CTNNB1 mutations and ?-catenin protein accumulation in human hepatocellular carcinomas associated with high exposure to aflatoxin B1
| Autor: | Jack A. Taylor, Theodora R. Devereux, Zhen-Quan Zhang, Mimi C. Yu, Gordon P. Flake, Mariana C. Stern, Stephanie J. London |
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| Rok vydání: | 2001 |
| Předmět: |
Adult
Male Cancer Research Aflatoxin B1 Carcinoma Hepatocellular Beta-catenin DNA Mutational Analysis medicine.disease_cause medicine Humans Codon Molecular Biology Gene Polymorphism Single-Stranded Conformational beta Catenin Aged Mutation biology Point mutation Liver Neoplasms Wnt signaling pathway Infant Exons Middle Aged HCCS Genes p53 medicine.disease Immunohistochemistry Molecular biology digestive system diseases Cytoskeletal Proteins Hepatocellular carcinoma Trans-Activators biology.protein Phosphorylation Female Signal Transduction |
| Zdroj: | Molecular Carcinogenesis. 31:68-73 |
| ISSN: | 1098-2744 0899-1987 |
| Popis: | beta-Catenin plays a key role in the Wnt signaling pathway, and mutations of CTNNB1, the gene that encodes beta-catenin, have been identified in about one-fourth of human hepatocellular carcinomas from regions of low aflatoxin B1 exposure. In this study 62 hepatocellular carcinomas (HCCs) from people highly exposed to aflatoxin B1 in Guangxi, People's Republic of China, were laser-capture microdissected and examined for CTNNB1 mutations. In addition, 41 of the HCCs were evaluated for the presence of the beta-catenin protein by immunohistochemical methods. Twenty of the HCCs showed positive results for beta-catenin, with strong membrane staining, while adjacent non-neoplastic liver tissue lacked or showed only weak membrane staining. One HCC, in which a CTNNB1 mutation was not detected, showed nuclear staining for the beta-catenin protein. Mutations of CTNNB1 were identified in five HCCs. These consisted of four point mutations in the glycogen serine kinase-3beta phosphorylation region of codons 32-45 and one deletion of codons 32-38. These mutations were similar to those previously reported for human HCC, although at a lower frequency. A signature mutation profile associated with aflatoxin B1 exposure could not be identified. The immunohistochemical findings indicate a role for accumulation of beta-catenin and possibly increased Wnt signaling in aflatoxin B1-associated HCC. The low frequency of CTNNB1 mutations, however, suggests that mutation of another Wnt signaling component, such as the Wnt scaffolding protein axin or the adenomatous polyposis coli protein, both of which modulate beta-catenin stability, also may be involved in aflatoxin-associated HCC. Published 2001 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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