There is evidence that tamoxifen treatment of BRCA1 and BRCA2 carriers for prior breast cancer increases risk of endometrioid subtype endometrial cancer (EC), and suggestive evidence that BRCA1 and BRCA2 mutation carriers may be predisposed to EC in the absence of tamoxifen exposure. We assessed the association of EC with BRCA1 or BRCA2 mutation status in Australasian breast-ovarian families. Report of at least one case of EC was significantly greater in BRCA1-positive families (35/218 (16%); p = .03) and non-significantly greater in BRCA2-positive families (23/189 (12%); p = .6), compared to high-risk breast cancer families without a BRCA1/2 mutation (86/796 (11%)). EC was the first/concurrent cancer for 41% of EC cases with multiple cancer diagnoses from BRCA1/2 families, and early onset for most of these diagnoses. Mutation status was imputed for ungeno-typed individuals from 57 BRCA1/2 pedigrees reporting EC using BRCAPRO. Effects of genotype on EC diagnosis age, and interaction with tamoxifen therapy, were assessed using Cox proportional hazards regression analysis. EC risk was non-significantly marginally greater for BRCA1 carriers (hazard ratio = 1.25, 95%CI = 0.65–2.41), and BRCA2 carriers (HR = 1.12, 95%CI = 0.51–2.45), compared to non-carrier family members. Tamoxifen therapy was highly significantly associated with EC (HR = 6.68, 95%CI = 3.12–15.15; p = 1.7 x 10-6) in BRCA1/2 families, with no evidence for interaction between tamoxifen therapy and BRCA1/2 genotype. Our family-based study supports a 7-fold increase in EC risk with tamoxifen exposure for female family members from BRCA1/2 families. Early onset EC in carriers without tamoxifen use suggests that further study is required to assess association of modest EC risk with BRCA1/2 mutation status alone.

Mutations in the BRCA1 and BRCA2 genes confer very high risk of breast cancer (BC), but only account for about 25% of the observed familial clustering of BC. Antoniou et al. (2002) proposed a model which included the BRCA1 and BRCA2 genes, and a polygenic component which acted multiplicatively on the rate of onset of BC. We use this model to find premium rates for critical illness insurance: (a) given knowledge of an applicant's polygenotype; and (b) given knowledge of a family history of BC or ovarian cancer. We find that the polygenic component causes large variation in premium rates even among non-mutation carriers, therefore affecting the whole population. In some cases the polygenic contribution is protective enough to reduce or remove the additional risk of a BRCA1/2 mutation, leading to cases where it will be advantageous to disclose genetic test results which are adverse in absolute terms. Premiums based on family history are lower than those found in an earlier study which attributed all genetic BC risk to the BRCA1/2 genes.

The role of breast conservation in patients expressing BRCA1 and BRCA2 genetic mutations is controversial. A patient who was found to have bilateral synchronous breast cancers and expressed a BRCA genetic mutation was recently evaluated. The patient had a strong desire for breast preservation. This case and a review of the pertinent literature are presented to discuss the role of breast conservation and radiation in patients with BRCA1 or BRCA2 genetic mutations.

The cost of adverse selection in the life and critical illness (CI) insurance markets, brought about by restrictions on insurers' use of genetic test information, has been studied for a variety of rare single-gene disorders. Only now do we have a study of a common disorder (breast cancer) that accounts for the risk associated with multiple genes. Such a collection of genes is called a polygene. We take two approaches to modelling the severity of adverse selection which may result from insurers being unable to take account of tests for polygenes as well as major genes. First, we look at several genetic testing scenarios, with a corresponding range of possible insurance-buying behaviours, in a market model for CI insurance. Because a relatively large proportion of the population is exposed to adverse polygenic risk, the costs of adverse selection are potentially much greater than have been associated with rare single genes. Second, we use utility models to map out when adverse selection will appear, and which risk groups will cause it. Levels of risk aversion consistent with some empirical studies do not lead to significant adverse selection in our model, but lower levels of risk aversion could effectively eliminate the market.

Breast cancer is the most common cancer in women and a significant cause of death. Mutations of the oncosuppressor genes BRCA1 and BRCA2 are associated with a hereditary risk of breast cancer, and dysregulation of their expression has been observed in sporadic cases. Soya isoflavones have been shown to inhibit breast cancer in studies in vitro, but associations between the consumption of isoflavone-containing foods and breast cancer risk have varied in epidemiological studies. Soya is a unique source of the phytoestrogens daidzein (4′,7-dihydroxyisoflavone) and genistein (4′,5,7-trihydroxyisoflavone), two molecules that are able to inhibit the proliferation of human breast cancer cells in vitro. The aim of the present study was to determine the effects of genistein (5μg/ml) and daidzein (20μg/ml) on transcription in three human breast cell lines (one dystrophic, MCF10a, and two malignant, MCF-7 and MDA-MB-231) after 72h treatment. The different genes involved in the BRCA1 and BRCA2 pathways (GADD45A, BARD1, JUN, BAX, RB1, ERα, ERβ, BAP1, TNFα, p53, p21Waf1/Cip1, p300, RAD51, pS2, Ki-67) were quantified by real-time quantitative RT-PCR, using the TaqMan method and an ABI Prism 7700 Sequence Detector (Applied Biosystems). We observed that, in response to treatment, many of these genes were overexpressed in the breast cancer cell lines (MCF-7 and MDA-MB-231) but not in the dystrophic cell line (MCF10a).

Chemoprevention with tamoxifen and oophorectomy are thought to be effective in decreasing the incidence of breast cancer in women at increased risk for the disease. There is mounting data supporting the idea that hormonal interventions that reduce estrogen exposure to breast epithelium, such as prophylactic oophorectomy and tamoxifen, are effective in breast cancer prevention in both BRCA1 and BRCA2 mutations carriers. Several recent studies directly address the protective effect of tamoxifen and oophorectomy in BRCA mutation carriers and suggest that these endocrine manipulations decrease the risk of primary and secondary breast cancers. Ongoing studies aim to better define the effect of tamoxifen in these very high-risk women and determining whether factors, such as earlier age of use or prior prophylactic oophorectomy, impact tamoxifen's effect. Based on existing data, we recommend that women with deleterious mutations in BRCA1 or BRCA2 be informed of the beneficial effect of oophorectomy on breast cancer risk and that women who choose breast cancer screening instead of prophylactic mastectomy be offered tamoxifen as a prevention option.

Available mouse models of ductal carcinoma in situ (DCIS) and BRCA1-mutation-related breast cancer are reviewed. The best validated mouse models of human DCIS are the conditional estrogen receptor α in mammary tissue (CERM) model initiated by deregulated estrogen receptor α and the serial explant mouse model initiated by p53 deficiency. At present the most useful and best validated mouse model of BRCA1-mutation-related breast cancer uses the cre-lox system to make a conditional Brca1 deletion targeted to mammary epithelial cells. The major shortcoming of the non-conditional Brca1 models is the high incidence of non-mammary tumor development. The use of mammary gland transplants or explants from these mice into nude hosts is one approach that could be used to circumvent this deficiency. Development and validation of a Brca1-mutation-related mouse model of basal cell breast cancer is an important next step.

For the majority of women with early-stage breast cancer, conservative management with breast conserving surgery plus radiotherapy is widely embraced. However, in patients with germline mutations of BRCA1 and BRCA2, the safety of breast conservation therapy remains controversial. These breast cancer susceptibility genes are associated with an increased risk of second cancers, although the prognosis of BRCA1 or BRCA2 breast cancer is similar to patients with sporadic breast cancer. Preclinical evidence for radiosensitivity has prompted concern for radiation-induced complications in patients with genetic breast cancer. There is limited literature on the safety breast conservation therapy in patients with BRCA1 and BRCA2 mutations. The largest published study reported acute and chronic radiation toxicity results and noted no adverse sequelae in the genetic cohort [1]. Selected published studies demonstrate recurrence rates and overall survival comparable to sporadic controls [1–3]. A series with longer follow-up reported an increase in late second-primary breast cancers, highlighting the need for preventative strategies [4]. Tamoxifen and oophorectomy have a potential role in modifying the rate of second events, and thereby improving the safety of breast conservation therapy.

Breast cancer is one of the most common causes of cancer-related mortality in women. It affects more than one in nine women over their lifetime. Although most breast cancers are sporadic, the genetics and molecular biology of the heritable forms of breast cancer have provided valuable insights into not only breast cancer but also cancers in general. Among the mutations linked to heritable breast cancers, the mutations in the breast cancer 1 (BRCA1) gene are the best characterised. The BRCA1 gene encodes a nuclear protein that is important for maintaining genome integrity. However, a growing list of BRCA1-associated proteins suggests that BRCA1 has diverse and unexpected functions.

Background: In 1994/95, two genes, BRCA1/2, associated with a predisposition to breast or ovarian cancer were identified. Genetic testing of deleterious BRCA1/2 mutations consequently can be proposed to individuals with a family history of breast or ovarian cancer to identify who is at risk. The granting of U.S. patents on BRCA1/2 to a privately owned company has led to the monopoly use of a unique technique (Direct Sequencing of the gene, DS) for BRCA1/2 testing in this country. Alternative strategies using prescreening techniques, however, have been experienced worldwide.

Methods: On the basis of data collected at three laboratories of French public hospitals, we carried out a cost-effectiveness study comparing DS to 19 alternative strategies with the number of deleterious BRCA1 mutations detected as the outcome.

Results: Results show that the DS strategy presents the highest average cost per mutation detected (9,882.5 °) and that there exist strategies using prescreening techniques that can reach similar effectiveness while reducing total costs. Moreover, other strategies can obtain a four- to sevenfold reduction in the average cost per mutation detected as soon as some rates of false negatives (2% to 13%) are deemed to be acceptable.

Conclusions: Results suggest that gene patents with a very broad scope, covering all potential medical applications, may prevent health care systems from identifying and adopting the most efficient genetic testing strategies due to the monopoly granted for the exploitation of the gene. Policy implications for regulatory authorities, in the current context of the extension of BRCA1/2 patents in other countries, are discussed.

Current evidence strongly supports a role for the breast tumour suppressor genes, BRCA1 and BRCA2, in both normal development and carcinogenesis. In vitro observations reported that BRCA1 and BRCA2 are expressed in a cell cycle-dependent manner. Interestingly, differences in the actions of n-3 and n-6 polyunsaturated fatty acids have been observed: while the n-3 polyunsaturated fatty acids have been described to reduce pathological cell growth, the n-6 polyunsaturated fatty acids have been found to induce tumour proliferation. Here, we examined the expression of BRCA1 and BRCA2 in breast cell lines after treatment with polyunsaturated fatty acids. Real-time quantitative polymerase chain reaction determinations conclusively demonstrated increases in BRCA1 and BRCA2 mRNA expressions in MCF7 and MDA-MB 231 tumour cell lines after treatment with n-3 polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid), but no variation was noticed with the n-6 polyunsaturated fatty acid (arachidonic acid). On the other hand, no variation of the expression of BRCA1 and BRCA2 mRNA was detected in MCF10a normal breast cell line treated by polyunsaturated fatty acids. The level of BRCA1 and BRCA2 proteins quantified by affinity chromatography remained unchanged in tumour (MCF7, MDA-MB 231) and normal (MCF10a) breast cell lines. We suggest the presence of a possible transcriptional or post-transcriptional regulation of BRCA1 and BRCA2 after n-3 polyunsaturated fatty acid treatment in breast tumour cells.