Using genome and transcriptome data from African-ancestry female participants to identify putative breast cancer susceptibility genes.

African-ancestry (AA) participants are underrepresented in genetics research. Here, we conducted a transcriptome-wide association study (TWAS) in AA female participants to identify putative breast cancer susceptibility genes. We built genetic models to predict levels of gene expression, exon junction, and 3' UTR alternative polyadenylation using genomic and transcriptomic data generated in normal breast tissues from 150 AA participants and then used these models to perform association analyses using genomic data from 18,034 cases and 22,104 controls. At Bonferroni-corrected P < 0.05, we identified six genes associated with breast cancer risk, including four genes not previously reported (CTD-3080P12.3, EN1, LINC01956 and NUP210L). Most of these genes showed a stronger association with risk of estrogen-receptor (ER) negative or triple-negative than ER-positive breast cancer. We also replicated the associations with 29 genes reported in previous TWAS at P < 0.05 (one-sided), providing further support for an association of these genes with breast cancer risk. Our study sheds new light on the genetic basis of breast cancer and highlights the value of conducting research in AA populations.

Genome-wide association analyses of breast cancer in women of African ancestry identify new susceptibility loci and improve risk prediction.

We performed genome-wide association studies of breast cancer including 18,034 cases and 22,104 controls of African ancestry. Genetic variants at 12 loci were associated with breast cancer risk (P < 5 × 10-8), including associations of a low-frequency missense variant rs61751053 in ARHGEF38 with overall breast cancer (odds ratio (OR) = 1.48) and a common variant rs76664032 at chromosome 2q14.2 with triple-negative breast cancer (TNBC) (OR = 1.30). Approximately 15.4% of cases with TNBC carried six risk alleles in three genome-wide association study-identified TNBC risk variants, with an OR of 4.21 (95% confidence interval = 2.66-7.03) compared with those carrying fewer than two risk alleles. A polygenic risk score (PRS) showed an area under the receiver operating characteristic curve of 0.60 for the prediction of breast cancer risk, which outperformed PRS derived using data from females of European ancestry. Our study markedly increases the population diversity in genetic studies for breast cancer and demonstrates the utility of PRS for risk prediction in females of African ancestry.

The risk of skin cancer in women who carry BRCA1 or BRCA2 mutations.

BACKGROUND: It has not been clearly established if skin cancer or melanoma are manifestations of BRCA1 or BRCA2 mutation carrier status. Estimating the risk of skin cancer is an important step towards developing screening recommendations. METHODS: We report the findings of a prospective cohort study of 6,207 women from North America who carry BRCA1 or BRCA2 mutations. Women were followed from the date of baseline questionnaire to the diagnosis of skin cancer, to age 80 years, death from any cause, or the date of last follow-up. RESULTS: During the mean follow-up period of eight years, 3.7% of women with a BRCA1 mutation (133 of 3,623) and 3.8% of women with a BRCA2 mutation (99 of 2,584) reported a diagnosis of skin cancer (including both keratinocyte carcinomas and melanoma). The cumulative risk of all types of skin cancer from age 20 to 80 years was 14.1% for BRCA1 carriers and 10.7% for BRCA2 carriers. The cumulative risk of melanoma was 2.5% for BRCA1 carriers and 2.3% for BRCA2 carriers, compared to 1.5% for women in the general population in the United States. The strongest risk factor for skin cancer was a prior diagnosis of skin cancer. CONCLUSION: The risk of non-melanoma skin cancer in women who carry a mutation in BRCA1 or BRCA2 is similar to that of non-carrier women. The risk of melanoma appears to be slightly elevated. We suggest that a referral to a dermatologist or primary care provider for BRCA mutation carriers for annual skin examination and counselling regarding limiting UV exposure, the use of sunscreen and recognizing the early signs of melanoma might be warranted, but further studies are necessary.

Bilateral Oophorectomy and All-Cause Mortality in Women With BRCA1 and BRCA2 Sequence Variations.

Importance: Preventive bilateral salpingo-oophorectomy is offered to women at high risk of ovarian cancer who carry a pathogenic variant in BRCA1 or BRCA2; however, the association of oophorectomy with all-cause mortality has not been clearly defined. Objective: To evaluate the association between bilateral oophorectomy and all-cause mortality among women with a BRCA1 or BRCA2 sequence variation. Design, Setting, and Participants: In this international, longitudinal cohort study of women with BRCA sequence variations, information on bilateral oophorectomy was obtained via biennial questionnaire. Participants were women with a BRCA1 or BRCA2 sequence variation, no prior history of cancer, and at least 1 follow-up questionnaire completed. Women were followed up from age 35 to 75 years for incident cancers and deaths. Cox proportional hazards regression was used to estimate the hazard ratios (HRs) and 95% CIs for all-cause mortality associated with a bilateral oophorectomy (time dependent). Data analysis was performed from January 1 to June 1, 2023. Exposures: Self-reported bilateral oophorectomy (with or without salpingectomy). Main Outcomes and Measures: All-cause mortality, breast cancer-specific mortality, and ovarian cancer-specific mortality. Results: There were 4332 women (mean age, 42.6 years) enrolled in the cohort, of whom 2932 (67.8%) chose to undergo a preventive oophorectomy at a mean (range) age of 45.4 (23.0-77.0) years. After a mean follow-up of 9.0 years, 851 women had developed cancer and 228 had died; 57 died of ovarian or fallopian tube cancer, 58 died of breast cancer, 16 died of peritoneal cancer, and 97 died of other causes. The age-adjusted HR for all-cause mortality associated with oophorectomy was 0.32 (95% CI, 0.24-0.42; P < .001). The age-adjusted HR was 0.28 (95% CI, 0.20-0.38; P < .001) and 0.43 (95% CI, 0.22-0.90; P = .03) for women with BRCA1 and BRCA2 sequence variations, respectively. For women with BRCA1 sequence variations, the estimated cumulative all-cause mortality to age 75 years for women who had an oophorectomy at age 35 years was 25%, compared to 62% for women who did not have an oophorectomy. For women with BRCA2 sequence variations, the estimated cumulative all-cause mortality to age 75 years was 14% for women who had an oophorectomy at age 35 years compared to 28% for women who did not have an oophorectomy. Conclusions and Relevance: In this cohort study among women with a BRCA1 or BRCA2 sequence variation, oophorectomy was associated with a significant reduction in all-cause mortality.

MRI Surveillance and Breast Cancer Mortality in Women With BRCA1 and BRCA2 Sequence Variations.

Importance: Magnetic resonance imaging (MRI) surveillance is offered to women with a pathogenic variant in the BRCA1 or BRCA2 gene who face a high lifetime risk of breast cancer. Surveillance with MRI is effective in downstaging breast cancers, but the association of MRI surveillance with mortality risk has not been well defined. Objective: To compare breast cancer mortality rates in women with a BRCA1 or BRCA2 sequence variation who entered an MRI surveillance program with those who did not. Design, Setting, and Participants: Women with a BRCA1 or BRCA2 sequence variation were identified from 59 participating centers in 11 countries. Participants completed a baseline questionnaire between 1995 and 2015 and a follow-up questionnaire every 2 years to document screening histories, incident cancers, and vital status. Women who had breast cancer, a screening MRI examination, or bilateral mastectomy prior to enrollment were excluded. Participants were followed up from age 30 years (or the date of the baseline questionnaire, whichever was later) until age 75 years, the last follow-up, or death from breast cancer. Data were analyzed from January 1 to July 31, 2023. Exposures: Entrance into an MRI surveillance program. Main Outcomes and Measures: Cox proportional hazards modeling was used to estimate the hazard ratios (HRs) and 95% CIs for breast cancer mortality associated with MRI surveillance compared with no MRI surveillance using a time-dependent analysis. Results: A total of 2488 women (mean [range] age at study entry 41.2 [30-69] years), with a sequence variation in the BRCA1 (n = 2004) or BRCA2 (n = 484) genes were included in the analysis. Of these participants, 1756 (70.6%) had at least 1 screening MRI examination and 732 women (29.4%) did not. After a mean follow-up of 9.2 years, 344 women (13.8%) developed breast cancer and 35 women (1.4%) died of breast cancer. The age-adjusted HRs for breast cancer mortality associated with entering an MRI surveillance program were 0.20 (95% CI, 0.10-0.43; P < .001) for women with BRCA1 sequence variations and 0.87 (95% CI, 0.10-17.25; P = .93) for women with BRCA2 sequence variations. Conclusion and Relevance: Results of this cohort study suggest that among women with a BRCA1 sequence variation, MRI surveillance was associated with a significant reduction in breast cancer mortality compared with no MRI surveillance. Further studies of women with BRCA2 sequence variations are needed to ascertain these women obtain the same benefits associated with MRI surveillance.

Risk-reducing mastectomy and breast cancer mortality in women with a BRCA1 or BRCA2 pathogenic variant: an international analysis.

BACKGROUND: Risk-reducing mastectomy (RRM) is offered to women with a BRCA1 or BRCA2 pathogenic variant, however, there are limited data on the impact on breast cancer mortality. METHODS: Participants were identified from a registry of women with BRCA1/2 pathogenic variants. We used a pseudo-randomised trial design and matched one woman with a RRM to one woman without a RRM on year of birth, gene, and country. We estimated the hazard ratio (HR) and 95% confidence intervals (CI) for dying of breast cancer in the follow-up period. RESULTS: There were 1654 women included; 827 assigned to the RRM arm and 827 assigned to the control arm. After a mean follow-up of 6.3 years, there were 20 incident breast cancers (including 15 occult cancers) and two breast cancer deaths in the RRM arm, and 100 incident breast cancers and 7 breast cancer deaths in the control arm (HR = 0.26; 95% CI 0.05-1.35; p = 0.11). The probability of dying of breast cancer within 15 years after RRM was 0.95%. CONCLUSIONS: In women with a BRCA1 or BRCA2 pathogenic variant, RRM reduces the risk of breast cancer, and the probability of dying of breast cancer is low.

NCCN Guidelines® Insights: Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 2.2024.

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic focus primarily on assessment of pathogenic/likely pathogenic (P/LP) variants associated with increased risk of breast, ovarian, pancreatic, and prostate cancer, including BRCA1, BRCA2, CDH1, PALB2, PTEN, and TP53, and recommended approaches to genetic counseling/testing and care strategies in individuals with these P/LP variants. These NCCN Guidelines Insights summarize important updates regarding: (1) a new section for transgender, nonbinary and gender diverse people who have a hereditary predisposition to cancer focused on risk reduction strategies for ovarian cancer, uterine cancer, prostate cancer, and breast cancer; and (2) testing criteria and management associated with TP53 P/LP variants and Li-Fraumeni syndrome.

Piloting a Spanish-Language Web-Based Tool for Hereditary Cancer Genetic Testing.

The delivery of hereditary cancer pre-test education among Spanish-language patients is impeded by the dearth of Spanish-speaking genetic counselors. To address this gap, we evaluated a web-based genetic education tool delivered in Spanish to provide information typically discussed during an initial genetic counseling session. Spanish-speaking patients with a personal or family history of cancer were recruited at two centers in Puerto Rico and through social media. A total of 41 participants completed a survey before and after viewing the tool to measure knowledge, attitudes, and decisional empowerment. A subset of 10 participants completed a virtual semi-structured interview to assess the usability and appropriateness of the tool. Paired t-tests were calculated to evaluate changes in knowledge and attitudes. A McNemar test assessed for decisional empowerment. Interview transcripts were translated from Spanish to English and inductively coded and analyzed. Results revealed significant increases in knowledge (p < 0.001), while attitudes about genetic testing did not change (p = 0.77). The proportion of individuals who felt fully informed and empowered to decide about whether to undergo genetic testing increased from 15% to 51% (p < 0.001). Qualitative data indicated that participants found the tool easy to use with informative and valuable content. Our findings suggest this Spanish-language tool is a user-friendly and scalable solution to help inform and empower many individuals to decide about cancer genetic testing, recognizing that others may still benefit from genetic counseling prior to testing.

Theory-based behavior change intervention to increase uptake of risk-reducing salpingo-oophorectomy in women with a BRCA1 or BRCA2 pathogenic variant: The PREVENT randomized controlled trial.

OBJECTIVE: To evaluate the effect of a theory-based behavioral intervention delivered by genetic counselors on the uptake of risk-reducing salpingo-oophorectomy (RRSO) at 12 and 24 months by women with a BRCA1 or BRCA2 pathogenic variant (PV) compared to women who received usual care. METHODS: In this two-arm, multi-site randomized controlled trial participants were randomized to receive a theoretically-guided behavioral telephone intervention or usual care. Outcome data were collected at 12 and 24 months. Participants in the usual care arm were offered the intervention after 12 months. RESULTS: Data on 107 participants were included in the analysis. There was no significant difference in the proportion of women who had a RRSO by 1 year (28.6%- intervention; 22.9%- usual care (p = 0.54)). At 1 year, women who received the intervention had significantly lower mean decisional conflict (pinteraction <0.001) and a higher mean knowledge score at one-year compared to usual care (pinteraction <0.001). At 2 years, 53.9% of participants in the intervention arm had RRSO compared to 32.6% in usual care (p = 0.05). CONCLUSIONS: A theory-based behavioral intervention delivered by genetic counselors to women with a BRCA PV who chose not to have the recommended RRSO was effective at reducing decisional conflict and increasing knowledge in women with a BRCA1 or BRCA2 PV.

Tamoxifen and the risk of breast cancer in women with a BRCA1 or BRCA2 mutation.

PURPOSE: Chemoprevention with a selective estrogen receptor modulator (tamoxifen or raloxifene) is a non-surgical option offered to high-risk women to reduce the risk of breast cancer. The evidence for tamoxifen benefit is based on trials conducted among predominantly postmenopausal women from the general population and on studies of contralateral breast cancer in women with a pathogenic variant (mutation hereafter) in BRCA1 or BRCA2. Tamoxifen has not been assessed as a primary prevention agent in women with an inherited BRCA mutation. METHODS: We conducted a prospective analysis of tamoxifen chemoprevention and the risk of breast cancer in women with a BRCA1 or BRCA2 mutation. Data on tamoxifen (and raloxifene) use was collected by questionnaire and updated biennially. Information on incident cancers was collected by self-report and was confirmed by medical record review. In a matched analysis, we estimated the hazard ratio (HR) and 95% confidence intervals (CI) for developing a first primary breast cancer associated with tamoxifen or raloxifene use, using Cox proportional hazards analysis. RESULTS: There were 4578 unaffected women in the cohort, of whom 137 reported tamoxifen use (3%), 83 reported raloxifene use (2%) and 12 used both drugs (0.3%). Women who used tamoxifen or raloxifene were matched 1:3 with women who used neither drug on year of birth, country of residence, year of study entry and gene (BRCA1 or BRCA2). We generated 202 matched pairs. After a mean follow-up of 6.8 years, there were 22 incident breast cancers diagnosed among tamoxifen/raloxifene users (10.9% of users) and 71 cases diagnosed among non-users (14.3% of non-users; HR = 0.64; 95% CI 0.40-1.03; P = 0.07). CONCLUSION: Chemoprevention may be an effective risk-reduction option for BRCA mutation carriers, but further studies with longer follow-up are necessary.

Factors that differentiate cancer risk management decisions among females with pathogenic/likely pathogenic variants in PALB2, CHEK2, and ATM.

PURPOSE: Following disclosure of pathogenic or likely pathogenic variants in hereditary cancer genes, patients face cancer risk management decisions. Through this mixed-methods study, we investigated cancer risk management decisions among females with pathogenic or likely pathogenic variants in PALB2, CHEK2, and ATM to understand why some patients follow National Comprehensive Cancer Network guidelines, whereas others do not. METHODS: Survey and interview data were cross-analyzed using a 3-stage approach. Identified factors were used to conduct coincidence analysis and differentiate between combinations of factors that result in following or not following guidelines. RESULTS: Of the 13 participants who underwent guideline inconsistent prophylactic surgery, 12 fit 1 of 3 unique patterns: (1) cancer-related anxiety in the absence of trust in care, (2) provider recommending surgery inconsistent with National Comprehensive Cancer Network guidelines, or (3) surgery occurring before genetic testing. Two unique patterns were found among 18 of 20 participants who followed guidelines: (1) anxiety along with trust in care or (2) lack of anxiety and no prophylactic surgery before testing. CONCLUSION: Health care provider recommendations and trust in care may influence whether individuals receive care that is congruent with risk levels conferred by specific genes. Interventions are needed to improve provider knowledge, patient trust in non-surgical care, and patient anxiety.

Management of individuals with germline pathogenic/likely pathogenic variants in CHEK2: A clinical practice resource of the American College of Medical Genetics and Genomics (ACMG).

PURPOSE: Although the role of CHEK2 germline pathogenic variants in cancer predisposition is well known, resources for managing CHEK2 heterozygotes in clinical practice are limited. METHODS: An international workgroup developed guidance on clinical management of CHEK2 heterozygotes informed by peer-reviewed publications from PubMed. RESULTS: Although CHEK2 is considered a moderate penetrance gene, cancer risks may be considered as a continuous variable, which are influenced by family history and other modifiers. Consequently, early cancer detection and prevention for CHEK2 heterozygotes should be guided by personalized risk estimates. Such estimates may result in both downgrading lifetime breast cancer risks to those similar to the general population or upgrading lifetime risk to a level at which CHEK2 heterozygotes are offered high-risk breast surveillance according to country-specific guidelines. Risk-reducing mastectomy should be guided by personalized risk estimates and shared decision making. Colorectal and prostate cancer surveillance should be considered based on assessment of family history. For CHEK2 heterozygotes who develop cancer, no specific targeted medical treatment is recommended at this time. CONCLUSION: Systematic prospective data collection is needed to establish the spectrum of CHEK2-associated cancer risks and to determine yet-unanswered questions, such as the outcomes of surveillance, response to cancer treatment, and survival after cancer diagnosis.

Applying the framework for developing and evaluating complex interventions to increase family communication about hereditary cancer.

Objective: Evaluate an intervention to increase family communication (FC) of positive hereditary cancer test results using the Framework for Developing and Evaluating Complex Interventions (FDECI). Methods: We developed 'programme theory' during the FDECI development phase by aligning intervention components with behavior change techniques (BCTs) and theoretical factors expected to improve FC. During the feasibility phase, we obtained feedback from 12 stakeholder interviews. Results: Intervention components aligned with a total of 14 unique BCTs for which prior evidence links the BCT to theoretical factors that influence behavior change. Constructive stakeholder feedback included: more information desired, rewording to support autonomy by highlighting options, and improvements to navigation, visuals, and audio. Positive comments included: comprehensiveness of materials, modeling of conversations, and usefulness of the materials for helping a person prepare to share positive test results. Conclusion: The first FDECI phases were helpful for improving the intervention and planning our ongoing effectiveness and future implementation phases. Innovation: Our application of the FDECI is novel, including plans to test our 'programme theory' using coincidence analysis (CNA) to determine who accesses which intervention materials, how utilizing certain materials impact the aligned theoretical factors, and whether these in turn make a difference in the behavioral outcome.

Inherited Cancer Knowledge Among Black Females with Breast Cancer Before and After Viewing a Web-Based Educational Video.

Purpose: Scalable solutions are needed to make pre-test genetic education about inherited cancer risk accessible across diverse and underserved populations. We evaluated an automated strategy to deliver genetic education through a web-based video among young Black females with breast cancer. Methods: 96 participants were recruited through state cancer registries in Florida and Tennesee. All participants viewed a 12 min video and completed a ten question quiz on inherited cancer knowledge before and after viewing the video. Median pre- and postvideo knowledge scores were categorized as <60% versus ≥60% and compared across demographic and clinical characteristics using binary logistic regression. Results: Of the 96 participants, mean age was 51, over 50% had income <$50 K, over 40% did not graduate college or have private insurance, and over 70% had previous genetic testing. Median knowledge scores significantly increased after viewing the video (p < 001), with no significant differences in those with or without prior testing. A higher post-video knowledge score was associated with an income ≥$50 K, a college degree, and private insurance (all p < .05). Conclusion: Among a population of young Black breast cancer patients, the educational video significantly increased knowledge. Findings support the use of automated pre-test educational tools as a scalable solution to make these services more accessible across populations.

The risks of cancer in older women with BRCA pathogenic variants: How far have we come?

BACKGROUND: The purpose of this study was to estimate the cumulative risks of all cancers in women from 50 to 75 years of age with a BRCA1 or BRCA2 pathogenic variant. METHODS: Participants were women with BRCA1 or BRCA2 pathogenic variants from 85 centers in 16 countries. Women were eligible if they had no cancer before the age of 50 years. Participants completed a baseline questionnaire and follow-up questionnaires every 2 years. Women were followed from age 50 until a diagnosis of cancer, death, age 75, or last follow-up. The risk of all cancers combined from age 50 to 75 was estimated using the Kaplan-Meier method. RESULTS: There were 2211 women included (1470 BRCA1 and 742 BRCA2). There were 379 cancers diagnosed in the cohort between 50 and 75 years. The actuarial risk of any cancer from age 50 to 75 was 49% for BRCA1 and 43% for BRCA2. Breast (n = 186) and ovarian (n = 45) were the most frequent cancers observed. For women who had both risk-reducing mastectomy and bilateral salpingo-oophorectomy before age 50, the risk of developing any cancer between age 50 and 75 was 9%. CONCLUSION: Women with a BRCA1 or BRCA2 pathogenic variant have a high risk of cancer between the ages of 50 and 75 years and should be counselled appropriately.

Receipt of Bilateral Mastectomy Among Women With Hereditary Breast Cancer.

This case series study examines differences in surgical treatment among adult females with invasive breast cancer who have pathogenic or likely pathogenic variants in genes with high vs moderate breast cancer penetrance.

Evaluating Costs Associated With Genetic Counseling Among Commercially Insured US Patients With Cancer From 2013 to 2019.

This cohort study describes the prevalence of out-of-pocket costs for cancer-related genetic counseling services in the US.

Racial/Ethnic Disparities in Mortality Related to Access to Care for Major Cancers in the United States.

Importance: The reasons underlying racial/ethnic mortality disparities for cancer patients remain poorly understood, especially regarding the role of access to care. Participants: Over five million patients with a primary diagnosis of lung, breast, prostate, colon/rectum, pancreas, ovary, or liver cancer during 2004-2014, were identified from the National Cancer Database. Cox proportional hazards models were applied to estimate hazard ratios (HR) and 95% confidence intervals (CI) for total mortality associated with race/ethnicity, and access to care related factors (i.e., socioeconomic status [SES], insurance, treating facility, and residential type) for each cancer. Results: Racial/ethnic disparities in total mortality were observed across seven cancers. Compared with non-Hispanic (NH)-white patients, NH-black patients with breast (HR = 1.27, 95% CI: 1.26 to 1.29), ovarian (HR = 1.20, 95% CI: 1.17 to 1.23), prostate (HR = 1.31, 95% CI: 1.30 to 1.33), colorectal (HR = 1.11, 95% CI: 1.10 to 1.12) or pancreatic (HR = 1.03, 95% CI: 1.02 to 1.05) cancers had significantly elevated mortality, while Asians (13-31%) and Hispanics (13-19%) had lower mortality for all cancers. Racial/ethnic disparities were observed across all strata of access to care related factors and modified by those factors. NH-black and NH-white disparities were most evident among patients with high SES or those with private insurance, while Hispanic/Asian versus NH-white disparities were more evident among patients with low SES or those with no/poor insurance. Conclusions and Relevance: Racial/ethnic mortality disparities for major cancers exist across all patient groups with different access to care levels. The influence of SES or insurance on mortality disparity follows different patterns for racial/ethnic minorities versus NH-whites. Impact: Our study highlights the need for racial/ethnic-specific strategies to reduce the mortality disparities for major cancers.

Evaluating breast cancer predisposition genes in women of African ancestry.

PURPOSE: Studies conducted primarily among European ancestry women reported 12 breast cancer predisposition genes. However, etiologic roles of these genes in breast cancer among African ancestry women have been less well-investigated. METHODS: We conducted a case-control study in African American women, which included 1117 breast cancer cases and 2169 cancer-free controls, and a pooled analysis, which included 7096 cases and 8040 controls of African descent. Odds ratios of associations with breast cancer risk were estimated. RESULTS: Using sequence data, we identified 61 pathogenic variants in 12 breast cancer predisposition genes, including 11 pathogenic variants not yet reported in previous studies. Pooled analysis showed statistically significant associations of breast cancer risk with pathogenic variants in BRCA1, BRCA2, PALB2, ATM, CHEK2, TP53, NF1, RAD51C, and RAD51D (all P < .05). The associations with BRCA1, PALB2, and RAD51D were stronger for estrogen receptor (ER)-negative than for ER-positive breast cancer (P heterogeneity < .05), whereas the association with CHEK2 was stronger for ER-positive than for ER-negative breast cancer. CONCLUSION: Our study confirmed previously identified associations of breast cancer risk with BRCA1, BRCA2, PALB2, ATM, TP53, NF1, and CHEK2 and provided new evidence to extend the associations of breast cancer risk with RAD51C and RAD51D, which was identified previously in European ancestry populations, to African ancestry women.