title: A case of myoepithelial carcinoma displaying biallelic inactivation of the tumour suppressor gene APC in a patient with familial adenomatous polyposis.
abstract: Familial adenomatous polyposis (FAP) is an autosomal dominant disorder caused by mutation of the APC gene. It is characterised by the appearance of hundreds to thousands of colorectal adenomas in adolescence and the subsequent development of colorectal cancer. Various extracolonic malignancies are associated with FAP, including desmoids and neoplasms of the stomach, duodenum, pancreas, liver, and brain. We present a family affected by FAP with an exon 14 APC mutation displaying two rare extracolonic lesions, a hepatoblastoma and a myoepithelial carcinoma. The hepatoblastoma was found in a male patient aged 2 years. The second lesion, a myoepithelial carcinoma of the right cheek, was found in a female patient aged 14 years. Inactivation of the normal APC allele was demonstrated in this lesion by loss of heterozygosity analysis, thus implicating APC in the initiation or progression of this neoplasm. This is the first reported case of this lesion in a family affected by FAP.
authors.affiliation: Conjoint Gastroenterology Laboratory, Clinical Research Centre, Royal Brisbane Hospital Research Foundation, Bancroft Centre, 300 Herston Road, Herston Q4029, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Young
authors.forename: M
authors.initials: M
authors.lastname: Barker
authors.forename: T
authors.initials: T
authors.lastname: Robertson
authors.forename: S
authors.initials: S
authors.lastname: Nasioulas
authors.forename: A
authors.initials: A
authors.lastname: Tannenberg
authors.forename: R L
authors.initials: RL
authors.lastname: Buttenshaw
authors.forename: N
authors.initials: N
authors.lastname: Knight
authors.forename: J R
authors.initials: JR
authors.lastname: Jass
authors.forename: B A
authors.initials: BA
authors.lastname: Leggett
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000235:genetics*; D000293:Adolescent; D002610:Cheek; D002675:Child, Preschool; D005260:Female; D017491:Genes, APC; D018197:Hepatoblastoma / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics; D019656:Loss of Heterozygosity; D008297:Male; D009208:Myoepithelioma / Q000235:genetics*; D012878:Skin Neoplasms / Q000235:genetics*