Breast Cancer Family Registry Research Articles

Elevation of methylated DNA in KILLIN/PTEN in the plasma of patients with thyroid and/or breast cancer.

Around 80% of mutations in the PTEN gene have been reported to be associated with diseases such as Cowden syndrome, which is an autosomal dominant disorder associated with an increased risk of developing breast, thyroid, and endometrial neoplasms. Recent studies have also demonstrated that KILLIN, which is located proximally to PTEN, shares the same transcription start site, and is assumed to be regulated by the same promoter, but is transcribed in the opposite direction. In this regard, we postulate that there may be a connection between KILLIN/PTEN genes and breast and thyroid cancers. Using real-time quantitative polymerase chain reaction (qPCR), we found that expression of KILLIN, but not PTEN, was significantly decreased in 23 Chinese women with a personal history of breast and thyroid cancer or a personal history of breast cancer and a family history of thyroid cancer, or vice versa, and at least two persons in the family with thyroid cancer or at a young age <40 years, when compared with healthy controls (P<0.0001). No PTEN mutations were found in these 23 patients. We then developed a simple methylation-sensitive restriction enzyme digestion followed by real-time quantitative assay to quantify plasma methylated KILLIN/PTEN DNA in these patients. Plasma levels of methylated KILLIN/PTEN DNA were significantly increased in these patients when compared with healthy controls (P<0.05). This study shows that plasma methylated KILLIN/PTEN DNA was significantly elevated, suggesting hypermethylation of the KILLIN/PTEN promoter in breast and thyroid cancer patients.

Rare key functional domain missense substitutions in MRE11A, RAD50, and NBN contribute to breast cancer susceptibility: results from a Breast Cancer Family Registry case-control mutation-screening study.

IntroductionThe MRE11A-RAD50-Nibrin (MRN) complex plays several critical roles related to repair of DNA double-strand breaks. Inherited mutations in the three components predispose to genetic instability disorders and the MRN genes have been implicated in breast cancer susceptibility, but the underlying data are not entirely convincing. Here, we address two related questions: (1) are some rare MRN variants intermediate-risk breast cancer susceptibility alleles, and if so (2) do the MRN genes follow a BRCA1/BRCA2 pattern wherein most susceptibility alleles are protein-truncating variants, or do they follow an ATM/CHEK2 pattern wherein half or more of the susceptibility alleles are missense substitutions?MethodsUsing high-resolution melt curve analysis followed by Sanger sequencing, we mutation screened the coding exons and proximal splice junction regions of the MRN genes in 1,313 early-onset breast cancer cases and 1,123 population controls. Rare variants in the three genes were pooled using bioinformatics methods similar to those previously applied to ATM, BRCA1, BRCA2, and CHEK2, and then assessed by logistic regression.ResultsRe-analysis of our ATM, BRCA1, and BRCA2 mutation screening data revealed that these genes do not harbor pathogenic alleles (other than modest-risk SNPs) with minor allele frequencies >0.1% in Caucasian Americans, African Americans, or East Asians. Limiting our MRN analyses to variants with allele frequencies of <0.1% and combining protein-truncating variants, likely spliceogenic variants, and key functional domain rare missense substitutions, we found significant evidence that the MRN genes are indeed intermediate-risk breast cancer susceptibility genes (odds ratio (OR) = 2.88, P = 0.0090). Key domain missense substitutions were more frequent than the truncating variants (24 versus 12 observations) and conferred a slightly higher OR (3.07 versus 2.61) with a lower P value (0.029 versus 0.14).ConclusionsThese data establish that MRE11A, RAD50, and NBN are intermediate-risk breast cancer susceptibility genes. Like ATM and CHEK2, their spectrum of pathogenic variants includes a relatively high proportion of missense substitutions. However, the data neither establish whether variants in each of the three genes are best evaluated under the same analysis model nor achieve clinically actionable classification of individual variants observed in this study.

Does perceived risk predict breast cancer screening use? Findings from a prospective cohort study of female relatives from the Ontario site of the Breast Cancer Family Registry

While the relationship between perceived risk and breast cancer screening use has been studied extensively, most studies are cross-sectional. We prospectively examined this relationship among 913 women, aged 25–72 with varying levels of familial breast cancer risk from the Ontario site of the Breast Cancer Family Registry. Associations between perceived lifetime breast cancer risk and subsequent use of mammography, clinical breast examination (CBE) and genetic testing were assessed using logistic regression. Overall, perceived risk did not predict subsequent use of mammography, CBE or genetic testing. Among women at moderate/high familial risk, those reporting a perceived risk greater than 50% were significantly less likely to have a CBE (odds ratio (OR) = 0.52, 95% confidence interval (CI): 0.30–0.91, p = 0.04), and non-significantly less likely to have a mammogram (OR = 0.70, 95% CI: 0.40–1.20, p = 0.70) or genetic test (OR = 0.61, 95% CI: 0.34–1.10, p = 0.09) compared to women reporting a perceived risk of 50%. In contrast, among women at low familial risk, those reporting a perceived risk greater than 50% were non-significantly more likely to have a mammogram (OR = 1.13, 95% CI: 0.59–2.16, p = 0.78), CBE (OR = 1.11, 95% CI: 0.63–1.95, p = 0.74) or genetic test (OR = 1.29, 95% CI: 0.50–3.33, p = 0.35) compared to women reporting a perceived risk of 50%. Perceived risk did not significantly predict screening use overall, however this relationship may be moderated by level of familial risk. Results may inform risk education and management strategies for women with varying levels of familial breast cancer risk.

Assessing the goodness of fit of personal risk models.

We describe a flexible family of tests for evaluating the goodness of fit (calibration) of a pre-specified personal risk model to the outcomes observed in a longitudinal cohort. Such evaluation involves using the risk model to assign each subject an absolute risk of developing the outcome within a given time from cohort entry and comparing subjects' assigned risks with their observed outcomes. This comparison involves several issues. For example, subjects followed only for part of the risk period have unknown outcomes. Moreover, existing tests do not reveal the reasons for poor model fit when it occurs, which can reflect misspecification of the model's hazards for the competing risks of outcome development and death. To address these issues, we extend the model-specified hazards for outcome and death, and use score statistics to test the null hypothesis that the extensions are unnecessary. Simulated cohort data applied to risk models whose outcome and mortality hazards agreed and disagreed with those generating the data show that the tests are sensitive to poor model fit, provide insight into the reasons for poor fit, and accommodate a wide range of model misspecification. We illustrate the methods by examining the calibration of two breast cancer risk models as applied to a cohort of participants in the Breast Cancer Family Registry. The methods can be implemented using the Risk Model Assessment Program, an R package freely available at http://stanford.edu/~ggong/rmap/.

Attitudes and compliance of clinical management after genetic testing for hereditary breast and ovarian cancer among high-risk Southern Chinese females with breast cancer history

Western studies have shown that the uptake rates of surveillance and prophylaxis may vary among BRCA mutation carriers between ethnicities. The present study is the first to investigate the behavioural impact and subjective attitudes in Southern Chinese high-risk families who had undergone BRCA1 and BRCA2 genetic testing up to 2.5years post-testing. Individuals who had such genetic testing and have consented to participate in the prospective database of Hong Kong Hereditary Breast Cancer Family Registry were recruited and surveyed by a face-to-face or telephone interview. Sociodemographic information, genetic test results, pre- and post-testing surveillance, medical regimes, and attitudes towards the choice of clinical management were obtained by interviews and retrieval of medical records using this prospective database. 69 females with breast cancer history were recruited into the study. Twenty-nine female carriers (15 BRCA1 mutated gene-carriers and 14 BRCA2 mutated gene-carriers) and 40 non-carriers of a BRCA 1/2 mutations were interviewed. The uptake rate of high risk breast screening i.e. clinical breast examination, mammography, and breast MRI is significantly higher among female carriers (48.3%) after knowing genetic testing results than before (p<0.01). A strong significant relationship between any increase or decrease of ovarian ultrasound screening (OS) and genetic status is found (p<.001), with more females did OS and with a higher frequency after knowing genetic testing results among both carriers (22.7%→86.4%) and non-carriers (37.5%→50.0%). Among carriers, very few opted for prophylactic surgeries. The present cohort might see prophylaxis as last resort and would use traditional Chinese medicine in cancer risk management.

Reproductive risk factors and oestrogen/progesterone receptor-negative breast cancer in the Breast Cancer Family Registry.

Background:Oestrogen receptor (ER)- and progesterone receptor (PR)-negative (ER−PR−) breast cancer is associated with poorer prognosis compared with other breast cancer subtypes. High parity has been associated with an increased risk of ER−PR− cancer, but emerging evidence suggests that breastfeeding may reduce this risk. Whether this potential breastfeeding benefit extends to women at high risk of breast cancer remains critical to understand for prevention.Methods:Using population-based ascertained cases (n=4011) and controls (2997) from the Breast Cancer Family Registry, we examined reproductive risk factors in relation to ER and PR status.Results:High parity (⩾3 live births) without breastfeeding was positively associated only with ER−PR− tumours (odds ratio (OR)=1.57, 95% confidence interval (CI), 1.10–2.24); there was no association with parity in women who breastfed (OR=0.93, 95% CI 0.71–1.22). Across all race/ethnicities, associations for ER−PR− cancer were higher among women who did not breastfeed than among women who did. Oral contraceptive (OC) use before 1975 was associated with an increased risk of ER−PR− cancer only (OR=1.32, 95% CI 1.04–1.67). For women who began OC use in 1975 or later there was no increased risk.Conclusions:Our findings support that there are modifiable factors for ER−PR− breast cancer and that breastfeeding in particular may mitigate the increased risk of ER−PR− cancers seen from multiparity.

Oral contraceptive and reproductive risk factors for ovarian cancer within sisters in the breast cancer family registry

Background:Oral contraceptive use has been consistently associated with a reduced risk of ovarian cancer in unrelated, average risk women; however little data exist on whether this benefit extends to higher risk women from cancer families. To examine this, we conducted family-based analyses using the Breast Cancer Family Registry.Methods:We used generalised estimating equations to obtain the population average effect across all families (n=389 cases, n=5643 controls) and conditional logistic regression to examine within-family differences in a subset with at least two sisters discordant on ovarian cancer status (n=109 cases, n=149 unaffected sister controls).Results:In the multivariable generalised estimating equation model there was a reduced risk of ovarian cancer for ever use of oral contraceptives compared with never use (OR=0.58, 95% CI: 0.37, 0.91), and in the conditional logistic model there was a similar inverse association; however, it was not statistically significant (OR=0.52, 95% CI: 0.23, 1.17). We examined this association by BRCA1/2 status and observed a statistically significant reduced risk in the non-carriers only.Conclusion:We observed a decreased risk of ovarian cancer with oral contraceptive use supporting that this association observed in unrelated women extends to related women at higher risk.

Abstract P2-07-03: High-throughput germline mutation screening for hereditary breast cancer in southern Chinese patients by massively parallel DNA sequencing

Abstract Introduction: Breast cancer is the most common malignancy and 3rd leading cause of deaths among the female population in Hong Kong. Since the establishment of The Hong Kong Hereditary Breast Cancer Family Registry in 2007, 1344 patients with breast and/or ovarian cancer who met the selection criteria were recruited for genetic testing in Hong Kong. Since 2011 we started to employ next-generation DNA sequencing (NGS) to expedite the analysis workflow and expand the panel of genes for sequencing. Aim: To evaluate the workflow of NGS in mutation screening of BRCA1, BRCA2, TP53 and PTEN genes, and compared with the sequence data obtained by Sanger sequencing. Methods: We sequenced BRCA1, BRCA2, TP53 and PTEN genes in peripheral blood samples of 410 patients, 53 positive controls and 107 healthy local individuals using 454 GS Junior System. Generation of barcoded amplicon libraries was streamlined by microfluidic PCR using Fluidigm Access Array System. Sequencing data were analyzed by an in-house developed fully automatic bioinformatics pipeline, which mainly consists of GS Amplicon Variant Analyzer, SAMtools and Ensembl Variant Effect Predictor. All putative mutations identified were validated by Sanger sequencing. Furthermore, the frequency of BRCA1, BRCA2 and PTEN missense variants of unknown significance (VUS) identified in the cohort were compared among 107 healthy local individuals and 1000 Genomes project samples. The VUS were also subjected to a panel of in silico prediction methods including PolyPhen and SIFT. Results: Among 410 patients, there were 7 in BRCA1, 6 in BRCA2 and 1 in TP53 mutations found, including 1 novel recurrent BRCA2 (c.7007G&amp;gt;T) and 1 novel founder BRCA2 (c.5164_5165delAG) mutations. Based on multiple criteria, 12 in BRCA1, 12 in BRCA2 and 1 in PTEN VUS could be prioritized for further investigation. The bioinformatics pipeline was extensively evaluated with Sanger-validated controls. The evaluation determined minimum sequencing coverage needed in this sequencing platform for accurate analysis. The pipeline accuracy was demonstrated by successful detecting mutations from 53 positive controls, including single nucleotide variants, insertions and deletions in different sequence context. Conclusion: BRCA1, BRCA2, TP53 and PTEN mutation screening of 410 patients were expedited by high-throughput DNA sequencing. This method could detect 14 positive cases, including recurrent mutations, in a shorter period of time when compared with Sanger full gene sequencing. High-risk patients who are negative for the gene panel may need further investigation other than screening for BRCA1/2. The in-house developed bioinformatics pipeline was validated to detect various types of mutations and potentially become a conventional platform for genetic screening. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-07-03.

Abstract A49: GSTM1, GSTT1, GST polymorphisms, physical activity, and breast cancer risk in premenopausal women of European ancestry

Abstract Background: Susceptibility to premenopausal breast cancer may in part be attributable to inter-individual variability in GST genetic polymorphisms and lifestyle risk factors. Glutathione S-transferase (GST), a family of Phase II detoxification enzymes, may play an important role in breast cancer risk. GSTs are protective through their defense against free radicals and detoxification of toxic compounds, but may also participate in the activation of oxidative metabolites of carcinogenic compounds. Studies have postulated increased susceptibility to cancer in persons with GSTMI or GSTT1 deletions polymorphisms. In particular, inherited homozygous deletions of the GSTM1 and GSTT1 genotype can lead to the absence of enzyme activity, which is associated with increased breast cancer risk. Leisure time physical activity is associated with decreased breast cancer risk any may attenuate oxidative damage in subjects with GSTM1 and GSTT1 deletion genotypes. Hence, physical activity may protect against breast cancer through interaction with specific GST genotypes. We investigated associations between (1) GSTM1 and GSTT1 deletion genes, GST SNPs and premenopausal breast cancer risk; and (2) whether interactions between GST genotype and leisure time physical activity influenced breast cancer risk in women of European Ancestry. Methods: The study design is a population-base case-control study (1476 cases and 699 controls) of premenopausal women (&amp;lt;50 years of age). Study participants were first primary breast cancer cases and unaffected population-based controls recruited through three population-based registries from the Breast Cancer Family Registry. Clinical and epidemiologic data were taken from standardized family history and epidemiology questionnaires. The physical activity questionnaire provided data on the number of hours per week of leisure time exercise during specific age periods through-out life. Lifetime and recent (previous 3 years) physical activity was calculated using a previously described algorithm, which assigned 5.4 and 8.5 METs to moderate and strenuous activities, respectively, and corrected for demographic characteristics affecting MET value of activity. GSTM1 and GSTT1 deletion genes and 14 GST single nucleotide polymorphisms (SNP) were genotyped using TaqMan™real-time PCR technology. Logistic regression analysis was used to estimate odds ratios and corresponding 95% confidence intervals (CI) for associations between premenopausal breast cancer and GST deletion genotypes, GST SNPs and interactions by physical activity. Results: We did not find robust statistically significant associations between the GST deletion genes, GST SNPS and physical activity with premenopausal breast cancer risk. After adjustment, GSTM3 SNP rs1332018 was nominally associated with the ER+/PR+ breast cancer subtype (p&amp;lt;0.05). We found nominally significant interactions between two linked SNPs in the GSTM3 gene, rs7483 (a nonsynonymous SNP) and rs1537234, and level of recent physical activity for women with the ER-/PR- subtype (p&amp;lt;0.01), after adjusting for known risk factors. However these associations were not significant after Bonferroni correction. Conclusion: The observed associations between established GST deletion genotypes, GST SNPs and premenopausal breast cancer in women of European ancestry were not significant after accounting for multiple comparisons. However, results suggest that risk for ER-/PR- premenopausal breast cancer may change depending on level of physical activity in women with one or more GST risk alleles. Given the potential for public health impact, these results support a need for replication studies to confirm or refute these associations. Citation Format: Tanya Agurs-Collins, Edwin S. Iversen, Frank Perna, Bolormaa Baljinnyam. GSTM1, GSTT1, GST polymorphisms, physical activity, and breast cancer risk in premenopausal women of European ancestry. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr A49.

Differences in DNA methylation by extent of breast cancer family history in unaffected women

Breast cancer clusters within families but genetic factors identified to date explain only a portion of this clustering. Lower global DNA methylation in white blood cells (WBC) has been associated with increased breast cancer risk. We examined whether WBC DNA methylation varies by extent of breast cancer family history in unaffected women from high-risk breast cancer families. We evaluated DNA methylation levels in LINE-1, Alu and Sat2 in 333 cancer-free female family members of the New York site of the Breast Cancer Family Registry, the minority of which were known BRCA1 or BRCA2 mutation carriers. We used generalized estimated equation models to test for differences in DNA methylation levels by extent of their breast cancer family history after adjusting for age. All unaffected women had at least one sister affected with breast cancer. LINE-1 and Sat2 DNA methylation levels were lower in individuals with 3 or more (3+) first-degree relatives with breast cancer relative to women with only one first-degree relative. For LINE-1, Alu, and Sat2, having 3+ affected first-degree relatives was associated with a decrease of 23.4% (95%CI = −46.8%, 0.1%), 17.9% (95%CI = −39.5%, 3.7%) and 11.4% (95% CI = −20.3%, −2.5%), respectively, relative to individuals with only one affected first-degree relative, but the results were only statistically significant for Sat2. Individuals having an affected mother had 17.9% lower LINE-1 DNA methylation levels (95% CI = −28.8%, −7.1%) when compared with those not having an affected mother. No associations were observed for Alu or Sat2 by maternal breast cancer status. If replicated, these results indicate that lower global WBC DNA methylation levels in families with extensive cancer histories may be one explanation for the clustering of cancers in these families. Family clustering of disease may reflect epigenetic as well as genetic and shared environmental factors.

Impact of familial risk and mammography screening on prognostic indicators of breast disease among women from the Ontario site of the Breast Cancer Family Registry

Although several studies have found screen-detected cancers in women with familial breast cancer risk have favorable prognostic features compared with symptomatic cancers, the impact of level of familial risk is unknown. A cohort of 899 first-degree female relatives of cases of breast cancer from the Ontario site of the Breast Cancer Family Registry was followed for 2 years. Logistic regression analyses compared diagnoses of breast cancer or benign breast disease (BBD) between women at high (n = 258, 28.7 %) versus low/moderate (n = 641, 71.3 %) familial risk. Similar analyses compared prognostic features of invasive cancers and BBD by level of familial risk and mammography screening status. Among 899 women, 44 (4.9 %) were diagnosed with invasive breast cancer and/or ductal carcinoma in situ, and 56 (6.2 %) with BBD. Women with high familial risk were significantly more likely to be diagnosed with breast cancer [odds ratio (OR) = 2.84, 95 % confidence interval (CI) 1.50-5.38] than low/moderate risk women, particularly if diagnosed at age ≥50 (OR = 2.99, 95 % CI 1.37-6.56) or screened with mammography (OR = 3.33, 95 % CI 1.54-7.18). High risk women were more likely to be diagnosed with BBD (OR = 1.94, 95 % CI 1.03-3.66). Level of familial risk was not associated with prognostic features. Cancers among unscreened women were larger (OR = 9.72, 95 % CI 1.01-93.61) and diagnosed at stage II or above (OR = 7.80, 95 % CI 1.18-51.50) compared with screen-detected cancers. Screening mammography may be effective for women with a first-degree family history of breast cancer, irrespective of level of familial risk.

DNA double-strand break repair genotype and phenotype and breast cancer risk within sisters from the New York site of the Breast Cancer Family Registry (BCFR)

We previously observed that poor DNA repair phenotype is associated with increased breast cancer (BC) risk within families. Here, we examined whether genetic variation in double-strand break repair (DSBR) genes is associated with BC risk and if genotypes are related to phenotype in unaffected women. Using data from the New York site of the Breast Cancer Family Registry, we investigated 25 single-nucleotide polymorphism (SNPs) involved in DSBR using biospecimens from 337 BC cases and 410 unaffected sister controls. Genotypes in XRCC4 were associated with BC risk, with ORs of 1.67 (95 % CI 1.01-2.76) for the combined GA/AA of rs1805377 and 1.69 (95 % CI 1.03-2.77) for rs1056503 TG/GG; these associations were no longer statistically significant in multivariable conditional logistic regression models. When examining the association of SNPs with phenotype, we found that genotypes of XRCC5 rs3834 and rs1051685, which were highly correlated with each other, were associated with end-joining (EJ) capacity; women with the XRCC5 rs3834 GA genotype had better DNA repair as measured by higher levels of EJ capacity (37.8 ± 14.1 % for GA vs. 27.9 ± 11.8 % for GG carriers p = 0.0006). Women with the AA genotype of BRCA1 rs799917 also had higher EJ capacity (35.1 ± 9.2 %) than those with GG (26.4 ± 10.1 %, p = 0.02). Overall, we found that selected DSBR genotypes were associated with phenotype, although they were not associated with BC risk itself, suggesting that phenotypic measures are influenced by endogenous and exogenous factors across the life course and may be better markers than genotypic measures for ascertaining BC risk.

Diagnostic Chest X-Rays and Breast Cancer Risk before Age 50 Years for BRCA1 and BRCA2 Mutation Carriers

The effects of low-dose medical radiation on breast cancer risk are uncertain, and few studies have included genetically susceptible women, such as those who carry germline BRCA1 and BRCA2 mutations. We studied 454 BRCA1 and 273 BRCA2 mutation carriers ages younger than 50 years from three breast cancer family registries in the United States, Canada, and Australia/New Zealand. We estimated breast cancer risk associated with diagnostic chest X-rays by comparing mutation carriers with breast cancer (cases) with those without breast cancer (controls). Exposure to chest X-rays was self-reported. Mammograms were not considered in the analysis. After adjusting for known risk factors for breast cancer, the ORs for a history of diagnostic chest X-rays, excluding those for tuberculosis or pneumonia, were 1.16 [95% confidence interval (CI), 0.64-2.11] for BRCA1 mutations carriers and 1.22 (95% CI, 0.62-2.42) for BRCA2 mutations carriers. The OR was statistically elevated for BRCA2 mutation carriers with three to five diagnostic chest X-rays (P = 0.01) but not for those with six or more chest X-rays. Few women reported chest fluoroscopy for tuberculosis or chest X-rays for pneumonia; the OR estimates were elevated, but not statistically significant, for BRCA1 mutation carriers. Our findings do not support a positive association between diagnostic chest X-rays and breast cancer risk before the ages of 50 years for BRCA1 or BRCA2 mutation carriers. Given the increasing use of diagnostic imaging involving higher ionizing radiation doses, further studies of genetically predisposed women are warranted.

Prospective validation of the breast cancer risk prediction model BOADICEA and a batch-mode version BOADICEACentre

Background:Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) is a risk prediction algorithm that can be used to compute estimates of age-specific risk of breast cancer. It is uncertain whether BOADICEA performs adequately for populations outside the United Kingdom.Methods:Using a batch mode version of BOADICEA that we developed (BOADICEACentre), we calculated the cumulative 10-year invasive breast cancer risk for 4176 Australian women of European ancestry unaffected at baseline from 1601 case and control families in the Australian Breast Cancer Family Registry. Based on 115 incident breast cancers, we investigated calibration, discrimination (using receiver-operating characteristic (ROC) curves) and accuracy at the individual level.Results:The ratio of expected to observed number of breast cancers was 0.92 (95% confidence interval (CI) 0.76–1.10). The E/O ratios by subgroups of the participant's relationship to the index case and by the reported number of affected relatives ranged between 0.83 and 0.98 and all 95% CIs included 1.00. The area under the ROC curve was 0.70 (95% CI 0.66–0.75) and there was no evidence of systematic under- or over-dispersion (P=0.2).Conclusion:BOADICEA is well calibrated for Australian women, and had good discrimination and accuracy at the individual level.

Tamoxifen and Risk of Contralateral Breast Cancer for BRCA1 and BRCA2 Mutation Carriers

To determine whether adjuvant tamoxifen treatment for breast cancer (BC) is associated with reduced contralateral breast cancer (CBC) risk for BRCA1 and/or BRCA2 mutation carriers. Analysis of pooled observational cohort data, self-reported at enrollment and at follow-up from the International BRCA1, and BRCA2 Carrier Cohort Study, Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer, and Breast Cancer Family Registry. Eligible women were BRCA1 and BRCA2 mutation carriers diagnosed with unilateral BC since 1970 and no other invasive cancer or tamoxifen use before first BC. Hazard ratios (HRs) for CBC associated with tamoxifen use were estimated using Cox regression, adjusting for year and age of diagnosis, country, and bilateral oophorectomy and censoring at contralateral mastectomy, death, or loss to follow-up. Of 1,583 BRCA1 and 881 BRCA2 mutation carriers, 383 (24%) and 454 (52%), respectively, took tamoxifen after first BC diagnosis. There were 520 CBCs over 20,104 person-years of observation. The adjusted HR estimates were 0.38 (95% CI, 0.27 to 0.55) and 0.33 (95% CI, 0.22 to 0.50) for BRCA1 and BRCA2 mutation carriers, respectively. After left truncating at recruitment to the cohort, adjusted HR estimates were 0.58 (95% CI, 0.29 to 1.13) and 0.48 (95% CI, 0.22 to 1.05) based on 657 BRCA1 and 426 BRCA2 mutation carriers with 100 CBCs over 4,392 person-years of prospective follow-up. HRs did not differ by estrogen receptor status of the first BC (missing for 56% of cases). This study provides evidence that tamoxifen use is associated with a reduction in CBC risk for BRCA1 and BRCA2 mutation carriers. Further follow-up of these cohorts will provide increased statistical power for future prospective analyses.

Accuracy of Self-Reported Screening Mammography Use: Examining Recall among Female Relatives from the Ontario Site of the Breast Cancer Family Registry

Evidence of the accuracy of self-reported mammography use among women with familial breast cancer risk is limited. This study examined the accuracy of self-reported screening mammography dates in a cohort of 1,114 female relatives of breast cancer cases, aged 26 to 73 from the Ontario site of the Breast Cancer Family Registry. Self-reported dates were compared to dates abstracted from imaging reports. Associations between inaccurate recall and subject characteristics were assessed using multinomial regression. Almost all women (95.2% at baseline, 98.5% at year 1, 99.8% at year 2) accurately reported their mammogram use within the previous 12 months. Women at low familial risk (OR = 1.77, 95% CI: 1.00–3.13), who reported 1 or fewer annual visits to a health professional (OR = 1.97, 95% CI: 1.15, 3.39), exhibited a lower perceived breast cancer risk (OR = 1.90, 95% CI: 1.15, 3.15), and reported a mammogram date more than 12 months previous (OR = 5.22, 95% CI: 3.10, 8.80), were significantly more likely to inaccurately recall their mammogram date. Women with varying levels of familial risk are accurate reporters of their mammogram use. These results present the first evidence of self-reported mammography recall accuracy among women with varying levels of familial risk.

Using SNP genotypes to improve the discrimination of a simple breast cancer risk prediction model

It has been shown that, for women aged 50years or older, the discriminatory accuracy of the Breast Cancer Risk Prediction Tool (BCRAT) can be modestly improved by the inclusion of information on common single nucleotide polymorphisms (SNPs) that are associated with increased breast cancer risk. We aimed to determine whether a similar improvement is seen for earlier onset disease. We used the Australian Breast Cancer Family Registry to study a population-based sample of 962 cases aged 35-59years, and 463 controls frequency matched for age and for whom genotyping data was available. Overall, the inclusion of data on seven SNPs improved the area under the receiver operating characteristic curve (AUC) from 0.58 (95% confidence interval [CI] 0.55-0.61) for BCRAT alone to 0.61 (95% CI 0.58-0.64) for BCRAT and SNP data combined (p<0.001). For women aged 35-39years at interview, the corresponding improvement in AUC was from 0.61 (95% CI 0.56-0.66) to 0.65 (95% CI 0.60-0.70; p=0.03), while for women aged 40-49years at diagnosis, the AUC improved from 0.61 (95% CI 0.55-0.66) to 0.63 (95% CI 0.57-0.69; p=0.04). Using previously used classifications of low, intermediate and high risk, 2.1% of cases and none of the controls aged 35-39years, and 10.9% of cases and 4.0% of controls aged 40-49years were classified into a higher risk group. Including information on seven SNPs associated with breast cancer risk, improves the discriminatory accuracy of BCRAT for women aged 35-39years and 40-49years. Given, the low absolute risk for women in these age groups, only a small proportion are reclassified into a higher category for predicted 5-year risk of breast cancer.

Mammographic density and breast cancer: a comparison of related and unrelated controls in the Breast Cancer Family Registry

IntroductionPercent mammographic density (PMD) is a strong and highly heritable risk factor for breast cancer. Studies of the role of PMD in familial breast cancer may require controls, such as the sisters of cases, selected from the same 'risk set' as the cases. The use of sister controls would allow control for factors that have been shown to influence risk of breast cancer such as race/ethnicity, socioeconomic status and a family history of breast cancer, but may introduce 'overmatching' and attenuate case-control differences in PMD.MethodsTo examine the potential effects of using sister controls rather than unrelated controls in a case-control study, we examined PMD in triplets, each comprised of a case with invasive breast cancer, an unaffected full sister control, and an unaffected unrelated control. Both controls were matched to cases on age at mammogram. Total breast area and dense area in the mammogram were measured in the unaffected breast of cases and a randomly selected breast in controls, and the non-dense area and PMD calculated from these measurements.ResultsThe mean difference in PMD between cases and controls, and the standard deviation (SD) of the difference, were slightly less for sister controls (4.2% (SD = 20.0)) than for unrelated controls (4.9% (SD = 25.7)). We found statistically significant correlations in PMD between cases (n = 228) and sister controls (n = 228) (r = 0.39 (95% CI: 0.28, 0.50; P <0.0001)), but not between cases and unrelated controls (n = 228) (r = 0.04 (95% CI: -0.09, 0.17; P = 0.51)). After adjusting for other risk factors, square root transformed PMD was associated with an increased risk of breast cancer when comparing cases to sister controls (adjusted odds ratio (inter-quintile odds ratio (IQOR) = 2.19, 95% CI = 1.20, 4.00) or to unrelated controls (adjusted IQOR = 2.62, 95% CI = 1.62, 4.25).ConclusionsThe use of sister controls in case-control studies of PMD resulted in a modest attenuation of case-control differences and risk estimates, but showed a statistically significant association with risk and allowed control for race/ethnicity, socioeconomic status and family history.

Decreased TGFBR1 signaling and breast cancer.

1548 Background: We previously identified TGFBR1*6A (rs11466445), a hypomorphic TGF-beta type 1 receptor variant that is associated with cancer risk, has impaired TGF-beta signaling capability, and enhances the migration and invasion of breast cancer cells (Cancer Res 2008, 68:1319). Two recent large meta-analyses of case control studies have found a significant association between TGFBR1*6A and risk of breast cancer (Mol Biol Rep 2010 37:3227; PLoS One 2012,7(8). Rs7034462 is a single nucleotide polymorphism (SNP) in a noncoding region more than 9 kilobases upstream of TGFBR1 exon 1, which has been shown to be associated with decreased TGFBR1 expression similar to TGFBR1*6A (J Exp Clin Cancer Res 2010, 29:57). In this study we tested the hypothesis that rs7034462 may be associated with breast cancer risk. Methods: rs7034462 was genotyped in DNA obtained from patients with breast cancer and their unaffected sisters recruited by the Breast Cancer Family Registry (B-CFR). Results: The median age of cases and controls was 48.8 and 47.6 years, respectively. Using a simple case-control genetic association analysis for this family-matched population, rs7034462 was found to be associated with breast cancer risk. Conclusions: TGFBR1 rs7034462 is emerging as a low penetrance breast cancer susceptibility allele suggesting that two distinct TGFBR1 SNPs, each associated with decreased TGFBR1 expression, may modulate breast cancer risk. [Table: see text]

Risk of Pancreatic Cancer in Breast Cancer Families from the Breast Cancer Family Registry

Increased risk of pancreatic cancer has been reported in breast cancer families carrying BRCA1and BRCA2 mutations; however, pancreatic cancer risk in mutation-negative (BRCAX) families has not been explored to date. The aim of this study was to estimate pancreatic cancer risk in high-risk breast cancer families according to the BRCA mutation status. A retrospective cohort analysis was applied to estimate standardized incidence ratios (SIR) for pancreatic cancer. A total of 5,799 families with ≥1 breast cancer case tested for mutations in BRCA1 and/or BRCA2 were eligible. Families were divided into four classes: BRCA1, BRCA2, BRCAX with ≥2 breast cancer diagnosed before age 50 (class 3), and the remaining BRCAX families (class 4). BRCA1 mutation carriers were at increased risk of pancreatic cancer [SIR = 4.11; 95% confidence interval (CI), 2.94-5.76] as were BRCA2 mutation carriers (SIR = 5.79; 95% CI, 4.28-7.84). BRCAX family members were also at increased pancreatic cancer risk, which did not appear to vary by number of members with early-onset breast cancer (SIR = 1.31; 95% CI, 1.06-1.63 for class 3 and SIR = 1.30; 95% CI, 1.13-1.49 for class 4). Germline mutations in BRCA1 and BRCA2 are associated with an increased risk of pancreatic cancer. Members of BRCAX families are also at increased risk of pancreatic cancer, pointing to the existence of other genetic factors that increase the risk of both pancreatic cancer and breast cancer. This study clarifies the relationship between familial breast cancer and pancreatic cancer. Given its high mortality, pancreatic cancer should be included in risk assessment in familial breast cancer counseling.