Prevalence of BRCA1 and BRCA2 gene mutations in patients with early-onset breast cancer

Central European BRCA2 mutation carriers: birth cohort status correlates with onset of breast cancer

BACKGROUND

Mutations in brca1 and 2 genes lead to a significant increase in the lifetime risk of developing breast (BC) and ovarian cancer (OC). There are indications that birth cohort can influence the cancer risk in brca1 mutation carriers. Therefore, we investigated the risks for BC and OC associated with brca2 mutations in a cohort of female mutation carriers of a genetically heterogeneous Central European population.

PATIENTS AND METHODS

This study included 246 women in whom a functional mutation in the brca2 gene had been identified at our institution. At the time of analysis, 153 women had developed cancer (142 BC, 9 OC, 2 BC and OC). Risks were estimated using the product limit method. The log rank test was used to compare different strata.

RESULTS

After correction for risk-reducing surgeries, the cumulative risk of developing cancer to age 70 was found to be 88% for BC (95% CI 81-95%) and 31% for OC (95% CI 17-45%). Female brca2 mutation carriers born in 1958 or later were at a significantly higher risk of developing BC at a younger age (p<0.001), while no such age cohort-dependent correlation was found for OC.

CONCLUSION

The age cohort-dependent early onset in BC in women born after 1958 strongly suggests the importance of exogenous factors such as lifestyle modification while this does not seem to be the case for OC. Female brca2 mutation carriers should be counseled about their age cohort-dependent breast cancer risk.

The impact of next generation sequencing on the analysis of breast cancer susceptibility: a role for extremely rare genetic variation?

Women with a family history of breast cancer have an approximately twofold elevated risk of the disease. Even though an array of genes has been associated with breast cancer risk the past two decades, variants within these genes jointly explain at most 40% of this familial risk. Many explanations for this 'missing heritability' have been proposed, including the existence of many very rare variants, interactions between genetic and environmental factors and structural genetic variation. In this review, we discuss how next generation sequencing will teach us more about the genetic architecture of breast cancer, with a specific focus on very rare genetic variants. While such variants potentially explain a substantial proportion of familial breast cancer, assessing the breast cancer risks conferred by them remains challenging, even if this risk is relatively high. To assess more moderate risks, epidemiological approaches will require very large patient cohorts to be genotyped for the variant, only achievable through international collaboration. How well we will be able to eventually resolve the missing heritability for breast cancer in a clinically meaningful way crucially depends on the underlying complexity of the genetic architecture.

Loss of the BRCA1-interacting helicase BRIP1 results in abnormal mammary acinar morphogenesis

BRIP1 is a DNA helicase that directly interacts with the C-terminal BRCT repeat of the breast cancer susceptibility protein BRCA1 and plays an important role in BRCA1-dependent DNA repair and DNA damage-induced checkpoint control. Recent studies implicate BRIP1 as a moderate/low-penetrance breast cancer susceptibility gene. However, the phenotypic effects of BRIP1 dysfunction and its role in breast cancer tumorigenesis remain unclear. To explore the function of BRIP1 in acinar morphogenesis of mammary epithelial cells, we generated BRIP1-knockdown MCF-10A cells by short hairpin RNA (shRNA)-mediated RNA interference and examined its effect in a three-dimensional culture model. Genome-wide gene expression profiling by microarray and quantitative RT-PCR were performed to identify alterations in gene expression in BRIP1-knockdown cells compared with control cells. The microarray data were further investigated using the pathway analysis and Gene Set Enrichment Analysis (GSEA) for pathway identification. BRIP1 knockdown in non-malignant MCF-10A mammary epithelial cells by RNA interference induced neoplastic-like changes such as abnormal cell adhesion, increased cell proliferation, large and irregular-shaped acini, invasive growth, and defective lumen formation. Differentially expressed genes, including MCAM, COL8A1, WIPF1, RICH2, PCSK5, GAS1, SATB1, and ELF3, in BRIP1-knockdown cells compared with control cells were categorized into several functional groups, such as cell adhesion, polarity, growth, signal transduction, and developmental process. Signaling-pathway analyses showed dysregulation of multiple cellular signaling pathways, involving LPA receptor, Myc, Wnt, PI3K, PTEN as well as DNA damage response, in BRIP1-knockdown cells. Loss of BRIP1 thus disrupts normal mammary morphogenesis and causes neoplastic-like changes, possibly via dysregulating multiple cellular signaling pathways functioning in the normal development of mammary glands.

Ten-year survival in patients with BRCA1-negative and BRCA1-positive breast cancer

PURPOSE

To estimate 10-year overall survival (OS) rates for patients with early-onset breast cancer, with and without a BRCA1 mutation, and to identify prognostic factors among those with BRCA1-positive breast cancer.

PATIENTS AND METHODS

A total of 3,345 women with stage I to III breast cancer, age ≤ 50 years, were tested for three founder mutations in BRCA1. Information on tumor characteristics and treatments received was retrieved from medical records. Dates of death were obtained from the vital statistics registry. Survival curves for the mutation-positive and -negative subcohorts were compared. Predictors of OS were determined using the Cox proportional hazards model.

RESULTS

Of the 3,345 patients enrolled onto the study, 233 (7.0%) carried a BRCA1 mutation. The 10-year survival rate for mutation carriers was 80.9% (95% CI, 75.4% to 86.4%); for noncarriers, it was 82.2% (95% CI, 80.5% to 83.7%). The adjusted hazard ratio (HR) associated with carrying a BRCA1 mutation was 1.81 (95% CI, 1.26 to 2.61). Among BRCA1 carriers with a small (< 2 cm) node-negative tumor, the 10-year survival rate was 89.9%. Among BRCA1 mutation carriers, positive lymph node status was a strong predictor of mortality (adjusted HR, 4.1; 95% CI, 1.8 to 8.9). Oophorectomy was associated with improved survival in BRCA1 carriers (adjusted HR, 0.30; 95% CI, 0.12 to 0.75).

CONCLUSION

The 10-year survival rate among women with breast cancer and a BRCA1 mutation is similar to that of patients without a BRCA1 mutation. Among women with a BRCA1 mutation, survival was much improved after oophorectomy.

CD44 gene polymorphisms in breast cancer risk and prognosis: a study in North Indian population

BACKGROUND

Cell surface biomarker CD44 plays an important role in breast cancer cell growth, differentiation, invasion, angiogenesis and tumour metastasis. Therefore, we aimed to investigate the role of CD44 gene polymorphisms in breast cancer risk and prognosis in North Indian population.

MATERIALS & METHODS

A total of 258 breast cancer patients and 241 healthy controls were included in the case-control study for risk prediction. According to RECIST, 114 patients who received neo-adjuvant chemotherapy were recruited for the evaluation of breast cancer prognosis. We examined the association of tagging SNP (rs353639) of Hapmap Gujrati Indians in Houston (GIH population) in CD44 gene along with a significant reported SNP (rs13347) in Chinese population by genotyping using Taqman allelic discrimination assays. Statistical analysis was done using SPSS software, version 17. In-silico analysis for prediction of functional effects was done using F-SNP and FAST-SNP.

RESULTS

No significant association of both the genetic variants of the CD44 gene polymorphisms was found with breast cancer risk. On performing univariate analysis with clinicopathological characteristics and treatment response, we found significant association of genotype (CT+TT) of rs13347 polymorphism with earlier age of onset (P = 0.029, OR = 0.037). However, significance was lost in multivariate analysis. For rs353639 polymorphism, significant association was seen with clinical tumour size, both at the genotypic (AC+CC) (P = 0.039, OR = 3.02) as well as the allelic (C) (P = 0.042, OR = 2.87) levels. On performing multivariate analysis, increased significance of variant genotype (P = 0.017, OR = 4.29) and allele (P = 0.025, OR = 3.34) of rs353639 was found with clinical tumour size. In-silico analysis using F-SNP, showed altered transcriptional regulation for rs353639 polymorphism.

CONCLUSIONS

These findings suggest that CD44 rs353639 genetic variants may have significant effect in breast cancer prognosis. However, both the polymorphisms- rs13347 and rs353639 had no effect on breast cancer susceptibility.

Immediate reconstruction following nipple-sparing mastectomy: one option for young breast cancer patients with early stage disease

The article entitled "Application of immediate breast reconstruction with silicon prosthetic implantation following bilateral mammary gland excision in treatment of young patients with early breast cancer" published in Journal of Thoracic Disease, examined the oncologic and cosmetic outcomes of the aforementioned procedures. We aimed to describe the unique circumstances of young breast cancer patients with early stage disease and highlight the multitude of surgical treatment and reconstructive options available to these patients.

Epidemiology and prognosis of breast cancer in young women

Breast cancer is the most common malignancy in women with 6.6% of cases diagnosed in young women below the age of 40. Despite variances in risk factors, Age Standardized Incidence Rates of breast cancer in young women vary little between different countries. Review of modifiable risk factors shows that long-term use of oral contraceptives, low body mass index (BMI) and high animal fat diet consumption are associated with increased risk of premenopausal breast cancer. Decreased physical activity and obesity increase risks of breast cancer in postmenopausal women, but data on premenopausal women rather shows that high BMI is associated with decreased risk of breast cancer. Non-modifiable risk factors such as family history and genetic mutations do account for increased risks of breast cancer in premenopausal women. Breast cancer in young women is associated with adverse pathological factors, including high grade tumors, hormone receptor negativity, and HER2 overexpression. This has a significant negative impact on the rate of local recurrence and overall survival. Moreover, younger women often tend to present with breast cancer at a later stage than their older counterparts, which further explains worse outcome. Despite these factors, age per se is still being advocated as an independent role player in the prognosis. This entails more aggressive treatment modalities and the need for closer monitoring and follow-up.

Quantitative assessment of the association between rs2046210 at 6q25.1 and breast cancer risk

Genome-wide association studies (GWAS) have identified several genetic susceptibility loci for breast cancer (BC). One of them, conducted among Chinese women, found an association of rs2046210 at 6q25.1 with the risk of BC recently. Since then, numerous association studies have been carried out to investigate the relationship between this polymorphism and BC risk in various populations. However, these have yielded contradictory results. We therefore performed a meta-analysis to clarify this inconsistency. Overall, a total of 235003 subjects based on 13 studies were included in our study. Significantly increased BC risk was detected in the pooled analysis [allele contrast: OR = 1.13, 95%CI = 1.10-1.17, P(Z) <10(-5), P(Q) <10(-4); dominant model: OR = 1.21, 95%CI = 1.14-1.27, P(Z) <10(-5), P(Q) <10(-4); recessive model: OR = 1.18, 95%CI = 1.12-1.24, P(Z) <10(-5), P(Q) = 0.04]. In addition, our data revealed that rs2046210 conferred greater risk in estrogen receptor (ER)-negative tumors [OR = 1.27, 95%CI = 1.15-1.40, P(Z) <10(-5), P(Q) <10(-4)] than in ER-positive ones [OR = 1.18, 95%CI = 1.09-1.28, P(Z) <10(-4), P(Q) = 0.0003]. When stratified by ethnicity, significant associations were found in Caucasian and Asian populations, but not detected among Africans. There was evidence of heterogeneity (P<0.05), however, the heterogeneity largely disappeared after stratification by ethnicity. The present meta-analysis demonstrated that the rs2046210 polymorphism may be associated with increased BC susceptibility, but this association varies in different ethnicities.

Mutational analysis of prohibitin--a highly conserved gene in Indian female breast cancer cases

Prohibitin (PHB) is a chaperone protein which is highly conserved evolutionarily. It shows significant homology with the Drosophila cc gene which is considered important for development and differentiation of Drosophila melanogaster. Investigations have revealed an involvement of PHB in cellular proliferation and development, apoptosis, signal transduction, mitochondrial function and regulation of the estrogen and androgen receptors. Therefore, we conducted the present study to analyze mutations in the highly conserved region in Indian female breast cancer patients. Conventional PCR-SSCP and Automated DNA sequencing were performed with a total of 105 breast cancer samples along with adjacent normal tissue. Of the total, 14.2% (15/105) demonstrated a mutation status of prohibitin observed in our study population. We identified a novel missense mutation (Thr>Ser), a novel deletion of T nucleotide in an intron adjacent to intron-exon boundary and a previously determined missense mutation (Val>Ala). A statistically significant correlation was obtained which suggested that prohibitin may be associated with tumor development and/or progression of at least some proportion of breast cancers.

Lack of association between LIG4 gene polymorphisms and the risk of breast cancer: a HuGE review and meta-analysis

OBJECTIVE

Non-homologous end joining (NHEJ) is one of the pathways of repair of DNA double-strand breaks. A number of genes involved in NHEJ have been implicated as breast cancer susceptibility genes such as LIG4. However, some studies have generated conflicting results. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis was to investigate association between LIG4 gene polymorphisms in the NHEJ pathway and breast cancer risk.

METHODS

Studies focusing on the relationship between LIG4 gene polymorphisms and susceptibility to breast cancer were selected from the Pubmed, Cochrane library, Embase, Web of Science, Springerlink, CNKI and CBM databases. Data were extracted by two independent reviewers and the meta-analysis was performed with Review Manager Version 5.1.6 and STATA Version 12.0 software, calculating odds ratios (ORs) with 95% confidence intervals (95%CIs).

RESULTS

According to the inclusion criteria, we final included seven studies with a total of 10,321 breast cancer cases and 10,160 healthy controls in the meta-analysis. The results showed no association between LIG4 gene polymorphisms (rs1805386 T>C, rs1805389 C>T, rs1805388 C>T and rs2232641 A>G) and breast cancer risk, suggesting that the mutant situation of these SNPs neither increased nor decreased the risk for breast cancer. In the subgroup analysis by Hardy-Weinberg equilibrium (HWE) and ethnicity, we also found no associations between the variants of LIG4 gene and breast cancer risk among HWE, non-HWE, Caucasians, Asians and Africans.

CONCLUSION

This meta-analysis suggests that there is a lack of any association between LIG4 gene polymorphisms and the risk of breast cancer.

BRCA1 and BRCA2 Gene Mutations Screening In Sporadic Breast Cancer Patients In Kazakhstan

BACKGROUND

A large number of distinct mutations in the BRCA1 and BRCA2 genes have been reported worldwide, but little is known regarding the role of these inherited susceptibility genes in breast cancer risk among Kazakhstan women.

AIM

To evaluate the role of BRCA1/2 mutations in Kazakhstan women presenting with sporadic breast cancer.

METHODS

We investigated the distribution and nature of polymorphisms in BRCA1 and BRCA2 entire coding regions in 156 Kazakhstan sporadic breast cancer cases and 112 age-matched controls using automatic direct sequencing.

RESULTS

We identified 22 distinct variants, including 16 missense mutations and 6 polymorphisms in BRCA1/2 genes. In BRCA1, 9 missense mutations and 3 synonymous polymorphisms were observed. In BRCA2, 7 missense mutations and 3 polymorphisms were detected. There was a higher prevalence of observed mutations in Caucasian breast cancer cases compared to Asian cases (p<0.05); higher frequencies of sequence variants were observed in Asian controls. No recurrent or founder mutations were observed in BRCA1/2 genes. There were no statistically significant differences in age at diagnosis, tumor histology, size of tumor, and lymph node involvement between women with breast cancer with or without the BRCA sequence alterations.

CONCLUSIONS

Considering the majority of breast cancer cases are sporadic, the present study will be helpful in the evaluation of the need for the genetic screening of BRCA1/2 mutations and reliable genetic counseling for Kazakhstan sporadic breast cancer patients. Evaluation of common polymorphisms and mutations and breast cancer risk in families with genetic predisposition to breast cancer is ongoing in another current investigation.

Individually tailored screening of breast cancer with genes, tumour phenotypes, clinical attributes, and conventional risk factors

Background:

We demonstrated how to comprehensively translate the existing and updated scientific evidence on genomic discovery, tumour phenotype, clinical features, and conventional risk factors in association with breast cancer to facilitate individually tailored screening for breast cancer.

Methods:

We proposed an individual-risk-score-based approach that translates state-of-the-art scientific evidence into the initiators and promoters affecting onset and subsequent progression of breast tumour underpinning a novel multi-variable three-state temporal natural history model. We applied such a quantitative approach to a population-based Taiwanese women periodical screening cohort.

Results:

Risk prediction for pre-clinical detectable and clinical-detected breast cancer was made by the two risk scores to stratify the underlying population to assess the optimal age to begin screening and the inter-screening interval for each category and to ascertain which high-risk group requires an alternative image technique. The risk-score-based approach significantly reduced the interval cancer rate as a percentage of the expected rate in the absence of screening by 30% and also reduced 8.2% false positive cases compared with triennial universal screening.

Conclusion:

We developed a novel quantitative approach following the principle of translational research to provide a roadmap with state-of-the-art genomic discovery and clinical parameters to facilitate individually tailored breast cancer screening.

Radiosensitivity in breast cancer assessed by the histone γ-H2AX and 53BP1 foci

BACKGROUND

High expression of constitutive histone γ-H2AX, a sensitive marker of DNA damage, might be indicative of defective DNA repair pathway or genomic instability. 53BP1 (p53-binding protein 1) is a conserved checkpoint protein with properties of a DNA double-strand breaks sensor. This study explores the relationship between the clinical radiosensitivity of tumor patients and the expression/induction of γ-H2AX and 53BP1 in vitro.

METHODS

Using immunostaining, we assessed spontaneous and radiation-induced foci of γ-H2AX and 53 BP1 in peripheral blood mononuclear cells derived from unselected breast cancer (BC) patients (n=57) undergoing radiotherapy (RT). Cells from apparently healthy donors (n=12) served as references.

RESULTS

Non-irradiated cells from controls and unselected BC patients exhibited similar baseline levels of DNA damage assessed by γ-H2AX and 53BP1 foci. At the same time, the γ-H2AX assay of in vitro irradiated cells revealed significant differences between the control group and the group of unselected BC patients with respect to the initial (0.5 Gy, 30 min) and residual (2 Gy, 24 h post-radiation) DNA damage. The numbers of 53BP1 foci analyzed in 35 BC patients were significantly higher than in controls only in case of residual DNA damage. A weak correlation was found between residual foci of both proteins tested. In addition, cells from cancer patients with an adverse acute skin reaction (grade 3) to RT showed significantly increased radiation-induced γ-H2AX foci and their protracted disappearance compared to the group of BC patients with normal skin reaction (grade 0-1). The mean number of γ-H2AX foci after 5 clinical fractions was significantly higher than that before RT, especially in clinically radiosensitive patients.

CONCLUSIONS

The γ-H2AX assay may have potential for screening individual radiosensitivity of breast cancer patients.

TRIAL REGISTRATION

http://www.krebshilfe.de/wir-foerdern.html.

Prediction of BRCA1 germ-line mutation status in patients with breast cancer using histoprognosis grade, MS110, Lys27H3, vimentin, and KI67

Family structure, lack of reliable information, cost, and delay are usual concerns when deciding to perform BRCA analyses. Testing breast cancer tissues with four antibodies (MS110, lys27H3, vimentin, and KI67) in addition to grade evaluation enabled us to rapidly select patients for genetic testing identification. We constituted an initial breast cancer tissue microarray, considered as a learning set, comprising 27 BRCA1 and 81 sporadic tumors. A second independent validation set of 28 BRCA1 tumors was matched to 28 sporadic tumors using the same original conditions. We investigated morphological parameters and 21 markers by immunohistochemistry. A logistic regression model was used to select the minimal number of markers providing the best model to predict BRCA1 status. The model was applied to the validation set to estimate specificity and sensibility. In the initial set, univariate analyses identified 11 markers significantly associated with BRCA1 status. Then, the best multivariate model comprised only grade 3, MS110, Lys27H3, vimentin, and KI67. When applied to the validation set, BRCA1 tumors were correctly classified with a sensitivity of 83% and a specificity of 81%. The performance of this model was superior when compared to other profiles. This study offers a new rapid and cost-effective method for the prescreening of patients at high risk of being BRCA1 mutation carriers, to guide genetic testing, and finally to provide appropriate preventive measures, advice, and treatments including targeted therapy to patients and their families.

Association between XRCC5, 6 and 7 gene polymorphisms and the risk of breast cancer: a HuGE review and meta-analysis

OBJECTIVE

Non-homologous end joining (NHEJ) is a pathway for repairing DNA double-strand breaks. Recent publications indicated that XRCC5, XRCC6 and XRCC7 genes may participate in the pathogenesis of breast cancer. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis was to investigate associations between XRCC5, XRCC6 and XRCC7 genetic polymorphisms in the NHEJ pathway and breast cancer risk.

METHODS

Studies focusing on the relationship between genetic polymorphisms in XRCC5, XRCC6 and XRCC7 genes and susceptibility to breast cancer were selected from the Pubmed, Cochrane library, Embase, Web of Science, Springerlink, CNKI and CBM databases. Data were extracted by two independent reviewers. The meta-analysis was performed with Review Manager Version 5.1.6 and STATA Version 12.0 software. The odds ratio (OR) with 95% confidence interval (95%CI) was calculated based on the extracted data.

RESULTS

According to the inclusion criteria, we final included seven studies with a total of 2,864 breast cancer cases and 3,060 healthy controls. Meta-analysis results showed that rs3835 (G>A) and rs828907 (G>T) in XRCC5 gene, and rs132793 (G>A) in XRCC6 gene might increase the risk of breast cancer, while rs132788 G>T and rs6002421 (A>G) might be protective factors. However, there was no relationship between XRCC7 genetic polymorphisms and the risk of breast cancer.

CONCLUSION

This meta-analysis suggests that the rs3835 G>A and rs828907 G>T in XRCC5 gene, rs6002421 (A>G), rs132788 (G>T) and rs132793 (G>A) in XRCC6 gene might be risk factors for breast cancer, while the rs132788 (G>T) and rs6002421 (A>G) in XRCC6 gene might be protective.

Analysis of DNA repair-related genes in breast cancer reveals CUL4A ubiquitin ligase as a novel biomarker of trabectedin response

Trabectedin is more active in nucleotide excision repair (NER)-efficient and homologous recombination repair (HRR)-deficient cells. As up to 25% of sporadic breast tumors present somatic inactivation of the HRR pathway (BRCAness phenotype), we sought to characterize trabectedin effect in BRCA1-proficient and BRCA1-null breast cancer cell lines. We evaluated whether HRR and NER gene expression correlates with trabectedin sensitivity and explored the response predictive value of the CUL4A ubiquitin ligase, which ubiquitinates NER pathway members. We characterized trabectedin cytotoxicity, cell-cycle effects, and BRCA1, BRCA2, XRCC3, XPG, ERCC1, and CUL4A expression in 10 breast cancer cell lines. Gene expression and trabectedin sensitivity association were determined in cell lines. Survival assays after trabectedin treatment were conducted in CUL4A-silenced BRCA1-proficient and -deficient cells. Because of limited phase II clinical trials evaluating trabectedin efficacy in patients with breast cancer, we assessed CUL4A immunohistochemical staining in a retrospective series of 118 sarcomas from trabectedin-treated patients to validate in vivo our in vitro observations. In cell lines, greater trabectedin sensitivity was associated with higher CUL4A expression and lower BRCA1/ERCC5, BRCA1/CUL4A, and XRCC3/CUL4A expression ratios. In agreement, BRCA1-deficient CUL4A-knockdown cells presented higher cell survival after trabectedin exposure than did scramble control cells. Lack of effect in BRCA1-proficient cells suggests that HRR impairment is key in CUL4A-mediated trabectedin sensitivity. High CUL4A expression in nontranslocation-related patients with sarcoma predicted improved progression-free survival [PFS; HR, 0.37; 95% confidence interval (CI), 0.20-0.68, P = 0.001] and overall survival (OS; HR, 0.44; 95% CI, 0.21-0.93, P = 0.026). Our observations support the notion of greater trabectedin activity in tumors exhibiting BRCAness and reveal CUL4A as a potential biomarker for definition of trabectedin target patients.

Mutation screening of the BRCA1 gene in early onset and familial breast/ovarian cancer in Moroccan population

Worldwide variation in the distribution of BRCA mutations is well recognised, and for the Moroccan population no comprehensive studies about BRCA mutation spectra or frequencies have been published. We therefore performed mutation analysis of the BRCA1 gene in 121 Moroccan women diagnosed with breast cancer. All cases completed epidemiology and family history questionnaires and provided a DNA sample for BRCA testing. Mutation analysis was performed by direct DNA sequencing of all coding exons and flanking intron sequences of the BRCA1 gene. 31.6 % (6/19) of familial cases and 1 % (1/102) of early-onset sporadic (< 45 years)were found to be associated with BRCA1 mutations. The pathogenic mutations included two frame-shift mutations (c.798_799delTT, c.1016dupA), one missense mutation (c.5095C>T),and one nonsense mutation (c.4942A>T). The c.798_799delTT mutation was also observed in Algerian and Tunisian BC families, suggesting the first non-Jewish founder mutation to be described in Northern Africa. In addition, ten different unclassified variants were detected in BRCA1, none of which were predicted to affect splicing. Most unclassified variants were placed in Align-GVGD classes suggesting neutrality. c.5117G>C involves a highly conserved amino acid suggestive of interfering with function (Align-GVGD class C55), but has been observed in conjunction with a deleterious mutation in a Tunisian family. These findings reflect the genetic heterogeneity of the Moroccan population and are relevant to genetic counselling and clinical management. The role of BRCA2 in BC is also under study.

Reproductive factors and risk of estrogen receptor positive, triple-negative, and HER2-neu overexpressing breast cancer among women 20-44 years of age

Aspects of reproductive history are among the most well-established breast cancer risk factors. However, relatively little is known about how they influence risk of different molecular subtypes of breast cancer, particularly among younger women. Using data from a population-based case-control study of women 20-44 years of age, we assessed the relationships between various reproductive factors and risk of estrogen receptor positive (ER+), triple-negative, and HER2-overexpressing breast cancers. Detailed reproductive histories were obtained through structured interviewer administered in-person questionnaires. Reproductive histories among control women (n = 941) were compared to those of ER+ cases (n = 781), triple-negative cases (n = 180), and HER2-overexpressing cases (n = 60) using polytomous logistic regression. Age at menarche, parity, and number of full-term pregnancies were similarly associated with risk of all three breast cancer subtypes. In contrast, age at first live birth, the interval between age at menarche and age at first birth, and breastfeeding were inversely associated with risk of triple-negative breast cancer (P values for trend 0.002, 0.006 and 0.018, respectively), but were not associated with risk of ER+ or HER2-overexpressing cancers. A strong inverse association between breastfeeding and risk of triple-negative breast cancer has now been consistently observed across numerous studies, and at present it is the most well-established protective factor for this aggressive and lethal form of breast cancer. Further studies clarifying the biological mechanisms underlying this relationship and confirming our results with respect to age at first birth and the interval between age at menarche and age at first birth are needed.

Population-based case-control association studies

This unit provides an overview of the design and analysis of population-based case-control studies of genetic risk factors for complex disease. Considerations specific to genetic studies are emphasized. The unit reviews basic study designs differentiating case-control studies from others, presents different genetic association strategies (candidate gene, genome-wide association, and high-throughput sequencing), introduces basic methods of statistical analysis for case-control data and approaches to combining case-control studies, and discusses measures of association and impact. Admixed populations, controlling for confounding (including population stratification), consideration of multiple loci and environmental risk factors, and complementary analyses of haplotypes, genes, and pathways are briefly discussed. Readers are referred to basic texts on epidemiology for more details on general conduct of case-control studies.

Familial breast cancer registry program in patients referred to the cancer institute of Iran

INTRODUCTION

Annually a considerable number of people die because of breast cancer, a common disease among women also in Iran. Identifying risk factors and susceptible people can lead to prevention or at least early diagnosis. Among susceptibility risks, 5-10% of patients have a family history predisposing factor which can influence the risk of incidence among the family. Having a registry program can be a more practical way to screen high risk families for preventive planning.

METHOD

Based on inclusion criteria, a questionnaire was prepared and after a pilot study on a small number of patients, actual data were collected on 400 patients and processed in SPSS 16.0.

RESULTS

Totally, 28.2%of the patients were younger than 40 years old and 36.8% had the included criteria for familial breast cancer (FBC). 102 patient's samples could be compared for receptor presentation. Similar to other studies, the number of triple negative breast cancers increased as the age decreased.

CONCLUSION

The high percentage of patients with FBC among 400 cases in this study demonstrates that in order to design an infrastructural diagnostic protocol and screening of patients with FBC, a precise survey related to frequency and founder mutations of FBC is needed nationwide.

Identification of the prevalent BRCA1 and BRCA2 mutations in the female population of Puerto Rico

Mutations in the breast cancer 1, early onset (BRCA1) and breast cancer 2 (BRCA2) genes are responsible for the majority of hereditary breast cancers. Knowledge of the incidence and prevalence of BRCA mutations in a specific population or ethnic group is necessary to provide accurate genetic counseling for breast cancer patients and their families; however, these data have not been gathered in the population of Puerto Rico. We conducted a retrospective study of female breast cancer patients undergoing genetic testing for BRCA mutations in the highest-volume breast surgery practices in San Juan, Puerto Rico. Data collection includes three-generation family cancer history and results from complete BRCA sequencing. A total of six different deleterious mutations were observed, including one mutation in BRCA1 and five mutations in BRCA2. Three recurrent mutations (BRCA1 del exon1-2, BRCA2 4150G>T, and BRCA2 6027del4) account for over 70% of all the BRCA mutations observed in this study population. This study examines for the first time the characteristics of hereditary breast cancer in Puerto Rico and assesses the accuracy of existing genetic risk assessment tools in that population. This data is expected to contribute to providing accurate and efficient tools for the clinical management of hereditary breast cancer in Puerto Rico.

Accuracy of BRCA1/2 mutation prediction models for different ethnicities and genders: experience in a southern Chinese cohort

Background

BRCA1/2 mutation prediction models (BRCAPRO, Myriad II, Couch, Shattuck-Eidens, BOADICEA) are well established in western cohorts to estimate the probability of BRCA1/2 mutations. Results are conflicting in Asian populations. Most studies did not account for gender-specific prediction. We evaluated the performance of these models in a Chinese cohort, including males, before BRCA1/2 mutation testing.

Methods

The five risk models were used to calculate the probability of BRCA mutations in probands with breast and ovarian cancers; 267 were non-BRCA mutation carriers (247 females and 20 males) and 43 were BRCA mutation carriers (38 females and 5 males).

Results

Mean BRCA prediction scores for all models were statistically better for carriers than noncarriers for females but not for males. BRCAPRO overestimated the numbers of female BRCA1/2 mutation carriers at thresholds ≥20% but underestimated if <20%. BRCAPRO and BOADICEA underestimated the number of male BRCA1/2 mutation carriers whilst Myriad II underestimated the number of both male and female carriers. In females, BRCAPRO showed similar discrimination, as measured by the area under the receiver operator characteristic curve (AUC) for BRCA1/2 combined mutation prediction to BOADICEA, but performed better than BOADICEA in BRCA1 mutation prediction (AUC 93% vs. 87%). BOADICEA had the best discrimination for BRCA1/2 combined mutation prediction (AUC 87%) in males.

Conclusions

The variation in model performance underscores the need for research on larger Asian cohorts as prediction models, and the possible need for customizing these models for different ethnic groups and genders.

Characteristics and spectrum of BRCA1 and BRCA2 mutations in 3,922 Korean patients with breast and ovarian cancer

This investigation is aimed at evaluating the epidemiologic characteristics of BRCA1/2 germline mutations in Korean patients with breast and ovarian cancer (BOC). We analyzed the entire mutational data of BRCA1/2 genes in BOC patients who were tested in Korea since the first Korean report of BRCA1 mutation in 1995 with the exception of the data covered in the Korean Hereditary Breast Cancer (KOHBRA) study, the project launched in 2007 for establishing BRCA1/2 carrier cohorts in Korea. In total, BRCA1/2 gene mutations of 3,922 Korean BOC patients were evaluated, including the unpublished data of 2,139 breast cancer patients examined by four Korean institutions and the data of 1,783 BOC patients covered in ten previous reports. Overall, 420 (150 distinct) pathogenic mutations were identified, 211 (73 distinct) in BRCA1 and 209 (77 distinct) in BRCA2. The majority (134 of 150) of the distinct mutations resulted in premature termination codon of the BRCA1/2 translation. BRCA1 c.4186-1593_4676-1465del was the only large genomic rearrangements mutation. Out of 150 distinct BRCA1/2 mutations, 84 (56 %) mutations were considered specific to Korean BOC. Eighty-five BRCA1/2 mutations were detected in at least two unrelated patients. These recurrent mutations account for 84.5 % (355 of 420) of mutations detected in the Korean population. In the pooled mutational data of BRCA1/2 genes, this study discovered the prevalence of BRCA1/2 mutations in the Korean BOC patients is similar to those found in other ethnic groups. Large genomic rearrangements in BRCA1/2 genes were infrequently detected among the Korean patients with BOC. There were several BRCA1/2 mutation candidates for founder mutations. To further establish a Korean cohort for BRCA1/2 mutations, the nationwide KOHBRA study is in progress.

Breast cancer in young women

About one in 300 women will be diagnosed with breast cancer before the age of 40. Advances in screening have not had an impact on mortality in women who are too young to be candidates for screening. Risk factors for early breast cancer include a lean body habitus and recent use of an oral contraceptive. Breast cancers in very young women are typically aggressive, in part owing to the over-representation of high-grade, triple-negative tumours, but young age is an independent negative predictor of cancer-specific survival. Very early age-of-onset also correlates strongly with the risk of local recurrence and with the odds of contralateral breast cancer. Given the high risks of local and distant recurrence in young women with invasive breast cancer, most (if not all) young patients are candidates for chemotherapy. It is hoped that by increasing breast cancer awareness, the proportion of invasive breast cancers that are diagnosed at 2.0 cm or smaller will increase and that this will lead to a reduction in mortality.

The application of nonsense-mediated mRNA decay inhibition to the identification of breast cancer susceptibility genes

BACKGROUND

Identification of novel, highly penetrant, breast cancer susceptibility genes will require the application of additional strategies beyond that of traditional linkage and candidate gene approaches. Approximately one-third of inherited genetic diseases, including breast cancer susceptibility, are caused by frameshift or nonsense mutations that truncate the protein product 1. Transcripts harbouring premature termination codons are selectively and rapidly degraded by the nonsense-mediated mRNA decay (NMD) pathway. Blocking the NMD pathway in any given cell will stabilise these mutant transcripts, which can then be detected using gene expression microarrays. This technique, known as gene identification by nonsense-mediated mRNA decay inhibition (GINI), has proved successful in identifying sporadic nonsense mutations involved in many different cancer types. However, the approach has not yet been applied to identify germline mutations involved in breast cancer. We therefore attempted to use GINI on lymphoblastoid cell lines (LCLs) from multiple-case, non- BRCA1/2 breast cancer families in order to identify additional high-risk breast cancer susceptibility genes.

METHODS

We applied GINI to a total of 24 LCLs, established from breast-cancer affected and unaffected women from three multiple-case non-BRCA1/2 breast cancer families. We then used Illumina gene expression microarrays to identify transcripts stabilised by the NMD inhibition.

RESULTS

The expression profiling identified a total of eight candidate genes from these three families. One gene, PPARGC1A, was a candidate in two separate families. We performed semi-quantitative real-time reverse transcriptase PCR of all candidate genes but only PPARGC1A showed successful validation by being stabilised in individuals with breast cancer but not in many unaffected members of the same family. Sanger sequencing of all coding and splice site regions of PPARGC1A did not reveal any protein truncating mutations. Haplotype analysis using short tandem repeat microsatellite markers did not indicate the presence of a haplotype around PPARGC1A which segregated with disease in the family.

CONCLUSIONS

The application of the GINI method to LCLs to identify transcripts harbouring germline truncating mutations is challenging due to a number of factors related to cell type, microarray sensitivity and variations in NMD efficiency.

Diathermy-induced injury may affect detection of occult tubal lesions at risk-reducing salpingo-oophorectomy

BACKGROUND

Electrosurgery-induced tubal thermal injury obscures cellular detail and hampers histomorphological assessment for occult pathology.

OBJECTIVE

The objectives of this study were to report on diathermy-related thermal injuries to the fallopian tube observed at RRSO and explore its potential impact on the detection of occult tubal epithelial lesions.

DESIGN

This study was composed of high-risk women from breast and/or ovarian cancer families attending a tertiary high-risk familial gynecologic cancer clinic. This was a retrospective case-control analysis of high-risk women who underwent RRSO. Cases were all women detected to have occult lesions (tubal atypia/carcinoma in situ/cancer) between January 2005 and December 2010. Control subjects were all women with normal tubal/ovarian histology between August 2006 and December 2007.

METHODS

Two pathologists performed histopathologic assessment for grade of thermal injury. Tubal diathermy injury rates were compared between cases and controls. Statistical analysis was undertaken using SPSS version 18. The Mann-Whitney U test compared age distributions; χ/Fisher tests, the difference between proportions, and γ test, the difference in ordinal variables between the groups.

RESULTS

A novel tubal thermal index to describe the severity of injury is reported. Lack of fimbrial thermal injury is twice as likely (odds ratio, 2.04; 95% confidence interval, 1.06-3.92) to be associated with detection of occult tubal pathology, whereas isthmic injury does not affect detection rate (P = 0.744). The groups were comparable with respect to age at RRSO (P = 0.531) and the presence of BRCA mutations (P = 0.192).

CONCLUSIONS

This report highlights the potential impact of electrosurgical thermal injury on detection of occult tubal pathology following RRSO. It is important for surgeons to avoid thermal injury to the distal end of the tube.

Id4 protein is highly expressed in triple-negative breast carcinomas: possible implications for BRCA1 downregulation

BRCA1 germline mutation carriers usually develop ER, PR and HER2 negative breast carcinoma. Somatic BRCA1 mutations are rare in sporadic breast cancers, but other mechanisms could impair BRCA1 functions in these tumors, particularly in triple-negative breast carcinomas (TNBCs). Id4, a helix-loop-helix DNA binding factor, blocks BRCA1 gene transcription in vitro and could downregulate BRCA1 in vivo. We compared Id4 immunoreactivity in 101 TNBCs versus 113 non-TNBCs, and correlated the results with tumor morphology and immunoreactivity for CK5/6, CK14, EGFR, and androgen receptor (AR). Id4 was present in 76 out of 101 (75 %) TNBCs: 40 (40 %) TNBCs displayed Id4 positivity in >50 % of neoplastic cells, 23 (23 %) in 5-50 %, and 13 (13 %) in <5 %. In contrast, only 6 (5 %) of 113 non-TNBCs showed focal Id4 positivity, limited to fewer than 5 % of the tumor (p < 0.0001). Id4 expression significantly associated with high histologic grade (p = 0.0002) and mitotic rate (p = 0.006). Id4 decorated all 12 TNBCs with large central acellular zone of necrosis in our series, with positive staining in 10-90 % of the cells. Id4 signal strongly correlated with cytokeratin CK14 reactivity (p < 0.0001), but not with CK5/6 and EGFR. All apocrine carcinomas in our series were positive for AR and most for EGFR, but they were negative for CK5/6, CK14, and Id4, with only two exceptions. Our results document substantial expression of Id4 in most TNBCs, which could result in functional downregulation of BRCA1 pathways in these tumors.

Familial breast cancer

Since the localization and discovery of the first high-risk breast cancer (BC) genes in 1990, there has been a substantial progress in unravelling its familial component. Increasing numbers of women at risk of BC are coming forward requesting advice on their risk and what they can do about it. Three groups of genetic predisposition alleles have so far been identified with high-risk genes conferring 40-85% lifetime risk including BRCA1, BRCA2 and TP53. Moderate risk genes (20-40% risk) including PALB1, BRIP, ATM and CHEK2, and a host of low-risk common alleles identified largely through genome-wide association studies. Currently, only BRCA1, BRCA2 and TP53 are used in clinical practice on a wide scale, although testing of up to 50-100 gene loci may be possible in the future utilizing next-generation technology.

Unravelling modifiers of breast and ovarian cancer risk for BRCA1 and BRCA2 mutation carriers: update on genetic modifiers

Pathogenic mutations in the tumour suppressor genes BRCA1 and BRCA2 confer increased risks for breast and ovarian cancer and account for approximately 15% of the excess familial risk of breast cancer amongst first-degree relatives of patients with breast cancer. There is considerable evidence indicating that these risks vary by other genetic and environmental factors clustering in families. In the past few years, based on the availability of genome-wide association data and samples from large collaborative studies, several common alleles have been found to modify breast or ovarian cancer risk for BRCA1 and BRCA2 mutation carriers. These common alleles explain a small proportion of the genetic variability in breast or ovarian cancer risk for mutation carriers, suggesting more modifiers remain to be identified. We review the so far identified genetic modifiers of breast and ovarian cancer risk and consider the implications for risk prediction. BRCA1 and BRCA2 mutation carriers could be some of the first to benefit from clinical applications of common variants identified through genome-wide association studies. However, to be able to provide more individualized risk estimates, it will be important to understand how the associations vary with different tumour characteristics and their interactions with other genetic and environmental modifiers.

Age of 40 years or younger is an independent risk factor for locoregional failure in early breast cancer: a single-institutional analysis in saudi arabia

Background. This study was undertaken to evaluate the impact of prognostic factors on the locoregional failure-free survival of early breast cancer patients. Methods. In this single-institutional study, 213 breast cancer patients were retrospectively analysed. Fifty-five of 213 patients were ≤40 years of age at diagnosis. The impact of patient- or treatment-related factors on the locoregional failure-free survival was assessed using the Kaplan-Meier method. The simultaneous impact of factors on the locoregional failure-free survival was assessed using the Cox proportional hazards regression analysis. Results. The median follow-up time of the censored patients was 22 months (mean 28 months, range 3-92 months). On univariate analysis, statistically significant factors for the locoregional failure-free survival were the age (≤40 versus >40 years), T stage (Tis, T0-2 versus T3-4), molecular tumor type (luminal A versus luminal B, Her2neu overexpression, or triple negative), and lymphovascular status (LV0 versus LV1). On multivariate analysis, age and T stage remained statistically significant. Conclusions. Being 40 years or younger has a statistically significant independent adverse impact on the locoregional failure-free survival of patients with early breast cancer.

Use of Monozygotic Twins in Search for Breast Cancer Susceptibility Loci

We have used Swedish monozygotic twins concordant for breast cancer to study genetic changes associated with the development of breast cancer. Because loss of heterozygosity (LOH) at a specific genomic region may reflect the presence of a tumour suppressor gene, loss of the same allele in both of the twins concordant for breast cancer may pinpoint a tumour suppressor gene that confers a strong predisposition to breast cancer. DNA samples extracted from the matched tumour and normal tissues of nine twin pairs were analysed for allelic imbalance using a set of microsatellite markers on chromosomes 1, 13, 16 and 17, containing loci with known tumour suppressor genes. The two main regions, where more twin pairs than expected had lost the same allele, were located at 16qtel, including markers D16S393, D16S305 and D16S413, and at 17p13, distal to the p53 locus. Our results show that the monozygotic twin model can be used to suggest candidate regions of potential tumour suppressor genes, even with a limited number of twin pairs.

Serum levels of IGF-I and BRCA penetrance: a case control study in breast cancer families

High serum levels of insulin-like growth factor I (IGF-I) are associated with an increased risk of sporadic breast cancer (BC). The aim of the present work is to evaluate the association between IGF-I and hereditary BC risk, using a case-control approach. The work represents an "ad interim" cross-sectional analysis of an ongoing study with a prospective design whose aim is to recruit a cohort of women belonging to high genetic risk families to test potential modulators of penetrance and prognosis. The odd of exposure to high serum IGF-I levels among women with a previous diagnosis of BC ("cases") was compared with the odd among unaffected "controls". The odds ratio (OR) and 95% confidence intervals (CIs) were estimated by unconditional logistic regression, controlling for confounders. We analysed 308 women (209 cases and 99 controls) at high genetic risk of BC. The adjusted OR of BC for the upper tertile of serum IGF-I versus the lowest one was 3.5 (95%CI 1.4-8.8). Excluding from the analysis 64 women under current Tamoxifen or GnRH analogues treatment, the adjusted OR of BC became 3.7 (95%CI 1.4-9.9). The association became stronger restricting the analysis to the 161 women (97 cases and 64 controls) with a proven BRCA mutation. If confirmed by a prospective approach, the association between IGF-I and familial BC will open further options for reducing BC risk in susceptible women.

Uptake of risk-reducing salpingo-oophorectomy in women carrying a BRCA1 or BRCA2 mutation: evidence for lower uptake in women affected by breast cancer and older women

BACKGROUND

Bilateral risk-reducing salpingo-oophorectomy (BRRSO) is the only effective way of reducing mortality from ovarian cancer. This study investigates uptake of BRRSO in 700 BRCA1/2 mutation carriers from Greater Manchester.

METHODS

Dates of last follow-up and BRRSO were obtained, and the following variables were investigated: ovarian cancer risk/gene, age and breast cancer history. The date of the genetic mutation report was the initiation for Kaplan-Meier analysis.

RESULTS

The uptake of BRRSO in BRCA1 mutation carriers was 54.5% (standard error 3.6%) at 5 years post testing compared with 45.5% (standard error 3.2%) in BRCA2 mutation carriers (P=0.045). The 40-59 years category showed the greatest uptake for BRRSO and uptake was significantly lower in the over 60 s (P<0.0001). Of the unaffected BRCA1 mutation carriers, 65% (standard error 5.1%) opted for surgery at 5 years post-testing compared with 41.1% (standard error 5.1%) in affected BRCA1 mutation carriers (P=0.045).

CONCLUSION

The uptake of BRRSO is lower in women previously affected by breast cancer and in older women. As there is no efficient method for early detection of ovarian cancer, uptake should ideally be greater. Counselling should be offered to ensure BRCA1/2 mutation carriers make an informed decision about managing their ovarian cancer risk.

Up-regulation of miR-1245 by c-myc targets BRCA2 and impairs DNA repair

BRCA2, a clinical prognostic factor, is significantly up-regulated in mRNA level, while its protein expression is often decreased in sporadic breast cancer. However, how BRCA2 protein expressions are suppressed in these tumors remains unknown. In this study, we demonstrated that miR-1245 directly suppressed BRCA2 3'-UTR and translation, impaired homologous recombination (HR)-mediated repair, reduced DNA damage-induced Rad51 nuclear foci, and rendered cells hypersensitive to γ-irradiation (IR), ultimately inducing high chromosomal abnormalities in normal breast cells and breast cancer cells. Conversely, inhibiting miR-1245 in breast cancer cells enhanced BRCA2 levels and induced resistance to IR. Furthermore, we demonstrated that c-myc up-regulated miR-1245 expression via direct binding to the miR-1245 promoter, which led to down-regulation of BRCA2 and reduction in HR efficiency. Significantly, miR-1245 levels in primary breast tumors correlated with c-myc overexpression and BRCA2 suppression. These findings uncover a BRCA2 regulatory and signaling pathway in sporadic breast cancer and support a functionally and clinically relevant epigenetic mechanism in cancer pathogenesis.

Implications of single nucleotide polymorphisms in CD44 exon 2 for risk of breast cancer

CD44 is a cell-surface glycoprotein involved in many cellular functions including lymphocyte activation, recirculation and homing, hematopoiesis and tumor metastasis, suggesting that CD44 may play an important role in breast cancer development. In this study, we examined whether CD44 exon 2 polymorphisms are associated with increased susceptibility to breast cancer. Direct nucleotide sequencing analysis showed that multiple single nucleotide polymorphisms were present in the CD44 exon 2 coding region in female patients with breast cancer. There was no significant difference in the frequency of any one single nucleotide polymorphism in the CD44 exon 2 coding region between patients with breast cancer and normal donors. However, CD44 polymorphisms in the CD44 exon 2 coding region were identified in approximately 40% of patients with breast cancer, which was significantly higher than in normal donors (odds ratio, 9.34; 95% confidence interval = 2.58-33.82; P < 0.0001). The Wilcoxon-Mann-Whitney test analysis showed that the patients with the CD44 polymorphisms in CD44 exon 2 coding sequence had breast cancer at earlier ages, 49 ± 3 versus 62 ± 2 years (P < 0.0005), and larger tumor burdens (4.9 ± 1.22 vs. 1.6 ± 0.15 mm, P < 0.01) at the time of diagnosis. Interestingly, African-American female patients having the CD44 polymorphisms in CD44 exon 2 coding sequence were diagnosed with breast cancer at very young age (41 ± 2 years). Our results show that CD44 exon 2 polymorphisms are associated with breast cancer development, and such analysis may be effectively used in the evaluation of risk, prediction of cancer, prevention, diagnosis, and epidemiological studies of breast cancer.

Mammographic density and breast cancer risk: current understanding and future prospects

Variations in percent mammographic density (PMD) reflect variations in the amounts of collagen and number of epithelial and non-epithelial cells in the breast. Extensive PMD is associated with a markedly increased risk of invasive breast cancer. The PMD phenotype is important in the context of breast cancer prevention because extensive PMD is common in the population, is strongly associated with risk of the disease, and, unlike most breast cancer risk factors, can be changed. Work now in progress makes it likely that measurement of PMD will be improved in the near future and that understanding of the genetics and biological basis of the association of PMD with breast cancer risk will also improve. Future prospects for the application of PMD include mammographic screening, risk prediction in individuals, breast cancer prevention research, and clinical decision making.

Family history of breast cancer in relation to tumor characteristics and mortality in a population-based study of young women with invasive breast cancer

BACKGROUND

Inherited predisposition may be associated with distinctive breast cancer phenotypes and/or mortality. Past studies have had inconsistent results and little is known about the contributions of screening and treatment.

METHODS

Within a population-based cohort of 1,260 women diagnosed with invasive breast cancer before age 46, we assessed how family history of breast cancer relates to mortality and tumor characteristics. Analyses were repeated excluding BRCA1/BRCA2 carriers. Medical records were reviewed for treatment history and tumors were centrally reviewed and tested. Cox proportional hazard modeling was used to assess the risk of dying in relation to family history; logistic regression was used to assess the association of family history to tumor characteristics.

RESULTS

Compared with women with no family history, women with first-degree family history of breast cancer had a 40% reduction (95% CI: 0.5-0.8) in the risk of dying. Mortality in women with only a second-degree family history was similar to those with no family history. The risk of dying was further reduced in those with a greater number of affected relatives. These relationships did not seem to be attributable to differences in screening, detection method, or treatment. Tumors in women with a first-degree family history had generally more favorable prognostic profiles.

CONCLUSION

Our findings suggest that breast cancer patients with a first-degree family history, compared with their counterparts without such a profile, may have a better prognosis.

IMPACT

These findings support the need for future research directed at replicating these results and identifying factors underlying this possible relationship.

Breast cancer in women under age 40 years: treatment by total mastectomy and reconstruction

INTRODUCTION

Breast cancer in women under 40 years of age is rare, accounting for approximately 5% of cases. The disease tends to be more aggressive in younger women. Younger age has been shown to be an independent predictive of breast reconstruction after total mastectomy. Treatment by total mastectomy and reconstruction is examined in relation to patient age.

METHODS

A retrospective review of all breast cancer patients treated by total mastectomy and reconstruction between 2005 and 2009 was performed by querying a prospective database.

RESULTS

A total of 671 patients underwent total mastectomy and reconstruction; of them, 106 (16%) aged <40 and 565 (84%) aged ≥40 years. Compared with older patients, the age <40 group was more likely to present with advanced breast cancer (P < 0.001), receive radiation (P = 0.006), undergo contralateral prophylactic mastectomy (P < 0.001) and bilateral reconstruction (P = 0.005), and undergo delayed reconstruction (P = 0.02). Transverse rectus abdominis musculocutaneous flap reconstruction was more common in the age ≥40 years (P = 0.03). Bilateral reconstruction was most commonly performed with tissue expansion regardless of patient age.

CONCLUSIONS

Breast reconstruction in women less than 40 years of age is influenced by advanced tumor stage and the necessity for adjuvant radiation therapy as well as an increased use of contralateral prophylactic mastectomy.

Interference with ER-α enhances the therapeutic efficacy of the selective CDK inhibitor roscovitine towards ER-positive breast cancer cells

In recent years many risk factors for the development of breast cancer that are linked to estrogens have been identified, and roscovitine (ROSC), a selective cyclin-dependent kinase (CDK) inhibitor, has been shown to be an efficient inhibitor of the proliferation of human breast cancer cells. Therefore, we have examined the possibility that interference with estrogen signaling pathways, using tamoxifen (TAM), a selective estrogen receptor modulator (SERM), could modulate the efficacy of treatment with ROSC. In conjunction with TAM, ROSC exhibited enhanced anti-proliferative activity and CDK inhibition, particularly in estrogen-dependent MCF-7 cells. The interaction between both drugs was synergistic. However, in ER-α-negative cells the interaction was antagonistic. Exposure of MCF-7 cells to ROSC abolished the activating phosphorylation of CDK2 and CDK7 at Ser(164/170). This in turn prevented the phosphorylation of the carboxyl-terminal repeat domain of RNA Polymerase II and ER-α at Ser(118), resulting in the down-regulation of the latter. Concomitantly, wt p53 was strongly activated by phosphorylation at Ser(46). Our results demonstrate that ROSC negatively affects the functional status of ER-α, making it potentially useful in the treatment of estrogen-dependent breast cancer cells.

Prevalence of BRCA1/2 mutations in sporadic breast/ovarian cancer patients and identification of a novel de novo BRCA1 mutation in a patient diagnosed with late onset breast and ovarian cancer: implications for genetic testing

In order to adequately evaluate the clinical relevance of genetic testing in sporadic breast and ovarian cancer patients, we offered comprehensive BRCA1/2 mutation analysis in patients without a family history for the disease. We evaluated the complete coding and splice site regions of BRCA1/2 in 193 sporadic patients. In addition, a de novo mutation was further investigated with ultra deep sequencing and microsatellite marker analysis. In 17 patients (8.8%), a deleterious germline BRCA1/2 mutation was identified. The highest mutation detection ratio (3/7 = 42.9%) was obtained in sporadic patients diagnosed with breast and ovarian cancer after the age of 40. In 21 bilateral breast cancer patients, two mutations were identified (9.5%). Furthermore, 140 sporadic patients with unilateral breast cancer were investigated. Mutations were only identified in patients diagnosed with breast cancer before the age of 40 (12/128 = 9.4% vs. 0/12 with Dx > 40). No mutations were detected in 17 sporadic male breast cancer and 6 ovarian cancer patients. BRCA1 c.3494_3495delTT was identified in a patient diagnosed with breast and ovarian cancer at the age of 52 and 53, respectively, and was proven to have occurred de novo at the paternal allele. Our study shows that the mutation detection probability in specific patient subsets can be significant, therefore mutation analysis should be considered in sporadic patients. As a consequence, a family history for the disease and an early age of onset should not be used as the only criteria for mutation analysis of BRCA1/2. The relatively high mutation detection ratio suggests that the prevalence of BRCA1/2 may be underestimated, especially in sporadic patients who developed breast and ovarian cancer. In addition, although rare, the possibility of a de novo occurrence in a sporadic patient should be considered.

Mutation analysis of RAD51L1 (RAD51B/REC2) in multiple-case, non-BRCA1/2 breast cancer families

Although a significant proportion of familial aggregation of breast cancer remains unexplained, many of the currently known breast cancer susceptibility genes, including BRCA1, BRCA2 and TP53, play a role in maintaining genome integrity by engaging in DNA repair. RAD51L1 is one of the five RAD51 paralogs involved in homologous recombination (HR) repair of DNA double-strand breaks (DSBs); it also interacts directly with p53. Deleterious mutations have been found in one RAD51 paralog, RAD51C (RAD51L2), in non-BRCA1/2 breast and ovarian cancer families, which suggests that all five paralogs are strong candidate breast cancer susceptibility genes. A genome-wide association study (GWAS) has already identified a single nucleotide polymorphism (SNP) deep within intron 10 of RAD51L1 as a risk locus for breast cancer. Based on its biological functions and association with RAD51C, there is reason to suggest that RAD51L1 (RAD51B/REC2) may also contain high risk mutations in the gene that give rise to multiple-case breast cancer families. In order to investigate this hypothesis, we have used high resolution melt (HRM) analysis to screen RAD51L1 for germline mutations in 188 non-BRCA1/2 multiple-case breast cancer families and 190 controls. We identified a total of seven variants: one synonymous, three intronic, and three previously identified SNPs, but no truncating or nonsense changes. Therefore, our results suggest that RAD51L1 is unlikely to represent a high-penetrance breast cancer susceptibility gene.

Breast and ovarian cancer: the forgotten paternal contribution

Five to 10% of all cases of breast and ovarian cancer are attributed to a heritable genetic predisposition. Transmission of BRCA1 and BRCA2 mutations is equally likely through maternal or paternal lineage; however, fewer referrals to cancer genetics clinics appear to be made for a paternal, than maternal, family history of breast and/or ovarian cancer. To examine this potential bias, a retrospective review of 315 patient and family charts was conducted by one familial cancer clinic in Toronto, Canada. Referral letters, risk estimates, and family histories were analyzed to identify significant differences between patients referred with maternal and paternal family histories. It was determined that patients are approximately five times more likely to be referred with a maternal family history of breast and/or ovarian cancer as compared to those with a paternal family history (p = <.0001). Individuals with a paternal family history were found to have a different, and higher, pattern of risk estimates (p = .00064). No significant difference was seen between the type of referrals sent by general practitioners, oncologists, and gynecologists. Recommendations to increase the awareness of paternal family history in assessing cancer risk are provided.