Linkage of early-onset familial breast and ovarian cancer to 11 markers on chromosome 17q12-q21 defines an 8-cM region which is very likely to include the disease gene BRCA 1.
Here, we report the analysis of three marker-disease recombinants in families that contain breast and ovarian cancer, two of which strongly suggest a location for BRCA1 telomeric to D17S702, a microsatellite polymorphism, and a third which suggests a location centromeric to EDH17B, the gene encoding estradiol-17B dehydrogenase.
Identification of BRCA1 should facilitate early diagnosis of breast and ovarian cancer susceptibility in some individuals as well as a better understanding of breast cancer biology.
In the context of high-risk families the most important genes are BRCA1 on chromosome 17q, which is associated with a high penetrance of both breast and ovarian cancer, and BRCA2 on chromosome 13q, which causes a high risk of breast cancer but a lower risk of ovarian cancer.
Since allelic loss has been reported in the 17q12-q21 region in breast and ovarian cancer and it appears that BRCA1 is not the target of the losses, we looked for somatic alterations in DLG2 in sporadic breast tumors.
These data are consistent with the hypothesis that BRCA1 mutations are involved in the etiology of hereditary ovarian carcinomas but occur rarely in sporadic tumors, and that the frequent allelic loss on chromosome 17q in this cancer type reflects the involvement of an additional tumor suppressor gene(s).
The recent cloning of a breast-ovarian cancer susceptibility gene (BRCA1), and determination of the locus of a related gene (BRCA2), offers potential for clinical genetic testing for breast cancer susceptibility.
Additionally, efforts using this methodology to generate a microclone library encompassing the early onset breast/ovarian cancer (BRCA1) gene will be presented.
Given the expected logistical problems in clinical management now that BRCA1 has been identified, we propose an interim period in which only families with a strong positive family history for early onset breast and/or ovarian cancer will be offered BRCA1 mutation testing.
A genetic recombinant in a breast-ovarian cancer family indicates a placement of BRCA1 telomeric to D17S776, and helps to define the region of assignment of the cancer susceptibility gene.
This method has been applied to chromosome bands 17q12-q21, a region that includes a gene (BRCA1) involved in early onset familial breast and ovarian cancer.
Our data support a tumour suppressor mechanism for BRCA1; somatic mutations and LOH may result in inactivation of BRCA1 in at least a small number of ovarian cancers.
We have characterized expression of the familial breast and ovarian cancer gene, BRCA1, in cases of non-hereditary (sporadic) breast cancer and analyzed the effect of antisense inhibition of BRCA1 on the proliferative rate of mammary epithelial cells.
In this paper we use data from families with evidence of linkage to BRCA1 to estimate the age-specific risks of breast and ovarian cancer in BRCA1-mutation carriers and to examine the variation in risk between and within families.
This review discusses recent insights into the roles of the p53 tumor-suppressor gene and growth factors in the development of ovarian cancer and describes the genes implicated in familial ovarian cancer syndromes related to the MSH2 (Lynch II) and BRCA1 (breast and ovarian cancer) genes.
The VH1-related human protein (VHR) gene was localized to human chromosome 17q21 in a region thought to contain the BRCA1 locus, a locus that confers susceptibility to breast and ovarian cancer.
A collaborative survey of 80 mutations in the BRCA1 breast and ovarian cancer susceptibility gene. Implications for presymptomatic testing and screening.