Hepatoblastoma and APC Gene Mutation in Familial Adenomatous Polyposis Gut: First Published As 10.1136/Gut.39.6.867 on 1 December 1996

Hepatoblastoma and APC Gene Mutation in Familial Adenomatous Polyposis Gut: First Published As 10.1136/Gut.39.6.867 on 1 December 1996

Gut 1996; 39: 867-869 867 Hepatoblastoma and APC gene mutation in familial adenomatous polyposis Gut: first published as 10.1136/gut.39.6.867 on 1 December 1996. Downloaded from F M Giardiello, G M Petersen, J D Brensinger, M C Luce, M C Cayouette, J Bacon, S V Booker, S R Hamilton Abstract tumours; and extracolonic cancers of the Background-Hepatoblastoma is a rare, thyroid, duodenum, pancreas, liver, and rapidly progressive, usually fatal child- brain.1-4 hood malignancy, which if confined to the Hepatoblastoma is a rare malignant liver can be cured by radical surgical embryonal tumour of the liver, which occurs in resection. An association between hepato- infancy and childhood. An association between blastoma and familial adenomatous hepatoblastoma and familial adenomatous polyposis (FAP), which is due to germline polyposis was first described by Kingston et al mutation of the APC (adenomatous in 1982,6 and since then over 30 additional polyposis coli) gene, has been confirmed, cases have been reported.7-15 Moreover, a but correlation with site of APC mutation pronounced increased relative risk of hepato- has not been studied. blastoma in patients affected with FAP and Aim-To analyse the APC mutational their first degree relatives has been found spectrum in FAP families with hepato- (relative risk 847, 95% confidence limits 230 blastoma as a possible basis to select and 2168).16 kindreds for surveillance. FAP is caused by germline mutations of the Patients-Eight patients with hepato- APC (adenomatous polyposis coli) gene blastoma in seven FAP kindreds were located on the long arm of chromosome 5 in compared with 97 families with identified band q2 1.17-'20The APC gene has 15 exons and APC gene mutation in a large Registry. encodes a predicted gene product of 2843 Methods-APC gene mutation was evalu- amino acids with a molecular weight of about ated by RNase protection assay or in vitro 300 000 Daltons. Mutations of the APC gene synthesis protein assay. The x2 test and have been reported in over 170 FAP correlation were used for data analysis. patients.'7 19-32 Mutations are located primarily http://gut.bmj.com/ Results-APC gene mutation was identi- in the 5' half but extend throughout the length fied in all seven FAP kindreds in which an of the APC gene, and most lead to truncation at risk member developed hepato- of the APC gene product. blastoma. A male predominance was The correlation of extracolonic phenotype noted (six of eight), similar to literature with specific APC mutations has not been Departments of Medicine, Pathology, cases (18 of 25, p<0*01. Mutations were evaluated in detail. Two studies have suggested and Oncology Center, restricted to codons 141 to 1230, but no that the occurrence ofpigmented ocular fundic on October 2, 2021 by guest. Protected copyright. The Johns Hopkins significant difference in site of mutation lesions (congenital hypertrophy of the retinal University School of Medicine between pedigrees with and without pigmented epithelium) is restricted to APC F M Giardiello hepatoblastoma was identified. mutation in codons 463 to 1387.33 34 One G M Petersen Conclusions-Hepatoblastoma occurs pri- investigation found that patients with J D Brensinger J Bacon marily in boys in FAP kindreds and is mutations between codons 1445 and 1578 S V Booker associated with germline APC mutation in frequently developed desmoid tumours.34 Also, S R Hamilton the 5' end ofthe gene. However, the site of Lynch et al described a cancer prone kindred APC cannot to Department of mutation be used predict with multiple members who had fewer than Epidemiology, The occurrence of this extracolonic cancer in 100 flat appearing adenomas, which were Johns Hopkins FAP pedigrees. located mainly in the right colon.35 After University School of (Gut 1996; 39: 867-869) molecular examination of this kindred and six Hygiene and Public Health, Baltimore, additional similar families36-38 demonstrated Maryland, USA Keywords: familial adenomatous polyposis, mutation in the very 5' region ofthe APC gene, G M Petersen adenomatous polyposis, hepatoblastoma, surveillance. this variant of FAP was termed attenuated Department of adenomatous polyposis coli by Spirio et al in Molecular Biology, 1 992.39 LabCorp, Research Familial adenomatous polyposis (FAP) is an Whether there is an association between Triangle Park, NC, USA autosomal dominant disorder characterised by APC gene mutation and development of M C Luce the development during adolescence and hepatoblastoma has not been confirmed. M C Cayouette young adulthood of hundreds to thousands of Identification of specific mutations conferring Correspondence to: colorectal adenomas.' If prophylactic colec- susceptibility to hepatoblastoma could serve as Dr F M Giardiello, Blalock 935, The Johns tomy is not performed, virtually all affected the basis for surveillance directed at kindreds Hopkins Hospital, 600 N subjects will develop colorectal cancer by the with these mutations. Therefore, we evaluated Wolfe Street, Baltirnore, Maryland 21287, USA. fifth decade of life. FAP can be associated with the site ofAPC gene mutation in seven familial Accepted for publication extraintestinal lesions ('Gardner syndrome') adenomatous polyposis kindreds, which 8 July 1996 such as soft tissue and bony tumours; desmoid included eight patients with hepatoblastoma. 868 Giardiello, Petersen, Brensinger, Luce, Cayouette, Bacon, Booker, Hamilton Methods expected because of their young ages; the Data were collected from The Johns Hopkins average age of diagnosis of adenomas in at risk Polyposis Registry, which contains 382 subjects is 15 years of age.' pedigrees with familial adenomatous polyposis. Mutation of the APC gene was found in all Patient information was obtained on all seven kindreds with a member who had Gut: first published as 10.1136/gut.39.6.867 on 1 December 1996. Downloaded from registry subjects through chart review and was hepatoblastoma. The mutations were re- subsequently computerised. The diagnosis of stricted to codons 141 to 1230, and all resulted hepatoblastoma in the study population was in a truncated APC protein. Although no verified by review of the original pathology family with hepatoblastoma had a mutation 3' slides (n=7) or report if the original slides were to codon 1230, there was no statistically not available (n=l). Seven of the cases were significant increase in frequency of hepato- reported in our previous publication.7 blastoma in registry pedigrees with mutations Genotyping was done from peripheral blood in codons 1 to 1230 (seven of 83) compared leucocytes in one affected member with FAP with families with mutations in codons 1231 to from each family after informed consent was 2843 (0 of 21) (p=0.34). No significant obtained. In five families, genomic DNA was correlations between site of mutation and age evaluated for germline mutations by RNase at diagnosis of hepatoblastoma or length of protection assay after polymerase chain survival after diagnosis were found. reaction amplification and then sequenced.40 41 In two families, the APC mutation was identified by in vitro synthesis protein assay,42 Discussion as described previously, and the site of Hepatoblastoma is a rapidly progressive mutation was estimated from the size of the tumour that carries a grave prognosis when truncated product. malignancy has spread beyond surgical The frequency of pedigrees with (n=7) and resection.6 In contrast, if diagnosed early, this without hepatoblastoma (n=97) in the Registry tumour is potentially curable with surgery, as was compared with the site of mutations in the occurred in two of our eight FAP patients who APC gene by x2 analysis. Correlation of age had longterm survival. Intensive screening of and survival with site of APC mutation was infants and children in FAP pedigrees with examined by calculation of Spearman's rank high risk for hepatoblastoma could be correlation coefficients. accomplished if it were possible to identify subjects on the basis of their APC mutation. In our study, hepatoblastoma occurred Results primarily in male patients (six of eight), which The Table lists the patients with hepato- is similar to the male predominance noted in blastoma in our Registry.7 All patients had one literature cases (18 of 25). This predominance parent with FAP and therefore were at 50% suggests that diagnostic attention to http://gut.bmj.com/ risk for the development of this autosomal hepatomegaly on physical examination or dominant disorder. Six of eight patients were abnormalities of liver chemistries deserve male and all were white, but there were no particular attention in boys in FAP families. statistically significant differences in demo- Furthermore, APC mutations in our pedigrees graphics between these patients and the with hepatoblastoma were restricted to codons Registry population. When all literature cases 141 to 1230. Characterisation of the spectrum (24 males, nine females with hepatoblastoma) of APC mutations in additional FAP families on October 2, 2021 by guest. Protected copyright. were compared with the Registry population, with hepatoblastoma is needed to determine if there was a statistically significant pre- this restriction can serve as a basis for dominance of male patients (p<0 01). All surveillance because, the distribution of patients in the current series were diagnosed mutations was not statistically different from with hepatoblastoma before 10 years of age. the site of mutations in pedigrees without Three patients survived hepatic resection and

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