Molecular genetic analysis of exons 1 to 6 of the APC gene in non-polyposis familial colorectal cancer |
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Authors: | Johanna A. Joyce Nicola J. Froggatt Rhodri Davies D. Gareth R. Evans Richard Trembath David E. Barton Eamonn R. Maher |
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Affiliation: | Cambridge University Department of Pathology;Molecular Genetics Laboratory, Addenbrooke's Hospital, Cambridge;Department of Medical Genetics, St Mary's Hospital, Manchester;Departments of Genetics and Medicine, University of Leicester, UK |
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Abstract: | Familial adenomatous polyposis coli is caused by constitutional mutations in the APC gene. The hallmark of familial adenomatous polyposis coli is the presence of numerous (>100) colorectal polyps, but mutations in the 5' end of the APC gene have been associated with familial colorectal cancer without florid polyposis. Although familial adenomatous polyposis coli accounts for only a minority of familial colorectal cancer cases, we hypothesised that APC mutations which were not associated with florid polyposis might make a significant contribution to nonpolyposis familial colorectal cancer. To investigate this possibility, we analysed 40 unrelated patients with familial colorectal cancer without classical familial adenomatous polyposis coli for mutations in exons 1 to 6 (codons 1 to 243) of the APC gene. No mutations were detected, but a C→T polymorphism at nucleotide 333 (Arg→Trp at codon 99) was identified. No 5' APC mutations were detected in two patients with desmoid tumours and a family history of colorectal cancer and polyps. We conclude that mutations in exons 1 to 6 of the APC gene are infrequent in patients with familial colorectal cancer who do not have many colorectal polyps. |
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Keywords: | APC gene coloractal cancer familial polyposis |
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