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Medline ® Abstract for Reference 38

of 'Genetic counseling and testing for hereditary breast and ovarian cancer'

Absence of genomic BRCA1 and BRCA2 rearrangements in Ashkenazi breast and ovarian cancer families.
Stadler ZK, Saloustros E, Hansen NA, Schluger AE, Kauff ND, Offit K, Robson ME
Breast Cancer Res Treat. 2010 Sep;123(2):581-5. Epub 2010 Mar 11.
A substantial proportion of Ashkenazi Jewish (AJ) breast and ovarian cancer families carry one of three founder mutations in BRCA1 (185delAG, 5382InsC) and BRCA2 (6174delT). Non-founder mutations are identified in another 2-4% of such families. The extent to which major genomic rearrangements in BRCA contribute to breast and ovarian cancer in the Ashkenazim is not well understood. We identified AJ individuals with breast and/or ovarian cancer undergoing hereditary breast/ovarian cancer risk assessment since 2006 without evidence of a deleterious mutation on BRCA gene sequencing who were screened for major gene rearrangements in BRCA1 and BRCA2. For each proband, the pre-test probability of identifying a deleterious BRCA mutation was estimated using the Myriad II model. We identified 108 affected individuals who underwent large rearrangement testing (80 breast cancer, 19 ovarian cancer, nine both breast and ovarian cancer). The mean estimated AJ specific pre-test probability of a deleterious mutation in BRCA1 and BRCA2 was 24.7% (range: 4.4-88.9%). No genomic rearrangements were identified in either the entire group or in the 26 subjects with pre-test mutation prevalence estimates exceeding 30%. Major gene rearrangements involving the BRCA1 and BRCA2 genes appear to contribute little tothe burden of inherited predisposition to breast and ovarian cancer in the Ashkenazim.
Department of Medicine, Clinical Genetics Service, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 192, New York, NY 10021, USA.