In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 31, No. 15_suppl ( 2013-05-20), p. 4082-4082
Abstract:
4082 Background: CDH1 encodes E-cadherin; mutations (CDH1mut) increase the risk of diffuse gastric (DGC) and lobular breast cancers. Life-time risk of DGC is estimated at 80%. Current recommendations are prophylactic gastrectomy (PG) in CDH1mut carriers after age 20. Foci of DGC are found in some PG; others have none at PG, and some CDH1mut without PG never develop cancer. Identifying risk modifying alleles or other genomic events which increase the risk of DGC may improve understanding of DGC and may provide a biomarker for when to perform PG. Methods: For a Gastric Cancer Registry, we collected family pedigrees, germline DNA and FFPE tumor from CDH1mut DGC patients (pts) and their families. From 24 families, with 52 CDH1mut individuals, we identified 4 families in which a young CDH1mut pt developed advanced DGC while their CDH1mut parent and siblings had no clinical evidence of DGC. Several relatives had undergone PG with no DGC found. We hypothesize that there are risk modifying alleles and/or a “second hit” that causes variable penetrance and early onset of DGC in the young CDH1mut pts. Whole genome sequencing was performed on germ line DNA (Complete Genomics, Inc. Mountain View, CA); and whole exome sequencing on tumor specimens (MSKCC). Results: To date, 4 DGC pts and 8 relatives from 4 families have been studied. All 4 affected pts were women (ages 17, 25, 27, 42); their unaffected CDH1mut parents were 41, 51, 54, and 70 years old. The families are of Kenyan, Scandinavian, Italian, Eastern European, and Scottish origin. CDH1 mutations for the pts and their families were confirmed on WGS, and were as follows: 1451C 〉 A(pro484his);c. 1792C 〉 T (arg598ter);c. 1893dupA in exon 12;c. 1565+1G 〉 A (IVS10+1G 〉 A). Analysis of germline DNA for modifying alleles is being performed (Ingenuity Systems, Redwood, Ca.); whole exome sequencing of tumor to identify a possible "second hit" is underway. These data will be presented. Conclusions: Since at least some older pts with proven CDH-1mut do not develop DGC while their children do, CGH-1mut alone may not be sufficient to cause early onset DGC. We hope to identify the additional genomic events associated with early onset advanced DGC. Supported in part by grants from the Gerstner and DeGregorio Foundations.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2013.31.15_suppl.4082
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2013
detail.hit.zdb_id:
2005181-5
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