Phenocopy breast cancer rates in Israeli BRCA1 BRCA2 mutation carrier families: is the risk increased in non-carriers?
- 169 Downloads
BRCA1 and BRCA2 mutation carriers have an increased risk for developing breast (and ovarian) cancer. Non-carriers from within such families (=true negatives) are counseled that their risk for developing breast cancer is similar to that of the average-risk population. Breast cancer diagnosed in a non-carrier from a family with a known mutation is coined phenocopy. The rate of breast cancer phenocopy and the risk for breast cancer in true negatives are unsettled. The rate of phenocopy breast cancer was assessed in non-carriers from Jewish families with a BRCA1 or BRCA2 mutation, identified at the Sheba medical center. Analysis was performed by t test for comparison of mean age at counseling or breast cancer diagnosis, and by calculating a standardized incidence ratio (SIR). Overall, 1318 females from 884 mutation carrying families (620 with BRCA1 264 with BRCA2 mutations) were genotyped, of whom 307 women from 245 families were assigned a true negative status (mean age at counseling 43.01 ± 13.03 years (range 19.7–92.8 years). Of these true negatives, 20 women (6.51–2.26% of families) developed breast cancer at a mean age of 54.1 ± 12.9 years (range 48.1 –60.1 years). The SIR for breast cancer in true negatives was not significantly different than the expected in the average-risk Israeli population [observed 20-expected 23.8 cases SIR = 0.84, 95% CI (0.51, 1.30)]. The rate of phenocopy breast cancer in non-carriers from Israeli BRCA1 BRCA2 mutation carrier families is 2.26% with no increased breast cancer risk over the average-risk population.
KeywordsBRCA1BRCA2 mutations Breast cancer risk True negatives Phenocopy
This study was sponsored by a grant from the Israel cancer association to the Israeli inherited breast cancer consortium. The Israel Cancer Association, a non-profit organization, sponsored a supplementary salary to Shiri Bernholtz. All other co-authors declare that they have no financial ties with the Israel Cancer Association, the organization that sponsored the research.
Conflict of interest
All authors declare that they have no conflict of interest regarding the data published herein.
- 1.Antoniou A, Pharoah PD, Narod S, Risch HA, Eyfjord JE, Hopper JL, Loman N, Olsson H, Johannsson O, Borg A, Pasini B, Radice P, Manoukian S, Eccles DM, Tang N, Olah E, Anton-Culver H, Warner E, Lubinski J, Gronwald J, Gorski B, Tulinius H, Thorlacius S, Eerola H, Nevanlinna H, Syrjäkoski K, Kallioniemi OP, Thompson D, Evans C, Peto J, Lalloo F, Evans DG, Easton DF (2003) Average risks of breast and ovarian cancer associated with BRCA1 or BRCA2 mutations detected in case series unselected for family history: a combined analysis of 22 studies. Am J Hum Genet 72(5):1117–1130PubMedCrossRefGoogle Scholar
- 3.Simchoni S, Friedman E, Kaufman B, Gershoni-Baruch R, Orr-Urtreger A, Kedar-Barnes I, Shiri-Sverdlov R, Dagan E, Tsabari S, Shohat M, Catane R, King MC, Lahad A, Levy-Lahad E (2006) Familial clustering of site-specific cancer risks associated with BRCA1 and BRCA2 mutations in the Ashkenazi Jewish population. Proc Natl Acad Sci USA 103(10):2774–3770CrossRefGoogle Scholar
- 10.Goldgar D, Venne V, Conner T, Buys S (2007) BRCA phenocopies or ascertainment bias? Med Genet 44(8):e86Google Scholar
- 11.Abeliovich D, Kaduri L, Lerer I, Weinberg N, Amir G, Sagi M, Zlotogora J, Heching N, Peretz T (1997) The founder mutations 185delAG and 5382insC in BRCA1 and 6174delT in BRCA2 appear in 60% of ovarian cancer and 30% of early-onset breast cancer patients among Ashkenazi women. Am J Hum Genet 60(3):505–514PubMedGoogle Scholar
- 12.Shiri Sverdlov R, Oefner P, Green L, Baruch RG, Wagner T, Kruglikova A, Haitchick S, Hofstra RM, Papa MZ, Mulder I, Rizel S, Bar Sade RB, Dagan E, Abdeen Z, Goldman B, Friedman E (2000) Mutational analysis of BRCA1 and BRCA2 in Ashkenazi and non-Ashkenazi Jewish women with familial breast cancer. Hum Mutat 16(6):491–501PubMedCrossRefGoogle Scholar
- 14.Breslow NE, Day NE (1987) Statistical methods in cancer research. IARC Workshop 25–27 May 1983. IARC Sci Publ 82:1–406Google Scholar