Genetic testing in an ethnically diverse cohort of high-risk women: a comparative analysis of BRCA1 and BRCA2 mutations in American families of European and African ancestry

Differences in reproductive risk factors for breast cancer in middle-aged women in Marin County, California and a sociodemographically similar area of Northern California

Background

The Northern California county of Marin (MC) has historically had high breast cancer incidence rates. Because of MC's high socioeconomic status (SES) and racial homogeneity (non-Hispanic White), it has been difficult to assess whether these elevated rates result from a combination of established risk factors or other behavioral or environmental factors. This survey was designed to compare potential breast cancer risks and incidence rates for a sample of middle-aged MC women with those of a demographically similar population.

Methods

A random sample of 1500 middle-aged female members of a large Northern California health plan, half from Marin County (MC) and half from a comparison area in East/Central Contra Costa County (ECCC), were mailed a survey covering family history, reproductive history, use of oral contraceptives (OC) and hormone replacement therapy (HRT), behavioral health risks, recency of breast screening, and demographic characteristics. Weighted data were used to compare prevalence of individual breast cancer risk factors and Gail scores. Age-adjusted cumulative breast cancer incidence rates (2000–2004) were also calculated for female health plan members aged 40–64 residing in the two geographic areas.

Results

Survey response was 57.1% (n = 427) and 47.9% (n = 359) for MC and ECCC samples, respectively. Women in the two areas were similar in SES, race, obesity, exercise frequency, current smoking, ever use of OCs and HRT, age at onset of menarche, high mammography rates, family history of breast cancer, and Gail scores. However, MC women were significantly more likely than ECCC women to be former smokers (43.6% vs. 31.2%), have Ashkenazi Jewish heritage (12.8% vs. 7.1%), have no live births before age 30 (52.7% vs. 40.8%), and be nulliparous (29.2% vs. 15.4%), and less likely to never or rarely consume alcohol (34.4% vs. 41.9%). MC and ECCC women had comparable 2000–2004 invasive breast cancer incidence rates.

Conclusion

The effects of reproductive risks factors, Ashkenazi Jewish heritage, smoking history, and alcohol consumption with regard to breast cancer risk in Marin County should be further evaluated. When possible, future comparisons of breast cancer incidence rates between regions should adjust for differences in income and education in addition to age and race/ethnicity, preferably by using a sociodemographically similar comparison group.

Prediction of BRCA Mutations Using the BRCAPRO Model in Clinic-Based African American, Hispanic, and Other Minority Families in the United States

PURPOSE

BRCAPRO, a BRCA mutation carrier prediction model, was developed on the basis of studies in individuals of Ashkenazi Jewish and European ancestry. We evaluated the performance of the BRCAPRO model among clinic-based minority families. We also assessed the clinical utility of mutation status of probands (the first individual tested in a family) in the recommendation of BRCA mutation testing for other at-risk family members.

PATIENTS AND METHODS

A total of 292 minority families with at least one member who was tested for BRCA mutations were identified through the Breast Cancer Family Registry and the University of Chicago. Using the BRCAPRO model, the predicted likelihood of carrying BRCA mutations was generated. Area under the receiver operating characteristic curves (AUCs) were calculated.

RESULTS

There were 104 African American, 130 Hispanic, 37 Asian-American, and 21 other minority families. The AUC was 0.748 (95% CI, 0.672 to 0.823) for all minorities combined. There was a statistically nonsignificant trend for BRCAPRO to perform better in Hispanic families than in other minority families. After taking into account the mutation status of probands, BRCAPRO performance in additional tested family members was improved: the AUC increased from 0.760 to 0.902.

CONCLUSION

The findings support the use of BRCAPRO in pretest BRCA mutation prediction among minority families in clinical settings, but there is room for improvement in ethnic groups other than Hispanics. Knowledge of the mutation status of the proband provides additional predictive value, which may guide genetic counselors in recommending BRCA testing of additional relatives when a proband has tested negative.

Breast cancer incidence and mortality in a Caribbean population: comparisons with African-Americans

We describe breast cancer incidence and mortality in the predominantly African-origin population of Barbados, which shares an ancestral origin with African-Americans. Age-standardized incidence rates were calculated from histologically confirmed breast cancer cases identified during a 45-month period (July 2002-March 2006). Mortality rates were estimated from death registrations over 10-years starting January 1995. There were 396 incident cases of breast cancer for an incidence rate of 78.1 (95% confidence interval (CI) 70.5-86.3), standardized to the US population. Breast cancer incidence in African-Americans between 2000 and 2004 was 143.7 (142.0-145.5) per 100,000. Incidence peaked at 226.6 (174.5-289.4) per 100,000 among Barbadian women aged 50-54 years, and declined thereafter, a pattern in marked contrast to trends in African-American women, whose rates continued to increase to a peak of 483.5 per 100,000 in those aged 75-79 years. Incidence rate ratios comparing Barbadian and African-American women showed no statistically significant differences among women aged>or=55 years (p Collapse

Key Words

• breast cancer
• african-origin
• incidence
• mortality

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MESH Headings

• Adolescent
• Adult
• Black or African American
• Aged
• Aged, 80 and over
• Black People
• Breast Neoplasms/epidemiology
• Breast Neoplasms/ethnology
• Breast Neoplasms/mortality
• Caribbean Region
• Child
• Child, Preschool
• Female
• Humans
• Incidence
• Infant
• Infant, Newborn
• Middle Aged
• Risk

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Grants

• R01 CA114379 NCI NIH HHS

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Affiliation(s)

Anselm J Hennis Chronic Disease Research Centre, The University of the West Indies, Bridgetown, Barbados, West Indies.
Ian R Hambleton
Suh-Yuh Wu
Maria Cristina Leske
Barbara Nemesure
Barbados National Cancer Study Group

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Collaborators

M Cristina Leske, Barbara Nemesure, Suh-Yuh Wu, Karen Kelleher, Melinda Santoro, Anselm Hennis, Celia Greaves, Lynda Williams, Ingrid Cumberbatch, Karen Archer, Karen Bynoe, Nastassia Rambarran, Rachel Harris, Patricia Basdeo, Pissamai Maul, Wendy Browne, Shirley Reeves, Janelle Springer, Mauretta Newton, Lyndon Waterman, Andrew Stoute, Ronald Worrell, Carl Walters, Ray Scott, John Carpten, Jeffrey Trent, Joan Bailey-Wilson, Gita Sharma, Agnes Baffoe-Bonnie, Louise Brinton, Olufunmilayo Olopade, Tim Rebbeck, Duncan Thomas, Trevor A Hassell, Henry Fraser, Beverley Barnett, Jerry Emtage, Selwyn Ferdinand, W Leroy Inniss, Timothy Roach, Beverley Miller,

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Hereditary breast and ovarian cancer syndrome : the impact of race on uptake of genetic counseling and testing

Breast cancer is a significant cause of morbidity and mortality in the United States. Although breast cancer is more common among White American (WA) women, incidence rates are higher among young African American (AA) women. Approximately 5-10% of all breast cancer can be accounted for by germline mutations in the breast cancer (BRCA)1 and BRCA2 genes responsible for hereditary breast and ovarian cancer (HBOC) syndrome. Although genetic counseling (GC) and genetic testing (GT) for HBOC have become widely accepted by the WA population, cancer genetic services are underused among AA. Many investigators have evaluated a wide spectrum of BRCA1 and BRCA2 mutations in the AA and African population with the possible identification of African founder mutations. Barriers to GC and GT include lack of knowledge and/or negative attitudes regarding genetics and genetics research, and concerns regarding the potential for racial discrimination. It is important for future research to focus on ways in which to eliminate barriers to GC and GT to alleviate disparity in the use of genetic services among high-risk AA women.

BRCA1/2 in high-risk African American women with breast cancer: providing genetic testing through various recruitment strategies

BACKGROUND

Due to the disproportionate numbers of African American women affected with early onset breast cancer, we sought to investigate mutation frequency of BRCA1 and BRCA2 (BRCA1/2) in a sample of African American women, recruited through a variety of methods.

METHODS

We conducted a study investigating BRCA1/2 among 51 African American breast cancer patients with a personal or family history suggestive of hereditary predisposition to breast cancer. All individuals underwent genetic counseling and BRCA1/2 mutation analysis, through protein-truncation test on exon 11 of BRCA1 and exons 10 and 11 of BRCA2, which together account for approximately 50% of mutations observed within these genes.

RESULTS

Of the 51 women tested for BRCA1/2 mutations, 3 were identified as mutation carriers (5.9%), including 1 in BRCA1 and 2 in BRCA2. Recruitment strategies varied and included physician referrals from the Moffitt Cancer Center Breast Program (18), community-based oncologists (13), primary care physicians (3), newspaper advertisements and brochures (5), community or support group referrals (7), self/family referral through word of mouth (2), and the Florida State Cancer Registry (3).

CONCLUSIONS

Our results suggest that (1) BRCA1/2 mutations are seen in high-risk African American women with breast cancer, and (2) strategies for recruitment of African American women in studies of genetic testing for breast cancer genes have varied levels of success. Our study highlights the need for further studies in this population group.

Performance of BRCA1/2 mutation prediction models in Asian Americans

PURPOSE

There are established differences in breast cancer epidemiology between Asian and white individuals, but little is known about hereditary breast cancer in Asian populations. Although increasing numbers of Asian individuals are clinically tested for BRCA1/2 mutations, it is not known whether computer models that predict mutations work accurately in Asian individuals. We compared the performance in Asian and white individuals of two widely used BRCA1/2 mutation prediction models, BRCAPRO and Myriad II.

PATIENTS AND METHODS

We evaluated BRCAPRO and Myriad II in 200 Asian individuals and a matched control group of 200 white individuals who were tested for BRCA1/2 mutations at four cancer genetics clinics, by comparing numbers of observed versus predicted mutation carriers and by evaluating area under the receiver operating characteristic curve (AUC) for each model.

RESULTS

BRCAPRO and Myriad II accurately predicted the number of white BRCA1/2 mutation carriers (25 observed v 24 predicted by BRCAPRO; 25 predicted by Myriad II, P > or = .69), but underpredicted Asian carriers by two-fold (49 observed v 25 predicted by BRCAPRO; 26 predicted by Myriad II; P < or = 3 x 10(-7)). For BRCAPRO, this racial difference reflects substantial underprediction of Asian BRCA2 mutation carriers (26 observed v 4 predicted; P = 1 x 10(-30)); for Myriad II, separate mutation predictions were not available. For both models, AUCs were nonsignificantly lower in Asian than white individuals, suggesting less accurate discrimination between Asian carriers and noncarriers.

CONCLUSION

Both BRCAPRO and Myriad II underestimated the proportion of BRCA1/2 mutation carriers, and discriminated carriers from noncarriers less well, in Asian compared with white individuals.

The relative contribution of point mutations and genomic rearrangements in BRCA1 and BRCA2 in high-risk breast cancer families

The demand for BRCA1 and BRCA2 mutation screening is increasing as their identification will affect medical management. However, both the contribution of different mutation types in BRCA1 and BRCA2 and whom should be offered testing for large genomic rearrangements have not been well established in the U.S. high-risk population. We define the prevalence and spectrum of point mutations and genomic rearrangements in BRCA genes in a large U.S. high-risk clinic population of both non-Ashkenazi and Ashkenazi Jewish descent, using a sample set representative of the U.S. genetic testing population. Two hundred fifty-one probands ascertained through the University of Pennsylvania high-risk clinic, all with commercial testing for BRCA1 and BRCA2, with an estimated prevalence of BRCA mutation >or=10% using the Myriad II model and a DNA sample available, were studied. Individuals without deleterious point mutations were screened for genomic rearrangements in BRCA1 and BRCA2. In the 136 non-Ashkenazi Jewish probands, 36 (26%) BRCA point mutations and 8 (6%) genomic rearrangements (7 in BRCA1 and 1 in BRCA2) were identified. Forty-seven of the 115 (40%) Ashkenazi Jewish probands had point mutations; no genomic rearrangements were identified in the group without mutations. In the non-Ashkenazi Jewish probands, genomic rearrangements constituted 18% of all identified BRCA mutations; estimated mutation prevalence (Myriad II model) was not predictive of their presence. Whereas these findings should be confirmed in larger sample sets, our data suggest that genomic rearrangement testing be considered in all non-Ashkenazi Jewish women with an estimated mutation prevalence >or=10%.

Population differences in breast cancer severity

Breast cancer incidence and mortality vary among different populations. African-American, Hispanic, Asian and Native American women have lower incidence but higher mortality compared with non-Hispanic white women. Explanations for the observed variation include social and economic factors such as education, income level, health insurance coverage, use of mammography, parity, breastfeeding and diet. Breast cancer may be a heterogeneous disease with different subtypes of tumors having different genetic and environmental risk factors. The difference in frequency of particular tumor subtypes between populations may explain some of the differences in incidence and mortality. Known genetic variants explain a small fraction of breast cancer cases, and so far there are no susceptibility genes that explain population differences in incidence and mortality. Studies evaluating the risk for particular tumor subtypes combining genetic and environmental variables and analyzing cases from different populations are needed to understand population differences in the severity of breast cancer.

Strategies and stakeholders: minority recruitment in cancer genetics research

The Cancer Genetics Network (CGN) is one of a growing number of large-scale registries designed to facilitate investigation of genetic and environmental contributions to health and disease. Despite compelling scientific and social justice arguments that recommend diverse participation in biomedical research, members of ethnic minority groups continue to be chronically underrepresented in such projects. The CGN studies reported in this issue used strategies well documented to increase minority participation in research activities, including use of community-targeted materials, addressing community trust concerns, and the adoption of personalized and flexible research protocols. Here, we review the outcome of these efforts to increase minority recruitment to the CGN, and ask what lessons the findings suggest for future minority recruitment initiatives.

BRCA1 and BRCA2 risk perceptions among African American women at increased risk for hereditary breast-ovarian cancer

OBJECTIVES

To describe BRCA1 or BRCA2 (BRCA1/2) risk perceptions among African American women at increased risk for hereditary breast-ovarian cancer and to identify factors having independent associations with these perceptions.

METHODS

Risk perceptions were evaluated by self-report during a structured telephone interview among African American women (n = 162) at increased risk for hereditary cancer who were recruited from oncology clinics, general medical practices, and community oncology resources.

RESULTS

The majority of women (75%) believed that it was likely that they had a BRCA1/2 mutation. Women ages 50 and younger and those with greater cancer-specific worry were most likely to believe that they had a BRCA1/2 mutation.

CONCLUSIONS

Although BRCA1/2 risk perceptions may be consistent with objective risk levels among African American women, discussion about the basis of risk perceptions may enhance provision of genetic counseling and testing in this population.

Retention of African American women in cancer genetics research

Although retention is a critical component of longitudinal cancer genetics research, limited empirical data are available on predictors of study retention among populations that are difficult to enroll. We evaluated predictors of retention in cancer genetics research among African American women at increased risk for having a BRCA1 and BRCA2 (BRCA1/2) mutation. Participants were African American women (n = 192) at increased risk for hereditary breast-ovarian cancer who were enrolled in a longitudinal genetic counseling research study. Retention was evaluated separately for the 1- and 6-month follow-ups and in terms of overall retention (e.g., completion of both telephone interviews). Seventy-three percent of women and 65% of women were retained at the 1- and 6-month follow-ups respectively; in terms of overall retention, 60% of women were retained in both follow-up telephone interviews. Predictors of retention at 1-month included being employed (OR = 2.47, 95% CI = 1.24, 4.93, P = 0.01) whereas predictors of overall retention included having a personal history of breast and/or ovarian cancer (OR = 2.06, 95% CI = 1.07, 3.95, P = 0.03) and having completed genetic counseling (OR = 2.63, 95% CI = 1.39, 4.98, P = 0.003). These data suggest that once enrolled in genetic counseling research, the majority of African American women will continue to participate, especially if concrete clinical services are provided.

Early onset of breast cancer in a group of British black women

Since there are no published data on breast cancer in British black women, we sought to determine whether, like African-American women, they present at a younger age with biologically distinct disease patterns. The method involved a retrospective review of breast cancer to compare age distributions and clinicopathological features between black women and white women in the UK, while controlling for socioeconomic status. All women presented with invasive breast cancer, between 1994 and 2005, to a single East London hospital. Black patients presented significantly younger (median age of 46 years), than white patients (median age of 67 years (P=0.001)). No significant differences between black and white population structures were identified. Black women had a higher frequency of grade 3 tumours, lymph node-positive disease, negative oestrogen receptor and progesterone receptor status and basal-like (triple negative status) tumours. There were no differences in stage at presentation; however, for tumours of < or =2 cm, black patients had poorer survival than white patients (HR=2.90, 95% CI 0.98-8.60, P=0.05). Black women presented, on average, 21 years younger than white women. Tumours in younger women were considerably more aggressive in the black population, more likely to be basal-like, and among women with smaller tumours, black women were more than twice as likely to die of their disease. There were no disparities in socioeconomic status or treatment received. Our findings could have major implications for the biology of breast cancer and the detection and treatment of the disease in black women.

Breast cancer risk associated with BRCA1 and BRCA2 in diverse populations

Germline mutations in the BRCA1 or BRCA2 tumour-suppressor genes are strong predictors of breast and/or ovarian cancer development. The contribution of these mutations to breast cancer risk within any specific population is a function of both their prevalence and their penetrance. Mutation prevalence varies among ethnic groups and may be influenced by founder mutations. Penetrance can be influenced by mutation-specific phenotypes and the potential modifying effects of the patient's own genetic and environmental background. Although estimates of both mutation prevalence and mutation penetrance rates are inconsistent and occasionally controversial, understanding them is crucial for providing accurate risk information to each patient.

Factors influencing perceptions of breast cancer genetic counseling among women in an urban health care system

The study assessed perceptions of breast cancer genetic counseling. Focus groups were conducted with twenty women (ages < = 50 years) in a Midwestern, urban health system identified as at above average risk of developing hereditary breast cancer and referred for breast cancer genetic counseling following mammography. All participants associated the words "breast cancer" with fear. African American women who received breast cancer genetic counseling may have channeled their fear into increased vigilance related to breast health. African American women who did not receive breast cancer genetic counseling were most knowledgeable about it. In contrast, Caucasian women who did not receive it reported uncertainty about the role of genetic counseling and testing in assessing breast cancer risk, mistrust in medical professionals, and lack of trust in the accuracy of genetic tests. The results could be used to help develop interventions to improve informed decision-making regarding breast cancer genetic counseling.

BRCA1 and BRCA2 genetic testing in Hispanic patients: mutation prevalence and evaluation of the BRCAPRO risk assessment model

PURPOSE

The BRCAPRO model, used to predict a family's likelihood of carrying a BRCA1 or BRCA2 mutation, was designed using mutation frequencies of white and Ashkenazi Jewish populations, and may not be applicable to other populations. BRCAPRO was recently validated in African Americans, although has yet to be examined in Hispanics. This retrospective study reports the mutation frequency and spectrum of BRCA1 and BRCA2 mutations in a Hispanic population and evaluates the BRCAPRO model in Hispanics.

PATIENTS AND METHODS

A descriptive analysis of mutation frequency and spectrum was performed for Hispanic patients who underwent BRCA1 and BRCA2 genetic testing at a single institution. For comparative analysis of the BRCAPRO risk model, Hispanic patients who underwent comprehensive analysis were compared with white controls using area under the receiver operating characteristic curves (AUROC).

RESULTS

Fourteen Hispanic individuals who underwent comprehensive analysis were identified to carry a mutation in BRCA1 or BRCA2 (17.9%; 95% CI, 10.2% to 28.3%) and seven individuals had a variant of uncertain significance (9.0%; 95% CI, 12.0% to 30.8%). A total of eight different mutations and three variants were observed within the entire Hispanic population. When evaluating the performance of the BRCAPRO model, the AUROC for Hispanics was 0.774 (95% CI, 0.63 to 0.90), compared with the AUROC of 0.770 (95% CI, 0.65 to 0.89) for whites.

CONCLUSION

Deleterious BRCA1 and BRCA2 mutations occur at considerable frequency within the Hispanic population, many of which have been identified previously in other ethnic populations. The BRCAPRO model appears to perform equally well in Hispanics as in whites.

Triple negative breast carcinoma and the basal phenotype: from expression profiling to clinical practice

Triple negative breast carcinomas (TNBCs) are a group of primary breast tumors with aggressive clinical behavior. Most TNBCs possess a basal phenotype (BP) and show varying degrees of basal cytokeratin and myoepithelial marker expression. The importance of recognizing these tumors came to light largely as the result of gene expression profiling studies that categorized breast cancer into 3 major groups. Two of these groups are defined by their respective expression of estrogen receptor and HER2. TNBCs represent a third group and are defined by negativity for hormone receptors and HER2. TNBCs currently lack effective targeted therapies and are frequently resistant to standard chemotherapeutic regimens. These tumors tend to occur in premenopausal women and members of specific ethnic groups and a subset are associated with heritable BRCA1 mutations. For patients with sporadic TNBCs and BP tumors, BRCA1 dysfunction seems to play a major role in the development and progression of disease. The pathologist's role in the diagnosis and characterization of TNBCs and BP tumors is currently being defined as we are acquiring knowledge of the biologic and genetic underpinnings that drive this heterogeneous group of diseases. This review will provide a historical prospective on TNBCs and tumors that express basal cytokeratins and myoepithelial makers. Additionally, we will discuss the molecular biologic, genetic and pathologic aspects of these tumors. Guidelines will be provided on how to best approach the diagnosis of these cases and on what input pathologists should provide clinicians to help develop optimal therapeutic and preventative strategies against this aggressive group of breast cancers.

Validity of models for predicting BRCA1 and BRCA2 mutations

BACKGROUND

Deleterious mutations of the BRCA1 and BRCA2 genes confer susceptibility to breast and ovarian cancer. At least 7 models for estimating the probabilities of having a mutation are used widely in clinical and scientific activities; however, the merits and limitations of these models are not fully understood.

OBJECTIVE

To systematically quantify the accuracy of the following publicly available models to predict mutation carrier status: BRCAPRO, family history assessment tool, Finnish, Myriad, National Cancer Institute, University of Pennsylvania, and Yale University.

DESIGN

Cross-sectional validation study, using model predictions and BRCA1 or BRCA2 mutation status of patients different from those used to develop the models.

SETTING

Multicenter study across Cancer Genetics Network participating centers.

PATIENTS

3 population-based samples of participants in research studies and 8 samples from genetic counseling clinics.

MEASUREMENTS

Discrimination between individuals testing positive for a mutation in BRCA1 or BRCA2 from those testing negative, as measured by the c-statistic, and sensitivity and specificity of model predictions.

RESULTS

The 7 models differ in their predictions. The better-performing models have a c-statistic around 80%. BRCAPRO has the largest c-statistic overall and in all but 2 patient subgroups, although the margin over other models is narrow in many strata. Outside of high-risk populations, all models have high false-negative and false-positive rates across a range of probability thresholds used to refer for mutation testing.

LIMITATION

Three recently published models were not included.

CONCLUSIONS

All models identify women who probably carry a deleterious mutation of BRCA1 or BRCA2 with adequate discrimination to support individualized genetic counseling, although discrimination varies across models and populations.

The prevalence of BRCA1 and BRCA2 germline mutations in high-risk breast cancer patients of Chinese Han nationality: two recurrent mutations were identified

To have an overview of the role of BRCA1 and BRCA2 genes among Chinese high-risk breast cancer patients, we analyzed 489 such high-risk breast cancer patients from four breast disease clinical centers in China, by using PCR-DHPLC or SSCP-DNA sequencing analysis. Allelotype analysis was done at five short tandem repeat (STR) markers in or adjacent to BRCA1 on the recurrent mutation carriers. For those analyzed both genes, 8.7% of early-onset breast cancer cases and 12.9% of familial breast cancer cases had a BRCA1 or BRCA2 mutation, as compared with the 26.1% of cases with both early-onset breast cancer and affected relatives. For those reporting malignancy family history other than breast/ovarian cancer, the prevalence of BRCA1/2 mutation is about 20.5%, and it was significantly higher than the patients only with family history of breast/ovarian cancer (P = 0.02). The family history of ovarian cancer (26.7% vs. 11.9%) and stomach cancer (23.8% vs. 11.8%) doubled the incidence of BRCA1/2, but the difference did not reach the statistical significance. Two recurrent mutations in BRCA1, 1100delAT and 5589del8, were identified. The recurrent mutations account for 34.8% BRCA1 mutations in our series. Similar allelotypes were detected in most STR status for those harboring the same mutations. The BRCA1 associated tumors were more likely to exhibit a high tumor grade, negative C-erbB-2/neu status and triple negative (ER, PgR and C-erbB-2/neu negative) status (P < 0.05). We recommended the BRCA1 and BRCA2 genetic analysis could be done for high-risk breast cancer patient in Chinese population, especially for those with both early-onset breast cancer and affected relatives. There may be some degree of shared ancestry for the two recurrent BRCA1 mutations in Chinese.

Characterization of the pathogenic mechanism of a novel BRCA2 variant in a Chinese family

INTRODUCTION

Germline mutations of BRCA1 and BRCA2 account for the majority of hereditary breast cancers, many of which are classified as variants of unknown significance (VUS). We report the identification of a novel BRCA2 variant (c.7806-9T > G) in a Chinese family with multiple breast cancers and document it as a pathogenic mutation.

METHODS

The proband in this family was diagnosed with breast cancer at age 50 with a strong family history of breast cancer. DNA and RNA were extracted from the blood of the proband and her family, and was used for BRCA gene mutation/deletion screening and RNA splicing analysis.

RESULTS

BRCA2 c.7806-9T > G was identified in the proband, which was suggestive of a variant. This change was also found in two sisters of the proband with a history of breast cancer, as well as from the proband's maternal gastric cancer. The only sibling free of breast cancer did not carry the BRCA2 variant, thus demonstrating that the mutation segregates with the clinical phenotype in this family. RNA analysis on the proband blood sample revealed three aberrant splicing variants: c.7806_7874del, c.7806_7976del, and c.7806-8_7806-1ins. The latter causes a frameshift and creates a truncated protein, whilst the other two splicing variants resulted in shorter forms of the protein.

CONCLUSIONS

The identified BRCA2 c.7806-9T > G [Genbank: DQ889340] was found to be pathogenic, based on aberrant splicing events resulting in the formation of truncated protein products. Thus, better understanding and classification of BRCA variants as neutral or disease causing has important implications for genetic counseling so that appropriate management can be given.

Investigating the phenotypes and genotypes of breast cancer in women with African ancestry: the need for more genetic epidemiology

Disparities in incidence, mortality, and age of onset of breast cancer between women of African ancestry and women of other racial/ethnic backgrounds are poorly understood. A more comprehensive elaboration of genetic variants that occur in African women may facilitate a better understanding of the disease in African American women and explain the role of genetic admixture on the variation in the expression of the disease. Large-scale, population-based databases that document the cancer burden of Africa are lacking because of financial and infrastructural limitations. The development of such programs would represent an important cancer control and research strategy.

Predicting BRCA1 and BRCA2 gene mutation carriers: comparison of LAMBDA, BRCAPRO, Myriad II, and modified Couch models

CONTEXT

Models have been developed to predict the probability that a person carries a detectable germline mutation in the BRCA1 or BRCA2 genes. Their relative performance in a clinical setting is unclear.

OBJECTIVE

To compare the performance characteristics of four BRCA1/BRCA2 gene mutation prediction models: LAMBDA, based on a checklist and scores developed from data on Ashkenazi Jewish (AJ) women; BRCAPRO, a Bayesian computer program; modified Couch tables based on regression analyses; and Myriad II tables collated by Myriad Genetics Laboratories.

DESIGN AND SETTING

Family cancer history data were analyzed from 200 probands from the Mayo Clinic Familial Cancer Program, in a multispecialty tertiary care group practice. All probands had clinical testing for BRCA1 and BRCA2 mutations conducted in a single laboratory.

MAIN OUTCOMES MEASURES

For each model, performance was assessed by the area under the receiver operator characteristic curve (ROC) and by tests of accuracy and dispersion. Cases "missed" by one or more models (model predicted less than 10% probability of mutation when a mutation was actually found) were compared across models.

RESULTS

All models gave similar areas under the ROC curve of 0.71 to 0.76. All models except LAMBDA substantially under-predicted the numbers of carriers. All models were too dispersed.

CONCLUSIONS

In terms of ranking, all prediction models performed reasonably well with similar performance characteristics. Model predictions were widely discrepant for some families. Review of cancer family histories by an experienced clinician continues to be vital to ensure that critical elements are not missed and that the most appropriate risk prediction figures are provided.

Racial/ethnic disparities in breast and gynecologic cancer treatment and outcomes

PURPOSE OF REVIEW

To review recent research in racial/ethnic disparities in breast and gynecologic cancers, focusing on disparities occurring postdiagnosis.

RECENT FINDINGS

Mortality statistics show that of the cancers under study, breast cancer has the greatest impact, and of racial/ethnic groups, African Americans suffer the greatest disparities, with highest mortality rates for breast, uterine and cervical cancers, and second highest for ovarian cancer. Recent studies demonstrated that black breast cancer patients suffer more underuse of appropriate adjuvant therapy, and greater delays in diagnosis and institution of treatments, and blacks and Hispanics suffered greater postsurgical pain and symptomatology. Data indicate that the biology of some breast cancers in blacks is unique and more aggressive. One study demonstrated that more black breast cancer patients died of nonbreast cancer causes and that excessive comorbidity in blacks explained substantial amounts of survival disparity. Research is beginning to identify important disparities in nonblack minority racial/ethnic groups, including Hispanics and South Asian Americans.

SUMMARY

Research is continuing to identify and explain an important group of disparities - African American disparities in breast cancer outcomes. Disparities in other minority racial/ethnic groups, and in ovarian, uterine and cervical cancers, are at an emerging stage. Continuing efforts at all fronts are needed.

PancPRO: risk assessment for individuals with a family history of pancreatic cancer

PURPOSE

The rapid fatality of pancreatic cancer is, in large part, the result of an advanced stage of diagnosis for the majority of patients. Identification of individuals at high risk of developing pancreatic cancer is a first step towards the early detection of this disease. Individuals who may harbor a major pancreatic cancer susceptibility gene are one such high-risk group. The goal of this study was to develop and validate PancPRO, a Mendelian model for pancreatic cancer risk prediction in individuals with familial pancreatic cancer, to identify high-risk individuals.

METHODS

PancPRO was built by extending the Bayesian modeling framework developed for BRCAPRO, trained using published data, and validated using independent prospective data on 961 families enrolled onto the National Familial Pancreas Tumor Registry, including 26 individuals who developed incident pancreatic cancer during follow-up.

RESULTS

We developed a risk prediction model, PancPRO, and free software for the estimation of pancreatic cancer susceptibility gene carrier probabilities and absolute pancreatic cancer risk. Model validation demonstrated an observed to predicted pancreatic cancer ratio of 0.83 (95% CI, 0.52 to 1.20) and high discriminatory ability, with an area under the receiver operating characteristic curve of 0.75 (95% CI, 0.68 to 0.81) for PancPRO.

CONCLUSION

PancPRO is the first risk prediction model for pancreatic cancer. When we validated our model using the largest registry of familial pancreatic cancer, our model provided accurate risk assessment. Our findings highlight the importance of detailed family history for clinical cancer risk assessment and demonstrate that accurate genetic risk assessment is possible even when the causative genes are not known.

Sociocultural predictors of breast cancer risk perceptions in African American breast cancer survivors

Although African American breast cancer survivors are at increased risk for developing breast cancer again, empirical data are not available on breast cancer risk perceptions in these women. This study characterized perceived risk of developing breast cancer in African American breast cancer survivors at risk for having a BRCA1 or BRCA1 (BRCA1/2) mutation and identified factors having significant independent associations with risk perceptions. Participants were 95 African American breast cancer survivors at an increased risk for having a BRCA1/2 mutation. Risk perceptions and sociodemographic, clinical, treatment, and sociocultural factors were collected during a structured telephone interview. Most women reported that they had the same or lower risk of developing breast cancer again compared with other women (53%); however, a substantial minority of women (47%) reported that they had a higher or much higher risk. Factors having significant independent associations with heightened risk perceptions included having a >or=10% prior probability of having a BRCA1/2 mutation [odds ratio (OR), 2.91; 95% confidence interval (95% CI), 1.09-7.72; P = 0.03] and more years of formal education (OR, 2.74; 95% CI, 1.02-7.36; P = 0.05). In addition, women who thought about the past a lot were three times more likely to report heightened risk perceptions compared with those who did not think about the past a lot (OR, 3.72; 95% CI, 1.45-9.57; P = 0.01). These results suggest that it may be important to ensure adequate risk comprehension among African American women as part of genetic counseling for inherited breast-ovarian cancer risk. Discussion of risk perceptions within the context of existing beliefs and values may facilitate this process.

Determination of cancer risk associated with germ line BRCA1 missense variants by functional analysis

Germ line inactivating mutations in BRCA1 confer susceptibility for breast and ovarian cancer. However, the relevance of the many missense changes in the gene for which the effect on protein function is unknown remains unclear. Determination of which variants are causally associated with cancer is important for assessment of individual risk. We used a functional assay that measures the transactivation activity of BRCA1 in combination with analysis of protein modeling based on the structure of BRCA1 BRCT domains. In addition, the information generated was interpreted in light of genetic data. We determined the predicted cancer association of 22 BRCA1 variants and verified that the common polymorphism S1613G has no effect on BRCA1 function, even when combined with other rare variants. We estimated the specificity and sensitivity of the assay, and by meta-analysis of 47 variants, we show that variants with <45% of wild-type activity can be classified as deleterious whereas variants with >50% can be classified as neutral. In conclusion, we did functional and structure-based analyses on a large series of BRCA1 missense variants and defined a tentative threshold activity for the classification missense variants. By interpreting the validated functional data in light of additional clinical and structural evidence, we conclude that it is possible to classify all missense variants in the BRCA1 COOH-terminal region. These results bring functional assays for BRCA1 closer to clinical applicability.

Genetic counseling communication with an African American BRCA1 kindred

We studied communication in genetic counseling sessions conducted with an African American, Breast Cancer 1, Early Onset (BRCA1) kindred in the USA. The Roter Interaction Analysis System (RIAS) was used to code and compare two sessions of 46 participants (26 females and 20 males) before and after they underwent genetic testing. Three certified genetic counselors and one medical geneticist conducted the sessions. When compared to pre-test communication, most of the providers' post-test communication was devoted to the provision of biomedical information (including screening recommendations) with fewer questions and psychosocial statements. Clients contributed a similar proportion to the total session dialogue in pre- and post-test sessions (40%). A larger proportion of their post-test session was devoted to indicating receptiveness to provider information than in the pre-test session. We found when providers were informing clients that they were BRCA1 mutation carriers, they provided more biomedical and psychosocial information and asked more psychosocial questions than when talking with non-carriers. This study provides the first description of genetic counseling communication for pre- and post-test BRCA1 sessions with African American individuals.

Differences in breast carcinoma characteristics in newly diagnosed African–American and Caucasian patients

BACKGROUND

Breast carcinomas in African-American patients appear to be more aggressive than in Caucasian patients due to multifactorial differences.

METHODS

The authors compiled pathology data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database regarding stage, histologic grade, and estrogen receptor (ER) expression in breast carcinomas diagnosed in 197,274 African-American and Caucasian patients between 1990 and 2000, and the same information, along with nuclear grade, Ki-67, c-erb-B2, and p53 expression, in 2230 African-American and Caucasian patients diagnosed at Thomas Jefferson University Hospital between 1995 and 2002. Immunohistochemical markers were assayed in paraffin-embedded, formalin-fixed tissue stained with hematoxylin and eosin using antibodies to these proteins, with differences in expression analyzed by the chisquare test.

RESULTS

In both databases, more African-American patients presented with advanced stage tumors and higher histologic (P < .001) and nuclear grade (P < .001) than Caucasian patients. African-American patients had less ER positivity (51.9% vs 63.1%; P < .001) but significantly higher Ki-67 (42.4% vs 28.7%; P < .001) and p53 expression (19.4% vs 13.1%; P < .05) than Caucasian patients with all stages of disease. In addition, the basal or "triple-negative" breast cancer phenotype was more common in African-American patients than in Caucasian patients (20.8% vs 10.4%; P < .0001), and was associated with higher histologic and nuclear grade (P < .0001).

CONCLUSIONS

African-American patients with breast carcinomas are more likely than Caucasian patients to present with tumors that are of a later stage and higher grade, with higher Ki-67 expression and more ER negativity, thereby highlighting a greater need for early screening among African-American women. Molecular studies that may explain these differences, and correlations with survival, have been proposed to identify therapeutic targets.

Combining evidence in hybrid medical decision support models

Hybrid methods are particularly useful for building diagnostic models based on biomedical data due to the wide variety of data types that are routinely encountered. Evaluation of the effectiveness of hybrid systems is complicated when multiple methods are combined to reach a conclusion. In the work described here, methods for combining results based on the general reliability of each model as well as its applicability to the case under evaluation are presented. Reliability measures differ depending on whether symbolic or numeric information is analyzed and depend on the strength of the decision algorithm as well as the soundness of the domain knowledge upon which the decision is based. In addition to reliability, combination of results is complicated by the need to weight each method to form the final conclusion. Weighting factors depend on the degree of certainty that the decision is correct for each of the methods. The process is illustrated in an application to cardiac diagnosis.

Racial disparities in blacks with gynecologic cancers

Black women have a lower incidence of gynecologic cancers but they have a higher mortality associated with their disease. The etiology of the racial disparity in outcome among gynecologic cancer patients is multifactoral and site-specific. Black women with endometrial cancer often present with more advanced stage tumors that are associated with a worse prognosis compared with White women. Evidence suggests that observed disparities in outcome are due to inequalities in treatment or differing biologic etiologies. For cervix cancer, studies have suggested that survival among Black women may be lower than survival among White women that develop this disease. This occurs despite evidence that indicates that Pap smears are utilized similarly by Black and White women for cervix cancer screening. These differences in outcome may become less pronounced when comorbidities are accounted for and inequalities in treatment are eliminated. For ovarian cancer patients, survival has improved with the use of contemporary therapies over the past 30 years in Whites but less so for Blacks. This may be due to differences in the likelihood of primary surgical cytoreductions, which are performed less frequently in some Black women because of extensive metastatic spread or comorbidities. The observed decreases in survival for all 3 gynecologic cancers potentially may be affected by socioeconomic status of the patient in some healthcare settings. An improved understanding of the causative factors associated with racial disparities in gynecologic cancer outcome is necessary to facilitate efforts aimed at correcting this important healthcare problem.

Low rates of acceptance of BRCA1 and BRCA2 test results among African American women at increased risk for hereditary breast-ovarian cancer

PURPOSE

This study evaluated rates of BRCA1 and BRCA2 (BRCA1/2) test result acceptance among African American women and identified determinants of test result acceptance.

METHODS

Acceptance of BRCA1/2 test results was evaluated among 157 African American women at high and moderate risk for having a BRCA1/2 mutation who were offered genetic testing as part of a clinical genetic counseling research program.

RESULTS

Twenty-two percent of women received BRCA1/2 test results. Test result acceptance differed between women with > or =10% prior probability of having a BRCA1/2 mutation (34%) and those who had a 5% prior probability (8%). Among women with > or =10% prior probability, test result acceptors were most likely to be married (OR = 5.29, 95% CI = 1.82, 15.38, P = 0.002) and be less certain about their risk of developing cancer (OR = 3.18, 95% CI = 1.04, 9.80, P = 0.04).

CONCLUSION

These results demonstrate that acceptance of BRCA1/2 test results may be limited among African American women. Being married and having less certainty about one's cancer risk may motivate acceptance of BRCA1/2 test results among African American women. It may be important to emphasize the possibility that BRCA1/2 test results may not clarify cancer risks during pre-test counseling with African American women to ensure informed decision-making about testing.

Prediction of germline mutations and cancer risk in the Lynch syndrome

CONTEXT

Identifying families at high risk for the Lynch syndrome (ie, hereditary nonpolyposis colorectal cancer) is critical for both genetic counseling and cancer prevention. Current clinical guidelines are effective but limited by applicability and cost.

OBJECTIVE

To develop and validate a genetic counseling and risk prediction tool that estimates the probability of carrying a deleterious mutation in mismatch repair genes MLH1, MSH2, or MSH6 and the probability of developing colorectal or endometrial cancer.

DESIGN, SETTING, AND PATIENTS

External validation of the MMRpro model was conducted on 279 individuals from 226 clinic-based families in the United States, Canada, and Australia (referred between 1993-2005) by comparing model predictions with results of highly sensitive germline mutation detection techniques. MMRpro models the autosomal dominant inheritance of mismatch repair mutations, with parameters based on meta-analyses of the penetrance and prevalence of mutations and of the predictive values of tumor characteristics. The model's prediction is tailored to each individual's detailed family history information on colorectal and endometrial cancer and to tumor characteristics including microsatellite instability.

MAIN OUTCOME MEASURE

Ability of MMRpro to correctly predict mutation carrier status, as measured by operating characteristics, calibration, and overall accuracy.

RESULTS

In the independent validation, MMRpro provided a concordance index of 0.83 (95% confidence interval, 0.78-0.88) and a ratio of observed to predicted cases of 0.94 (95% confidence interval, 0.84-1.05). This results in higher accuracy than existing alternatives and current clinical guidelines.

CONCLUSIONS

MMRpro is a broadly applicable, accurate prediction model that can contribute to current screening and genetic counseling practices in a high-risk population. It is more sensitive and more specific than existing clinical guidelines for identifying individuals who may benefit from MMR germline testing. It is applicable to individuals for whom tumor samples are not available and to individuals in whom germline testing finds no mutation.

A review of the ethnic differences in breast cancer

Women of African descent have a lower incidence of breast cancer than their white counterparts; however, the overall age-adjusted breast cancer mortality rates are higher. They also present at a younger age, and have more advanced disease that exhibits poor prognostic features including significantly larger tumors of higher grade, higher rates of estrogen receptor and progesterone receptor negativity and a higher rate of p53 mutations and HRAS1 proto-oncogene expression, all of which confer a poor prognosis. While there are many possible contributory factors to the discrepancies in outcome in women of African descent, there is no satisfactory explanation as to why women of African origin tend to present at a younger age with hormone receptor-negative tumors and more adverse prognostic features.

Prevalence and predictors of BRCA1 and BRCA2 mutations in a population-based study of breast cancer in white and black American women ages 35 to 64 years

Although well studied in families at high-risk, the roles of mutations in the BRCA1 and BRCA2 genes are poorly understood in breast cancers in the general population, particularly in Black women and in age groups outside of the very young. We examined the prevalence and predictors of BRCA1 and BRCA2 mutations in 1,628 women with breast cancer and 674 women without breast cancer who participated in a multicenter population-based case-control study of Black and White women, 35 to 64 years of age. Among cases, 2.4% and 2.3% carried deleterious mutations in BRCA1 and BRCA2, respectively. BRCA1 mutations were significantly more common in White (2.9%) versus Black (1.4%) cases and in Jewish (10.2%) versus non-Jewish (2.0%) cases; BRCA2 mutations were slightly more frequent in Black (2.6%) versus White (2.1%) cases. Numerous familial and demographic factors were significantly associated with BRCA1 and, to a lesser extent, BRCA2 carrier status, when examined individually. In models considering all predictors together, early onset ages in cases and in relatives, family history of ovarian cancer, and Jewish ancestry remained strongly and significantly predictive of BRCA1 carrier status, whereas BRCA2 predictors were fewer and more modest in magnitude. Both the combinations of predictors and effect sizes varied across racial/ethnic and age groups. These results provide first-time prevalence estimates for BRCA1/BRCA2 in breast cancer cases among understudied racial and age groups and show key predictors of mutation carrier status for both White and Black women and women of a wide age spectrum with breast cancer in the general population.

Evaluating nipple discharge

Nipple discharge is the third most common breast complaint after breast pain and breast mass. It is most often a benign process. Up to 50% women in their reproductive years can express one or more drops of fluid from the breast. Nipple discharge can be of several types, including milky, multicolored and sticky, purulent, clear and watery, yellow or serous, pink or serosanguinous, bloody or sanguinous. The characteristics of the nipple discharge help in the early diagnosis and management of breast disease. The most common cause of pathologic nipple discharge is a benign papilloma followed by ductal ectasia, and the least likely is carcinoma. Most nipple discharges are the result of a clinically insignificant benign process; therefore, less invasive, nonsurgical diagnostic modalities have been explored to reduce the need for surgical intervention. The evaluation and diagnosis of nipple discharge is important for the early detection of carcinoma, when present; and, in the case of benign disease, it is necessary to stop the incommodious discharge.

Disparities in Genetic Testing: Thinking Outside the BRCA Box

The impact of predictive genetic testing on cancer care can be measured by the increased demand for and utilization of genetic services as well as in the progress made in reducing cancer risks in known mutation carriers. Nonetheless, differential access to and utilization of genetic counseling and cancer predisposition testing among underserved racial and ethnic minorities compared with the white population has led to growing health care disparities in clinical cancer genetics that are only beginning to be addressed. Furthermore, deficiencies in the utility of genetic testing in underserved populations as a result of limited testing experience and in the effectiveness of risk-reducing interventions compound access and knowledge-base disparities. The recent literature on racial/ethnic health care disparities is briefly reviewed, and is followed by a discussion of the current limitations of risk assessment and genetic testing outside of white populations. The importance of expanded testing in underserved populations is emphasized.

Genetics, epidemiology, and cancer disparities: is it black and white?

Epidemiologic studies attempt to understand the distribution and determinants of human disease. Epidemiologic research often incorporates information about race, ethnicity, or ancestry, usually as a self-identified race or ethnicity (SIRE) variable. Differences in the distribution and determinants of disease on the basis of SIRE may be identified in these studies. In addition, genetic and other biologic differences according to SIRE are frequently reported. If these differences are real and meaningful, they may have value in identifying disease-causative or -preventive factors, and thus may be beneficial to human health. However, the concepts of race, ethnicity, or ancestry are often poorly considered or crudely applied, particularly in genetic studies of disease etiology or outcome. Consequently, results suggesting genetic differences with respect to disease etiology or outcome across SIRE groups may not be meaningful; in fact, these differences may prove harmful if they propagate stereotypes or spurious differences. Therefore, it is critical to properly consider the meaning, definitions, and use of race, ethnicity, or ancestry in molecular epidemiologic studies.

Characterization of BRCA1 and BRCA2 mutations in a large United States sample

PURPOSE

An accurate evaluation of the penetrance of BRCA1 and BRCA2 mutations is essential to the identification and clinical management of families at high risk of breast and ovarian cancer. Existing studies have focused on Ashkenazi Jews (AJ) or on families from outside the United States. In this article, we consider the US population using the largest US-based cohort to date of both AJ and non-AJ families.

METHODS

We collected 676 AJ families and 1,272 families of other ethnicities through the Cancer Genetics Network. Two hundred eighty-two AJ families were population based, whereas the remainder was collected through counseling clinics. We used a retrospective likelihood approach to correct for bias induced by oversampling of participants with a positive family history. Our approach takes full advantage of detailed family history information and the Mendelian transmission of mutated alleles in the family.

RESULTS

In the US population, the estimated cumulative breast cancer risk at age 70 years was 0.46 (95% CI, 0.39 to 0.54) in BRCA1 carriers and 0.43 (95% CI, 0.36 to 0.51) in BRCA2 carriers, whereas ovarian cancer risk was 0.39 (95% CI, 0.30 to 0.50) in BRCA1 carriers and 0.22 (95% CI, 0.14 to 0.32) in BRCA2 carriers. We also reported the prospective risks of developing cancer for cancer-free carriers in 10-year age intervals. We noted a rapid decrease in the relative risk of breast cancer with age and derived its implication for genetic counseling.

CONCLUSION

The penetrance of BRCA mutations in the United States is largely consistent with previous studies on Western populations given the large CIs on existing estimates. However, the absolute cumulative risks are on the lower end of the spectrum.