL and GPR49. Our findings contrast with two hepatocellular adenoma cases related to FAP, for which a biallelic inactivation of the APC gene was previously described. Altogether, these results suggest that benign hepatocellular carcinogenesis may be dependent on or independent of the Wnt/beta-catenin pathway in patients with FAP.
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keywords = carcinogenesis
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3/6. The usefulness of severe combined immunodeficiency (SCID) mice to study human carcinogenesis.

    In the present study, we engrafted normal colonic epithelial and histologically diagnosed colonic adenomas from a familial adenomatous polyposis (FAP) patient into severe combined immunodeficient (SCID) mice and subsequently examined them histologically and molecular biologically. Successful engraftment and metastasis was observed. The facts that human normal colonic epithelium and adenomatous polyps can take in SCID mice indicates the possibility that this human SCID mouse system will be useful for investigating the dynamics of human carcinogenesis in various tissues.
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ranking = 5
keywords = carcinogenesis
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4/6. K-ras mutation in a tubular adenoma originating at an ileostomy in a familial adenomatous polyposis patient.

    Genetic alterations in a tubular adenoma with severe dysplasia arising in a Brooke ileostomy of a familial adenomatous polyposis patient were analyzed. Clinical and morphological characteristics suggest that ileal mucosa progressed to colonic metaplasia and then to dysplastic adenoma. Such changes at ileostomy sites are rare, and little is known about the associated genetic alterations. To determine whether metaplastic epithelium progression to adenoma in the ileum is subject to the same mutations identified in colon carcinogenesis, we evaluated somatic genetic alterations associated with sporadic colorectal cancer development. Sequences examined included mutation cluster regions of the p53 tumor suppressor gene and the k-ras oncogene. Using polymerase chain reaction and dna sequencing, we identified a point mutation at codon 12 of the K-ras oncogene. To our knowledge, this is the first report of a ras mutation occurring in a tumor originating from ileal mucosa.
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keywords = carcinogenesis
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5/6. Triple primary malignant neoplasms including a malignant brain tumor: report of two cases and review of the literature.

    BACKGROUND: Two rare cases of triple primary malignant neoplasms (PMN), including malignant brain tumors, which were glioblastoma multiformes, are described. methods: The clinical characteristics and underlying genetic alterations in triple or more PMN, including malignant brain tumors are discussed with intensive review of the literature. RESULTS: The first patient, a 77-year-old male, suffered metachronously from tubular adenocarcinoma of the stomach, transitional cell carcinoma of the bladder, and glioblastoma in the brain. This glioblastoma had loss of heterozygosity in exons 7-8 in p53 gene. The second patient, a 68-year-old male, developed papillary adenocarcinoma of the lung, adenocarcinoma of the rectum, and glioblastoma in the brain during a period of 7 years. In 42 such cases described in the literature, age distribution demonstrated two characteristic peaks, one in the third decade and the other over 50 years of age. The younger group consisted mainly of Turcot's syndrome, and of a case of Li-Fraumeni familial cancer syndrome. On the other hand, neither of these hereditary cancer syndromes were contained in the elder group. Regarding the site of PMN, colorectal cancers were associated most frequently with malignant brain tumors, followed by stomach cancers, and thyroid cancers. Malignant brain tumors, mostly glioblastoma multiforme, tend to occur as the last tumor of triple or more PMN. CONCLUSIONS: These results suggest that genetic background might play an important role in tumorigenesis of PMN in the younger group, whereas epigenetic factors would be more important in the older group. Characteristic organ association and factors influencing carcinogenesis, such as aging, environmental carcinogens, and underlying genetic alterations in these tumors are further discussed.
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keywords = carcinogenesis
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6/6. Drastic genetic instability of tumors and normal tissues in Turcot syndrome.

    Turcot syndrome is characterized by an association of malignant brain tumors and colon cancer developing in the patient's teens. Since the mechanism of carcinogenesis in Turcot syndrome is still unclear, we analysed genetic changes in tumors from a Turcot patient with no family history of the condition. All tumors, including one astrocytoma, three colon carcinomas, and two colon adenomas, exhibited severe replication error (RER), and all colon tumors showed somatic mutations at repeated regions of TGFbetaRII, E2F-4, hMSH3, and/or hMSH6 genes. Somatic APC mutations were detected in three of three colon carcinomas, and somatic p53 mutations were detected in the astrocytoma and two of three colon carcinomas, both of which showed two mutations without allele loss. We also found that normal colon mucosa, normal skin fibroblasts and normal brain tissue from this patient showed respective high frequencies of RER, in contrast to usual HNPCC patients in which RER was very rare in normal tissues. These results suggest that extreme dna instability in normal tissues causes the early development of multiple cancer in Turcot syndrome. A missense mutation (GAG to AAG) at codon 705 of hPMS2 gene was detected in one allele of this patient, which was inherited from his mother without tumors. Additional unknown germline mutation may contribute to the genetic instability in normal tissues.
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ranking = 1
keywords = carcinogenesis
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