Breast cancer risks for BRCA1/2 carriers

Predictive role of single nucleotide polymorphism (rs11614913) in the development of breast cancer in Pakistani population

Aim: miRNAs play an important role in breast cancer (BC). Variations in miRNAs influence their maturation, expression and consequently regulation of their target genes. Materials & methods: In this study, single nucleotide polymorphism rs11614913 was genotyped in BC patients (n = 300) and 230 controls by employing tetra primer amplification refractory mutation system PCR and Sanger sequencing (Macrogen Korea). Results: A significant difference was observed in the genotypes through co-dominant (χ².#x00A0;= 42.03; p < 0.0001), additive (odds ratio [OR] = 0.6441 [0.4887-0.8490, 95% confidence interval]; p < 0.0019), dominant (OR = 0.3996 [0.2809-0.5686], p < 0.0001) and recessive (OR = 0.2993 [0.1220-0.7347], p < 0.009) statistical models showed decreased risk association of C allele with BC. Conclusion: Females having CT genotype are at higher risk of BC as compared with those having CC genotype.

Nutrition in the Prevention of Breast Cancer: A Middle Eastern Perspective

This paper reviews the escalating burden of breast cancer (BC) in the Middle East (ME) and the prevalence of modifiable risk factors and underscores opportunities to promote the prevention of the disease. Similar to more developed countries, BC is the most frequent cancer among women in countries of the ME, accounting for one-third of total cancer cases and 24% of total cancer deaths. Average age at BC diagnosis appears to be a decade earlier in Middle Eastern countries compared to the Western countries, and its incidence is predicted to further increase. Although incidence rates of BC are still lower in Middle Eastern countries than Western ones, mortality rates are similar and at times even higher. It is estimated that 30% of BC cases are due to environmental and lifestyle factors, such as obesity and diet and hence can be preventable. The ME suffers from surging rates of obesity, with eight of its countries ranking among the highest worldwide in obesity prevalence among adults aged 18 and above. ME countries with the highest prevalence of obesity that are among the top 20 worldwide include United Arab Emirates (UAE), Lebanon, Egypt, Libya, Qatar, Saudi Arabia, Jordan, and Kuwait with rates ranging from 30% in UAE to 37% in Kuwait. In parallel, studies in the ME have consistently showed a shift in dietary intake whereby traditional diets, rich in fruits and vegetables, are progressively eroding and being replaced by westernized diets high in energy and fat. Accumulating evidence is reporting convincing association between consumption of such westernized diets and higher BC risk. Addressing these risk factors and studying their association with BC in terms of their nature and magnitude in Middle Eastern countries could provide the basis for intervention strategies to lower the risk and alleviate the burden of BC in these countries.

Next Generation Sequencing Reveals High Prevalence of BRCA1 and BRCA2 Variants of Unknown Significance in Early-Onset Breast Cancer in African American Women

BACKGROUND

Variants of unknown significance (VUSs) have been identified in BRCA1 and BRCA2 and account for the majority of all identified sequence alterations. Notably, VUSs occur disproportionately in people of African descent hampering breast cancer (BCa) management and prevention efforts in the population. Our study sought to identify and characterize mutations associated with increased risk of BCa at young age.

METHODS

In our study, the spectrum of mutations in BRCA1 and BRCA2 was enumerated in a cohort of 31 African American women of early age at onset breast cancer, with a family history of breast or cancer in general and/or with triple negative breast cancer. To improve the characterization of the BRCA1 and BRCA2 variants, bioinformatics tools were utilized to predict the potential function of each of the variants.

RESULTS

Using next generation sequencing methods and in silico analysis of variants, a total of 197 BRCA1 and 266 BRCA2 variants comprising 77 unique variants were identified in 31 patients. Of the 77 unique variants, one (1.3%) was a pathogenic frameshift mutation (rs80359304; BRCA2 Met591Ile), 13 (16.9%) were possibly pathogenic, 34 (44.2%) were benign, and 29 (37.7%) were VUSs. Genetic epidemiological approaches were used to determine the association with variant, haplotype, and phenotypes, such as age at diagnosis, family history of cancer and family history of breast cancer. There were 5 BRCA1 SNPs associated with age at diagnosis; rs1799966 (P=.045; Log Additive model), rs16942 (P=.033; Log Additive model), rs1799949 (P=.058; Log Additive model), rs373413425 (P=.040 and .023; Dominant and Log Additive models, respectively) and rs3765640 (P=.033 Log Additive model). Additionally, a haplotype composed of all 5 SNPs was found to be significantly associated with younger age at diagnosis using linear regression modeling (P=.023). Specifically, the haplotype containing all the variant alleles was associated with older age at diagnosis (OR= 5.03 95% CI=.91-9.14).

CONCLUSIONS

Knowing a patient's BRCA mutation status is important for prevention and treatment decision-making. Improving the characterization of mutations will lead to better management, treatment, and BCa prevention efforts in African Americans who are disproportionately affected with aggressive BCa and may inform future precision medicine genomic-based clinical studies.

Comparison between CaGene 5.1 and 6.0 for BRCA1/2 mutation prediction: a retrospective study of 150 BRCA1/2 genetic tests in 517 families with breast/ovarian cancer

During the past years, several empirical and statistical models have been developed to discriminate between carriers and non-carriers of germline BRCA1/BRCA2 (breast cancer 1, early onset/breast cancer 2, early onset) mutations in families with hereditary breast or ovarian cancer. Among these, the BRCAPRO or CaGene model is commonly used during genetic counseling, and plays a central role in the identification of potential carriers of BRCA1/2 mutations. We compared performance and clinical applicability of BRCAPRO version 5.1 vs version 6.0 in order to assess diagnostic accuracy of updated version. The study was carried out on 517 pedigrees of patients with familial history of breast or ovarian cancer, 150 of which were submitted to BRCA1/2 mutation screening, according to BRCAPRO evaluation or to criteria based on familial history. In our study, CaGene 5.1 was more sensitive than CaGene 6.0, although the latter showed a higher specificity. Both BRCAPRO versions better discriminate BRCA1 than BRCA2 mutations. This study evidenced similar performances in the two BRCAPRO versions even if the CaGene 6.0 has underestimated the genetic risk prediction in some BRCA mutation-positive families. Genetic counselors should recognize this limitation and during genetic counseling would be advisable to use a set of criteria in order to improve mutation carrier prediction.

Breast cancer risks and risk prediction models

BRCA1/2 mutation carriers have a considerably increased risk to develop breast and ovarian cancer. The personalized clinical management of carriers and other at-risk individuals depends on precise knowledge of the cancer risks. In this report, we give an overview of the present literature on empirical cancer risks, and we describe risk prediction models that are currently used for individual risk assessment in clinical practice. Cancer risks show large variability between studies. Breast cancer risks are at 40-87% for BRCA1 mutation carriers and 18-88% for BRCA2 mutation carriers. For ovarian cancer, the risk estimates are in the range of 22-65% for BRCA1 and 10-35% for BRCA2. The contralateral breast cancer risk is high (10-year risk after first cancer 27% for BRCA1 and 19% for BRCA2). Risk prediction models have been proposed to provide more individualized risk prediction, using additional knowledge on family history, mode of inheritance of major genes, and other genetic and non-genetic risk factors. User-friendly software tools have been developed that serve as basis for decision-making in family counseling units. In conclusion, further assessment of cancer risks and model validation is needed, ideally based on prospective cohort studies. To obtain such data, clinical management of carriers and other at-risk individuals should always be accompanied by standardized scientific documentation.

Genetically at-risk status and individual agency. A qualitative study on asymptomatic women living with genetic risk of breast/ovarian cancer

For the last 20 years, genetic tests have allowed unaffected women to determine whether they are predisposed to developing breast/ovarian cancer due to BRCA1/2 gene mutations. In the event of adverse results, women receive a specific label associated with a set of medical recommendations: the genetically at-risk status. This qualitative study adopted a life-course perspective to understand the impact of this status on women's agency. Following a grounded theory design, retrospective biographical interviews were conducted in Switzerland between 2011 and 2013 with 32 unaffected women at risk of developing genetic breast/ovarian cancer and aware of their predisposition for at least three years. The results show that the genetically at-risk status conveys an invitation to transform health into a project, i.e., into a set of planned activities realized in collaboration with the medical system in order to reduce the risk of developing cancer. This health project shapes women's agency in three ways: it enhances, constrains and questions it, thus creating a sense of disorientation about what is considered rational and appropriate in terms of genetic risk management. Based on these findings, the paper concludes by stressing the paradoxes of the genetically at-risk status and the limits of the medical system in managing women designated with it. The paper also suggests that because of the disorientation intrinsic to their situation, genetically at-risk women have to reflexively construct their own health project from a range of available options in ways that are coherent and viable for themselves and their significant others. This process of reflexive construction may be called legitimation.

BRCA genetic screening in Middle Eastern and North African: mutational spectrum and founder BRCA1 mutation (c.798_799delTT) in North African

BACKGROUND

The contribution of BRCA1 mutations to both hereditary and sporadic breast and ovarian cancer (HBOC) has not yet been thoroughly investigated in MENA.

METHODS

To establish the knowledge about BRCA1 mutations and their correlation with the clinical aspect in diagnosed cases of HBOC in MENA populations. A systematic review of studies examining BRCA1 in BC women in Cyprus, Jordan, Egypt, Lebanon, Morocco, Algeria, and Tunisia was conducted.

RESULTS

Thirteen relevant references were identified, including ten studies which performed DNA sequencing of all BRCA1 exons. For the latter, 31 mutations were detected in 57 of the 547 patients ascertained. Familial history of BC was present in 388 (71%) patients, of whom 50 were mutation carriers. c.798_799delTT was identified in 11 North African families, accounting for 22% of total identified BRCA1 mutations, suggesting a founder allele. A broad spectrum of other mutations including c.68_69delAG, c.181T>G, c.5095C>T, and c.5266dupC, as well as sequence of unclassified variants and polymorphisms, was also detected.

CONCLUSION

The knowledge of genetic structure of BRCA1 in MENA should contribute to the assessment of the necessity of preventive programs for mutation carriers and clinical management. The high prevalence of BC and the presence of frequent mutations of the BRCA1 gene emphasize the need for improving screening programs and individual testing/counseling.

Cancer risks for BRCA1 and BRCA2 mutation carriers: results from prospective analysis of EMBRACE

BACKGROUND

Reliable estimates of cancer risk are critical for guiding management of BRCA1 and BRCA2 mutation carriers. The aims of this study were to derive penetrance estimates for breast cancer, ovarian cancer, and contralateral breast cancer in a prospective series of mutation carriers and to assess how these risks are modified by common breast cancer susceptibility alleles.

METHODS

Prospective cancer risks were estimated using a cohort of 978 BRCA1 and 909 BRCA2 carriers from the United Kingdom. Nine hundred eighty-eight women had no breast or ovarian cancer diagnosis at baseline, 1509 women were unaffected by ovarian cancer, and 651 had been diagnosed with unilateral breast cancer. Cumulative risks were obtained using Kaplan-Meier estimates. Associations between cancer risk and covariables of interest were evaluated using Cox regression. All statistical tests were two-sided.

RESULTS

The average cumulative risks by age 70 years for BRCA1 carriers were estimated to be 60% (95% confidence interval [CI] = 44% to 75%) for breast cancer, 59% (95% CI = 43% to 76%) for ovarian cancer, and 83% (95% CI = 69% to 94%) for contralateral breast cancer. For BRCA2 carriers, the corresponding risks were 55% (95% CI = 41% to 70%) for breast cancer, 16.5% (95% CI = 7.5% to 34%) for ovarian cancer, and 62% (95% CI = 44% to 79.5%) for contralateral breast cancer. BRCA2 carriers in the highest tertile of risk, defined by the joint genotype distribution of seven single nucleotide polymorphisms associated with breast cancer risk, were at statistically significantly higher risk of developing breast cancer than those in the lowest tertile (hazard ratio = 4.1, 95% CI = 1.2 to 14.5; P = .02).

CONCLUSIONS

Prospective risk estimates confirm that BRCA1 and BRCA2 carriers are at high risk of developing breast, ovarian, and contralateral breast cancer. Our results confirm findings from retrospective studies that common breast cancer susceptibility alleles in combination are predictive of breast cancer risk for BRCA2 carriers.

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.

BRCA1 polymorphisms and breast cancer epidemiology in the Western New York exposures and breast cancer (WEB) study

Results of studies for the association of BRCA1 genotypes and haplotypes with sporadic breast cancer have been inconsistent. Therefore, a candidate single nucleotide polymorphism (SNP) approach was used in a breast cancer case-control study to explore genotypes and haplotypes that have the potential to affect protein functions or levels. In a breast cancer case-control study, genotyping of BRCA1 polymorphisms Q356R, D693N, and E1038G was performed on 1,005 cases and 1,765 controls. Unconditional, polytomous logistic regression and χ(2) -tests were used to examine the associations of breast cancer with genotypes and haplotypes. In addition, interactions between genotype and smoking, benign breast disease, family history of breast cancer, body mass index (BMI), alcohol consumption, and hormonal risk factors, hormone receptor status, and breast cancer pathology were calculated also using logistic regression and χ(2) . Although sporadic breast cancer was not associated with BRCA1 genotypes or haplotypes overall or by menopausal status, there was evidence of an interaction between the E1038G BRCA1 genotype, smoking, and BMI among premenopausal women (P for interaction = 0.01 and 0.045, respectively) and between E1038G and D693N BRCA1 genotypes and hormone therapy use among postmenopausal women (P for interaction = 0.01 and 0.02, respectively). There were no other associations found between BRCA1 genotypes and stage, histological grade, or nuclear grade. However, the D693N SNP was associated with the risk of triple negative breast cancer (odds ratio = 2.31 95% confidence interval 1.08-4.93). The BRCA1 variants studied may play a role in the etiology of triple negative breast cancer and may interact with environmental factors such as hormone therapy or smoking and increase sporadic breast cancer risk.

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.

BRCA1 and BRCA2 families and the risk of skin cancer

BRCA1 and BRCA2 mutation carriers have elevated risks of breast and ovarian cancers. The risks for cancers at other sites remain unclear. Melanoma has been associated with BRCA2 mutations in some studies, however, few surveys have included non-melanoma skin cancer. We followed 2729 women with a BRCA1 or BRCA2 mutation for an average of 5.0 years. These women were asked to report new cases of cancer diagnosed in themselves or in their family. The risks of skin cancer were compared for probands with BRCA1 and BRCA2 mutations. Of 1779 women with a BRCA1 mutation, 29 developed skin cancer in the follow-up period (1.6%). Of the 950 women with a BRCA2 mutation, 28 developed skin cancer (3.0%) (OR = 1.83 for BRCA2 versus BRCA1; 95% CI 1.08-3.10; P = 0.02). The odds ratio for basal cell carcinoma was higher (OR = 3.8; 95% CI 1.5-9.4; P = 0.002). BRCA2 mutation carriers are at increased risk for skin cancer, compared with BRCA1 carriers, in particular for basal cell carcinoma.

Complete BRCA mutation screening in breast and ovarian cancer predisposition families from a North-Eastern Romanian population

Breast cancer is the most common cancer in women worldwide, including Romania, where its incidence has increased significantly during the last decade. Ovarian cancer is the fourth leading cause of mortality by cancer in women. BRCA1 and BRCA2 are major cancer predisposition genes, responsible for a large percentage of hereditary breast and ovarian cancer (HBOC) families. We investigated 17 patients from unrelated HBOC families in north-eastern Romania, screening for mutations in BRCA1 and BRCA2 by mutation-specific PCR and by dideoxy sequencing. We identified four BRCA1 and two BRCA2 mutations in the 17 families. The overall mutation frequency was 41% (7/17; 5 BRCA1 and 2 BRCA2). Two mutations (BRCA1 c.2241dupC and BRCA2 c.8680C>T) were novel and not listed in the BIC database. Two recurrent BRCA1 mutations (c.5266dupC and c.181T>G), previously described among Ashkenazi Jewish and Eastern European populations, were also found. Two unclassified variants (UV) were found, one of which was novel (BRCA2 c.4589A>G). Medical follow-up for mutation carriers was implemented. Our study is the first molecular investigation of the role of the BRCA genes in breast and ovarian cancer in Romania.

Single nucleotide polymorphisms in miRNA binding sites and miRNA genes as breast/ovarian cancer risk modifiers in Jewish high-risk women

We hypothesized that aberrant gene silencing by miRNA may affect mutant BRCA penetrance. To test this notion, frequency of single nucleotide polymorphisms (SNPs; n = 42) within predicted miRNA binding sites or miRNA precursors were determined and compared in 363 BRCA1 mutation carriers: asymptomatic (n = 160), breast cancer (n = 140) and ovarian cancer (n = 63) patients, and in 125 BRCA2 mutation carriers: asymptomatic (n = 48), breast cancer (n = 58) and ovarian cancer (n = 19) patients. Overall, 16 of 42 SNPs were polymorphic, 11 had a minor allele frequency greater than 5% and 9 of them maintained the Hardy-Weinberg Equilibrium. Based on Cox regression and Kaplan-Meier analyses, statistically significant differences were noted in BRCA2 mutation carriers by health status in 3 SNPs: CC homozygosity at rs6505162 increased ovarian cancer risk (RR 2.77; p = 0.028; 95% CI, 1.11-6.9); heterozygote SNP carriers of rs11169571 had an approximately 2 fold increased risk for developing breast/ovarian cancer, whereas heterozygotes of the rs895819 SNP had an approximately 50% reduced risk for developing breast/ovarian cancer. This study provides preliminary evidence for another regulatory level of penetrance of deleterious mutations in cancer predisposition genes.

Role of MSH6 and PMS2 in the dna mismatch repair process and carcinogenesis

In comparison with the mismatch repair genes MLH1 and MSH2, the genes MSH6 and PMS2 are relatively understudied with respect to cancer risk. However, some recent large studies of data combined from several sources, using analytic methods that appropriately condition on the varying methods of ascertainment, are producing reasonably precise estimates, which can be used for risk estimation in patients. To identify modifiers for risk in such carriers, a goal for epidemiologists to improve the health of carriers, such collaborative studies need to continue and expand to include additional mutation carriers in which lifestyle factors and DNA samples are available for analysis.

BRCA1, hormone, and tissue-specific tumor suppression

Germline mutations of BRCA1 predispose women to breast and ovarian cancers. Elucidating molecular mechanism of tissue- and gender-specific phenomena in BRCA1-related tumors is a key to our understanding of BRCA1 function in tumor suppression. This review summarizes studies in recent years on the link between BRCA1 and estrogen/progesterone signaling pathways, as well as discusses various models underscoring a triangle relationship among BRCA1, estrogen and genome instability.

BRCA mutation-negative women from hereditary breast and ovarian cancer families: a qualitative study of the BRCA-negative experience

BACKGROUND

When women from families with a known BRCA1 or BRCA2 mutation test negative for the family mutation, it is assumed that they will transition their personal cancer risk perception from high to average risk. However, there are scant data regarding the experience of mutation-negative women after genetic testing disclosure, particularly related to the shift of risk perception from assumed mutation-positive to actual mutation-negative. This study was designed to explore cancer risk perception and the experience of being a mutation-negative woman within a known BRCA1/2 mutation-positive family.

METHODS

We employed a qualitative descriptive design and convened a sample of 13 women who contributed in-depth, semi-structured telephone interviews (audio-recorded and transcribed verbatim) and performed qualitative content analysis with NVivo 2.0 software.

RESULTS

Six major content areas emerged from interview data: (i) rationale for initial involvement in the breast imaging study, (ii) rationale for continued participation, (iii) experience of living in a multiple-case family, (iv) risk perception: the personal meaning of mutation-negative status, (v) opinions regarding cancer aetiology and (vi) communication patterns between mutation-negative and mutation-positive family members.

CONCLUSIONS

Living in a hereditary breast and ovarian cancer family is a complex experience that affects cognitive, emotional and social functioning. Our findings indicate that mutation-negative women may have unmet psychosocial needs that must be addressed by health-care professionals, particularly in the primary-care setting following genetic disclosure of a potentially reassuring result regarding their lack of the very high cancer risks associated with BRCA1/2 mutations.

Validation study of the LAMBDA model for predicting the BRCA1 or BRCA2 mutation carrier status of North American Ashkenazi Jewish women

LAMBDA is a model that estimates the probability an Ashkenazi Jewish (AJ) woman carries an ancestral BRCA1 or BRCA2 mutation from her personal and family cancer history. LAMBDA is relevant to clinical practice, and its implementation does not require a computer. It was developed principally from Australian and UK data. We conducted a validation study using 1286 North American AJ women tested for the mutations 185delAG and 5382insC in BRCA1 and 6174delT in BRCA2. Most had a personal or family history of breast cancer. We observed 197 carriers. The area under the receiver operator characteristic (ROC) curve (a measure of ranking) was 0.79 [95% confidence interval (CI) = 0.77-0.81], similar to that for the model-generating data (0.78; 95% CI = 0.75-0.82). LAMBDA predicted 232 carriers (18% more than observed; p = 0.002) and was overdispersed (p = 0.009). The Bayesian computer program BRCAPRO gave a similar area under the ROC curve (0.78; 95% CI = 0.76-0.80), but predicted 367 carriers (86% more than observed; p < 0.0001), and was substantially overdispersed (p < 0.0001). Therefore, LAMBDA is comparable to BRCAPRO for ranking AJ women according to their probability of being a BRCA1 or BRCA2 mutation carrier and is more accurate than brcapro which substantially overpredicts carriers in this population.

Rationale for, and approach to, studying modifiers of risk in persons with a genetic predisposition to colorectal cancer

We address the issue of modifiers of risk for persons who are, on average, at high risk of colorectal cancer due to carrying germline genetic mutations. We discuss how to estimate risk and assess modifiers using data from mutation-carrying families. A critical analytical issue is the adjustment for how families have been sampled (ascertainment). Only a few published studies have made appropriate adjustments and have mostly reported lifetime risks of less than 50%. Incomplete penetrance and differences in risk by subcategories are consistent with the existence of genetic and/or environmental risk -modifiers. Data from large cohorts of carriers are required to study such modifiers with precision.

Non-Replication and Inconsistency in the Genome-Wide Association Setting

Non-replication and inconsistency had been common features in the search for common variants of candidate genes affecting the risk of complex diseases. They may continue to require attention in the current era, when massive hypothesis-free testing of genetic variants is feasible. An empirical evaluation of the early experience with genome-wide association (GWA) studies suggests several examples where proposed associations have failed to be replicated by subsequent investigations. Non-replication and inconsistency is defined here in the framework of cumulative meta-analysis. Ideally, associations exist, GWA finds them, and subsequent investigations should replicate them. However, a number of other possibilities need to be considered. No common genetic variants may associate with the phenotype of interest and GWA may find nothing; or associations may exist, but GWA may miss them. Associations that do not exist may be falsely selected by the GWA and subsequent studies may appropriately refute them or falsely replicate them. Finally, GWA may find true associations that are nevertheless falsely non-replicated in the subsequent studies; or associations may be genuinely inconsistent across study populations. A list of options is presented for consideration in each of these scenarios.

BRCA2 mutation-associated breast cancers exhibit a distinguishing phenotype based on morphology and molecular profiles from tissue microarrays

A distinct morphologic and molecular phenotype has been reported for BRCA1-associated breast cancers; however, the phenotype of BRCA2-associated breast cancers is less certain. To comprehensively characterize BRCA2-associated breast cancers we performed a retrospective case control study using tumors accrued through the Breast Cancer Family Registry. We examined the tumor morphology and hormone receptor status in 157 hereditary breast cancers with germline mutations in BRCA2 and 314 control tumors negative for BRCA1 and BRCA2 mutations that were matched for age and ethnicity. Tissue microarrays were constructed from 64 BRCA2-associated and 185 control tumors. Tissue microarray sections were examined for HER2/neu protein overexpression, p53 status and the expression of basal markers, luminal markers, cyclin D1, bcl2, and MIB1 by immunohistochemistry. The majority of BRCA2-associated tumors and control tumors were invasive ductal, no special-type tumors. In contrast to control tumors, BRCA2-associated cancers were more likely to be high grade (P<0.0001) and to have pushing tumor margins (P=0.0005). Adjusting for grade, BRCA2-associated tumors were more often estrogen receptor positive (P=0.008) and exhibited a luminal phenotype (P=0.003). They were less likely than controls to express the basal cytokeratin CK5 (P=0.03) or to overexpress HER2/neu protein (P=0.06). There was no difference in p53, bcl2, MIB1, or cyclin D1 expression between BRCA2-associated and control tumors. We have demonstrated, in the largest series of BRCA2-associated breast cancers studied to date, that these tumors are predominantly high-grade invasive ductal carcinomas of no special type and they demonstrate a luminal phenotype despite their high histologic grade.

BRCA1 genetic testing in 106 breast and ovarian cancer families from Southern Italy (Sicily): a mutation analyses

PURPOSE

To evaluate the contribution of germline BRCA1 mutations in the incidence of hereditary and familial Breast Cancer (BC) and/or Ovarian Cancer (OC) in patients from Southern Italy (in the region of Sicily) and to identify a possible association between the higher frequency of BRCA1 mutations and a specific familial profile.

EXPERIMENTAL DESIGN

A consecutive series of 650 patients with BC and/or OC diagnosed between 1999 and 2005 were recruited from the Southern Italian region of Sicily, after interview at the "Regional Reference Centre for the Characterization and Genetic Screening of Hereditary Tumors" at the University of Palermo. Genetic counselling allowed us to recruit a total of 106 unrelated families affected with breast and/or ovarian cancer screened for mutations occurring in the whole BRCA1 gene by automatic direct sequencing.

RESULTS

Germline BRCA1 mutations were found in 17 of 106 (16%) Sicilian families. The HBOC profile had a major frequency (66%) of mutations (P < 0.01). A total of 28 sequence variants was identified. Seven of these were pathogenic, 5 unknown biological variant (UV) and 16 polymorphisms. We also identified a pathological mutation (4843delC) as a possible Sicilian founder mutation.

CONCLUSIONS

The present study is the first BRCA1 disease-associated mutations analysis in Southern Italian families. The early age of onset of such tumors and the association with the HBOC familial profile could be two valid screening factors for the identification of BRCA1 mutation carriers. Finally, we identified a BRCA1 mutation with a possible founder effect.

Risk-Reduction Surgery Decisions in High-Risk Women Seen for Genetic Counseling

Women at greatest risk for hereditary breast and ovarian cancer may consider prophylactic removal of breasts or ovaries as a risk-reduction measure. This report describes uptake of risk-reduction mastectomy (RRM), risk-reduction oophorectomy (RRO), and related factors in 62 high-risk women who received genetic counseling. Seven (11%) participants underwent RRM and 13 (21%) underwent RRO. Of these women, 37% did not have BRCA testing, suggesting other factors influence decisions to undergo surgery. Women who had indicated (pre-genetic counseling) their intent not to have surgery chose not to have surgery. Information received during genetic counseling that women perceived as being most important for influencing risk-reduction surgery decisions was BRCA test result (positive or negative), followed by discussion of family cancer history. Reasons for indecision about risk-reduction surgery included genetic testing results, concerns about surgery, timing in life, and early menopause. The findings enhance our understanding of information that is helpful to women considering this surgery.

Prophylactic Oophorectomy Reduces Breast Cancer Penetrance During Prospective, Long-Term Follow-Up ofBRCA1Mutation Carriers

Purpose

Breast cancer penetrance estimates in BRCA1 mutation carriers have varied from 40% to 85%; this heterogeneity has been attributed to variations in risk among different study populations. No study has taken oophorectomy status into account in estimating penetrance. Because prophylactic oophorectomy reduces breast cancer risk by approximately 50%, we hypothesized that population differences in oophorectomy prevalence might significantly influence breast cancer penetrance estimates.

Methods

Females from multiple-case breast/ovarian cancer families that segregate deleterious BRCA1 mutations were observed prospectively for breast cancer incidence and oophorectomy.

Results

Within this cohort, 33 cases of breast cancer developed in 98 women with deleterious BRCA1 mutations during follow-up, yielding an estimated cumulative lifetime breast cancer risk of 80%. This estimate increased to 94% when the study participants were censored at the time of oophorectomy. Six of the 33 mutation-positive women who underwent oophorectomy during follow-up developed breast cancer, compared with 27 of 65 mutation carriers with intact ovaries (hazard ratio = 0.38; 95% CI, 0.15 to 0.97). Estimates of absolute breast cancer risk demonstrated that the protective effect of oophorectomy was strongest among women who were premenopausal at the time of surgery. When surgical status was ignored, the strong protective effect of oophorectomy, coupled with the high prevalence of the procedure in these families, led to a significantly lower estimate of the breast cancer penetrance in BRCA1 mutation carriers.

Conclusion

Differing rates of oophorectomy likely represent an underappreciated basis for a portion of the heterogeneity in estimated breast cancer penetrance described in BRCA mutation carriers, particularly mutation carriers from extensively affected, multiple-case families.

Younger birth cohort correlates with higher breast and ovarian cancer risk in European BRCA1 mutation carriers

Mutations in the BRCA1 gene result in an elevated risk of breast cancer (BC) and ovarian cancer (OC). However, risk estimates vary depending on the study population and statistical methodology used, and there are indications that the birth cohort and location of the mutation influence cancer risk. We investigated the risks for BC and OC associated with BRCA1 mutations in a young cohort of female mutation carriers who were identified by molecular genetic testing and belonged to a genetically heterogeneous Central European population. The study included 106 healthy and 158 affected carriers identified at an Austrian risk evaluation center. Risk estimation employed the product limit method. The log rank test was used to compare different strata. The risk of developing cancer to age 70 was found to be 85% for BC (95% CI 75-97%) and 53% for OC (95% CI 37-68%). Female mutation carriers born in 1958 or later were subject to a significantly higher risk of BC (P=0.005; 27% vs. 46% to age 40) and OC (P=0.006; 2% vs. 8% to age 40) than those born earlier. Mutations in exon 11 were associated with lower BC risk than mutations in exons 1-10 (P=0.008) and exons 12-24 (P=0.0006). OC risk was not influenced by mutation location (P=0.86). We conclude that female BRCA1 mutation carriers should be counseled about their cohort-dependent cancer risk. Further research into variables that affect cancer risk and are amenable to modification (e.g., lifestyle-related factors) should be considered a priority.

Population-based family studies in genetic epidemiology

Designs that involve families (the traditional strength of genetic epidemiology) and population-based sampling (the traditional strength of environmental epidemiology) allow investigation of both genes and environment, separately or together, and allow valid inference to the population. These case-control-family designs (including those involving twin pairs), can be regarded as retrospective cohort studies of relatives, and can be used for: determining familial risks and genetic models; estimating risk (penetrance) for measured genotypes; genetic association studies; stratifying risks by family history and known mutation status; and studying modifiers of risk in genetically susceptible individuals. Follow-up of families allows genetic and environmental risks to be studied prospectively. We discuss statistical methods, theoretical and practical strengths, limitations, and other issues. Given their versatility, population-based family studies could become a principal framework in epidemiology, and move genetics from its traditional focus on high-risk families to give it a wider clinical and population health relevance.

Cumulative Absolute Breast Cancer Risk for Young Women Treated for Hodgkin Lymphoma

BACKGROUND

Many women develop breast cancer after treatment for Hodgkin lymphoma (HL) at a young age. We estimated this future risk, taking into account age and calendar year of HL diagnosis, HL treatment information, population breast cancer incidence rates, and competing causes of death.

METHODS

Relative risks of breast cancer for categories defined by radiation dose to the chest (0, 20- < 40 Gy, or > or = 40 Gy) and use of alkylating agents (yes or no) were estimated from a case-control study conducted within an international population-based cohort of 3817 female 1-year survivors of HL diagnosed at age 30 years or younger from January 1, 1965, through December 31, 1994. To compute cumulative absolute risks of breast cancer, we used modified standardized incidence ratios to relate cohort breast cancer risks to those in the general population, enabling application of population-based breast cancer rates, and we allowed for competing risks by using population-based mortality rates in female HL survivors.

RESULTS

Cumulative absolute risks of breast cancer increased with age at end of follow-up, time since HL diagnosis, and radiation dose. For an HL survivor who was treated at age 25 years with a chest radiation dose of at least 40 Gy without alkylating agents, estimated cumulative absolute risks of breast cancer by age 35, 45, and 55 years were 1.4% (95% confidence interval [CI] = 0.9% to 2.1%), 11.1% (95% CI = 7.4% to 16.3%), and 29.0% (95% CI = 20.2% to 40.1%), respectively. Cumulative absolute risks were lower in women treated with alkylating agents.

CONCLUSIONS

Breast cancer projections varied considerably by type of HL therapy, time since HL diagnosis, and age at end of follow-up. These estimates are applicable to HL survivors treated with regimens of the past and can be used to counsel such patients and plan management and preventive strategies. Projections should be used with caution, however, in patients treated with more recent approaches, including limited-field radiotherapy and/or ovary-sparing chemotherapy.