Since the proportion of families linked to BRCA1 is larger in Western early-onset breast cancer families than in late-onset ones, we also summed the LOD scores of five early-onset families.
The breast cancer susceptibility gene BRCA1 has been cloned and a second susceptibility gene, BRCA2, chromosomally mapped; will most breast and ovarian cancer turn out to be familial?
We have identified BRCA1 mutations in 12 of 30 (40%) Canadian families with breast and/or ovarian cancer, including six of the eight families (75%) that contained two cases of early-onset breast cancer and two cases of ovarian cancer.
We provide genetic evidence supporting the identity of the candidate gene for BRCA1 through the characterization of germline mutations in 63 breast cancer patients and 10 ovarian cancer patients in ten families with cancer linked to chromosome 17q21.
The identification and cloning of the BRCA1 gene is imminent, and will facilitate the screening and counselling of families at risk of breast cancer, and in the longer term may open up new therapeutic possibilities.
Loss of heterozygosity data from familial tumors suggest that BRCA1, a gene that confers susceptibility to ovarian and early-onset breast cancer, encodes a tumor suppressor.
Loss of heterozygosity data from familial tumors suggest that BRCA1, a gene that confers susceptibility to ovarian and early-onset breast cancer, encodes a tumor suppressor.
In a study of nine families with "site-specific" ovarian cancer (criterion: three or more cases of epithelial ovarian cancer and no cases of breast cancer diagnosed at age < 50 years) we have obtained evidence of linkage to the breast-ovarian cancer susceptibility gene, BRCA1 on 17q12-21.
A gene from chromosome region 17q12-q21, designated BRCA1, identified in 1990 by Dr Mary-Claire King and colleagues, predisposes to both cancer of the breast and the ovary.
One such gene (p53) has been identified and a second (BRCA1) has been precisely mapped in the human genome, but further breast cancer predisposition genes remain to be identified.
The imminent isolation of BRCA1 will make predictive testing for breast cancer a reality for many women and likely will pave the way for novel diagnostic and therapeutic strategies in the future.
Our results indicate that there is a gene(s) other than BRCA1 which predisposes to early-onset breast cancer in women and which confers a higher risk of male breast cancer.
In addition, many of the markers reveal genetic polymorphisms and may be tested in breast cancer families and in loss-of-heterozygosity studies of sporadic breast cancers to better define the BRCA1 gene candidate region.
The recent identification of the BRCA1 gene in early-onset hereditary site-specific breast cancer and the HBOC syndrome has led to new challenges for the genetic counselor.
Women with germline mutations in BRCA1 are estimated to have an 85% lifetime risk of developing breast cancer and an increased but as yet undetermined risk of ovarian cancer.