BRCA1 and BRCA2 pathogenic sequence variants in women of African origin or ancestry

Using Portuguese BRCA pathogenic variation as a model to study the impact of human admixture on human health

BACKGROUND

Admixture occurs between different ethnic human populations. The global colonization in recent centuries by Europeans led to the most significant admixture in human history. While admixture may enhance genetic diversity for better fitness, it may also impact on human health by transmitting genetic variants for disease susceptibility in the admixture population. The admixture by Portuguese global exploration initiated in the 15th century has reached over 20 million of Portuguese-heritage population worldwide. It provides a valuable model to study the impact of admixture on human health. BRCA1 and BRCA2 (BRCA) are two of the important tumor suppressor genes. The pathogenic variation (PV) in BRCA is well determined to cause high risk of hereditary breast and ovarian cancer. Tracing the distribution of Portuguese BRCA PV in Portuguese-heritage population will help to understand the impact of admixture on cancer susceptibility in modern humans. In this study, we analyzed the distribution of the Portuguese-originated BRCA variation in Brazilian population, which has high degree Portuguese-heritage.

METHODS

By comprehensive data mining, standardization and annotation, we generated a Portuguese-derived BRCA variation dataset and a Brazilian-derived BRCA variation dataset. We compared the two BRCA variation datasets to identify the BRCA variants shared between the two populations.

RESULTS

The Portuguese-derived BRCA variation dataset consists of 220 BRCA variants including 78 PVs from 11,482 Portuguese cancer patients, 93 (42.2%) in BRCA1 and 127 (57.7%) in BRCA2. Of the 556 Portuguese BRCA PV carriers carrying the 78 PVs, 331 (59.5%) carried the three Portuguese-BRCA founder PVs of BRCA1 c.2037delinsCC, BRCA1 c.3331_3334del and BRCA2 c.156_157insAlu. The Brazilian-derived BRCA variation dataset consists of 255 BRCA PVs from 7,711 cancer patients, 136 (53.3%) in BRCA1 and 119 (46.6%) in BRCA2. We developed an open database named dbBRCA-Portuguese ( https://genemutation.fhs.um.edu.mo/dbbrca-portuguese/ ) and an open database named dbBRCA-Brazilian ( https://genemutation.fhs.um.edu.mo/dbbrca-brazilian ) to host the BRCA variation data from Portuguese and Brazilian populations. We compared the BRCA PV datasets between Portuguese and Brazilian populations, and identified 29 Portuguese-specific BRCA PVs shared between Portuguese and Brazilian populations, 14 in BRCA1 including the Portuguese founder BRCA1 c.3331_3334del and BRCA1 c.2037delinsCC, and 15 in BRCA2 including the Portuguese founder BRCA2 c.156_157insAlu. Searching the 78 Portuguese BRCA PVs in over 5,000 ancient human genomes identified evolution origin for only 8 PVs in Europeans dated between 37,470 and 3,818 years before present, confirming the Portuguese-specificity of Portuguese BRCA PVs; comparing the 78 Portuguese BRCA PVs Portuguese, 255 Brazilian BRCA PVs, and 134 African BRCA PVs showed little overlapping, ruling out the possibility that the BRCA PVs shared between Portuguese and Brazilian may also be contributed by African.

CONCLUSION

Our study provides evidence that the admixture in recent human history contributed to cancer susceptibility in modern humans.

Barriers and facilitators to genetic testing for breast and ovarian cancer amongst Black African women in Luton (UK)

Evidence suggests that although Black African women have the lowest incidence of breast and ovarian cancer, they have the highest mortality rate and low rates of uptake for cancer screening services for these conditions in the United Kingdom (UK). This study aimed to explore the perceived barriers and facilitators to genetic testing for breast and ovarian cancer amongst Black African women in Luton (UK). We conducted a qualitative study that included one face-to-face and five telephone focus group discussions. Consistent with the health belief model, a focus group discussion guide was developed. A total of 24 participants, aged 23-57 who self-identified as Black African women and who were English speakers residing in Luton, took part in the focus group discussions. Purposive and snowballing sampling were used to recruit the participants for this study. The focus group discussions were recorded, transcribed per verbatim, coded and analyzed using an inductive thematic analysis approach, and the findings were classified. Nine themes emerged from the narratives obtained including six barriers and three facilitators. Barriers to genetic testing included (1) Cost and affordability, (2) Lack of knowledge, awareness, and family health history knowledge, (3) Language barrier, immigration, and distrust in western healthcare services, (4) Fear, (5) Cultural, religious, and intergenerational views and perceptions, and (6) Eligibility for genetic testing for the BRCA1/2 pathogenic variants and a lack of referral to specialist genetic clinics. Facilitators to genetic testing included (7) Availability of tests cost-free under the National Health Service (NHS) (8) Family members' health and (9) Awareness and education on genetic testing. The barriers and facilitators identified could enable policy makers and healthcare services alike to gain a better understanding of the factors influencing Black African women's decision-making process toward genetic testing. Ultimately, this work can inform interventions aiming to increase the uptake of genetic testing among this group.

Disparities in care of older adults of color with cancer: A narrative review

This review describes the barriers and challenges faced by older adults of color with cancer and highlights methods to improve their overall care. In the next decade, cancer incidence rates are expected to increase in the United States for people aged ≥65 years. A large proportion will be older adults of color who often have worse outcomes than older White patients. Many issues contribute to racial disparities in older adults, including biological factors and social determinants of health (SDOH) related to healthcare access, socioeconomic concerns, systemic racism, mistrust, and the neighborhood where a person lives. These disparities are exacerbated by age-related challenges often experienced by older adults, such as decreased functional status, impaired cognition, high rates of comorbidities and polypharmacy, poor nutrition, and limited social support. Additionally, underrepresentation of both patients of color and older adults in cancer clinical research results in a lack of adequate data to guide the management of these patients. Use of geriatric assessments (GA) can aid providers in uncovering age-related concerns and personalizing interventions for older patients. Research demonstrates the ability of GA-directed care to result in fewer treatment-related toxicities and improved quality of life, thus supporting the routine incorporation of validated GA into these patients' care. GA can be enhanced by including evaluation of SDOH, which can help healthcare providers understand and address the needs of older adults of color with cancer who face disparities related to their age and race.

Heterogeneous genetic architectures and evolutionary genomics of prostate cancer in Sub-Saharan Africa

Men of African descent have the highest prostate cancer (CaP) incidence and mortality rates, yet the genetic basis of CaP in African men has been understudied. We used genomic data from 3,963 CaP cases and 3,509 controls recruited in Ghana, Nigeria, Senegal, South Africa, and Uganda, to infer ancestry-specific genetic architectures and fine-mapped disease associations. Fifteen independent associations at 8q24.21, 6q22.1, and 11q13.3 reached genome-wide significance, including four novel associations. Intriguingly, multiple lead SNPs are private alleles, a pattern arising from recent mutations and the out-of-Africa bottleneck. These African-specific alleles contribute to haplotypes with odds ratios above 2.4. We found that the genetic architecture of CaP differs across Africa, with effect size differences contributing more to this heterogeneity than allele frequency differences. Population genetic analyses reveal that African CaP associations are largely governed by neutral evolution. Collectively, our findings emphasize the utility of conducting genetic studies that use diverse populations.

Breast Cancer Germline Genetic Counseling and Testing for Populations of African Heritage Globally: A Scoping Review on Research, Practice, and Bioethical Considerations

PURPOSE

Despite the disproportionately high risk of breast cancer among women of African heritage, little is known about the facilitators and barriers to implementing germline genetic testing and counseling (GT/C).

METHODS

This scoping review followed guidelines recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. Published manuscripts from database inception through 2021 were sourced from PubMed, Cumulative Index to Nursing and Allied Health Literature via EBSCO, Embase, Cochrane Library, and Scopus. Search terms were used to retrieve articles addressing (1) African heritage, (2) breast cancer, and (3) GT or GC. The screening involved abstract and title review and full-text review. Data were extracted for all articles meeting the inclusion criteria.

RESULTS

A total of 154 studies were included. Most studies that took place were conducted in the United States (71.4%), and most first authors (76.9%) were from the United States. GT was conducted in 73 (49.7%) studies. BRCA1/BRCA2 were the most commonly studied genes for germline mutations. GC was conducted in 49 studies (33.3%), and perspectives on GC were evaluated in 43 (29.3%). The use of racial/ethnic categories varied broadly, although African American was most common (40.1%). Racism was mentioned in three studies (2.0%).

CONCLUSION

There is a growing body of literature on GT/C for breast cancer in women of African heritage. Future studies on GT/C of African populations should consider increased clarity around racial/ethnic categorizations, continued community engagement, and intentional processes for informed consent.

Germline Testing Around the Globe: Challenges in Different Practice Settings

Cancer is an increasing global public health burden. Lately, more emphasis has emerged on the importance of heredity in cancer, mostly driven by the introduction of germline genetic variants-directed therapeutics. It is true that 40% of cancer risk is attributed to modifiable environmental and lifestyle factors; still, 16% of cancers could be heritable, accounting for 2.9 of the 18.1 million cases diagnosed worldwide. At least two third of those will be diagnosed in countries with limited resources-low- and middle-income countries, especially where high rates of consanguine marriage and early age at diagnosis are already prevalent. Both are hallmarks of hereditary cancer. This creates a new opportunity for prevention, early detection, and recently therapeutic intervention. However, this opportunity is challenged by many obstacles along the path to addressing germline testing in patients with cancer in the clinic worldwide. Global collaboration and expertise exchange are important to bridge the knowledge gap and facilitate practical implementation. Adapting existing guidelines and prioritization according to local resources are essential to address the unique needs and overcome the unique barriers of each society.

Ethnic-specificity, evolution origin and deleteriousness of Asian BRCA variation revealed by over 7500 BRCA variants derived from Asian population

Pathogenic variation in BRCA1 and BRCA2 (BRCA) causes high risk of breast and ovarian cancer, and BRCA variation data are important markers for BRCA-related clinical cancer applications. However, comprehensive BRCA variation data are lacking from the Asian population despite its large population size, heterogenous genetic background and diversified living environment across the Asia continent. We performed a systematic study on BRCA variation in Asian population including extensive data mining, standardization, annotation and characterization. We identified 7587 BRCA variants from 685 592 Asian individuals in 40 Asia countries and regions, including 1762 clinically actionable pathogenic variants and 4915 functionally unknown variants (https://genemutation.fhs.um.edu.mo/Asian-BRCA/). We observed the highly ethnic-specific nature of Asian BRCA variants between Asian and non-Asian populations and within Asian populations, highlighting that the current European descendant population-based BRCA data is inadequate to reflect BRCA variation in the Asian population. We also provided archeological evidence for the evolutionary origin and arising time of Asian BRCA variation. We further provided structural-based evidence for the deleterious variants enriched within the functionally unknown Asian BRCA variants. The data from our study provide a current view of BRCA variation in the Asian population and a rich resource to guide clinical applications of BRCA-related cancer for the Asian population.

Disparities in Breast Cancer Outcomes and How to Resolve Them

There has been a 40% decline in breast cancer age-adjusted death rate since 1990. Black American women have not experienced as great a decline; indeed, the Black-White disparity in mortality in the United States is greater today than it has ever been. Certain states (areas of residence), however, do not see such dramatic differences in outcome by race. This latter finding suggests much more can be done to reduce disparities and prevent deaths. Interventions to get high-quality care (screening, diagnostics, and treatment) involve understanding the needs and concerns of the patient and addressing those needs and concerns. Patient navigators are 1 way to improve outcomes.

A Review of the Nucleic Acid-Based Lateral Flow Assay for Detection of Breast Cancer from Circulating Biomarkers at a Point-of-Care in Low Income Countries

The current levels of breast cancer in African women have contributed to the high mortality rates among them. In South Africa, the incidence of breast cancer is also on the rise due to changes in behavioural and biological risk factors. Such low survival rates can be attributed to the late diagnosis of the disease due to a lack of access and the high costs of the current diagnostic tools. Breast cancer is asymptomatic at early stages, which is the best time to detect it and intervene to prevent high mortality rates. Proper risk assessment, campaigns, and access to adequate healthcare need to be prioritised among patients at an early stage. Early detection of breast cancer can significantly improve the survival rate of breast cancer patients, since therapeutic strategies are more effective at this stage. Early detection of breast cancer can be achieved by developing devices that are simple, sensitive, low-cost, and employed at point-of-care (POC), especially in low-income countries (LICs). Nucleic-acid-based lateral flow assays (NABLFAs) that combine molecular detection with the immunochemical visualisation principles, have recently emerged as tools for disease diagnosis, even for low biomarker concentrations. Detection of circulating genetic biomarkers in non-invasively collected biological fluids with NABLFAs presents an appealing and suitable method for POC testing in resource-limited regions and/or LICs. Diagnosis of breast cancer at an early stage will improve the survival rates of the patients. This review covers the analysis of the current state of NABLFA technologies used in developing countries to reduce the scourge of breast cancer.

APOEε4 Genotype Is Related to Brain Amyloid Among Mexican Americans in the HABS-HD Study

Introduction

Despite the fact that Hispanics are expected to experience the greatest increase in Alzheimer's disease (AD) and related dementias (ADRDs) by 2060, very little data is available regarding the fundamental biomarkers of AD among Mexican Americans who reflect the majority of Hispanics in the U.S. Here we sought to examine the link between APOEε4 genotype and brain amyloid among Mexican Americans as compared to non-Hispanic white participants from the Health & Aging Brain Study - Health Disparities (HABS-HD) cohort.

Methods

PET amyloid (florbetaben) data were analyzed from 105 Mexican American and 150 non-Hispanic white participants.

Results

Among Mexican Americans, APOEε4 genotype presence was associated with Global SUVR (p = 0.003) as well as amyloid burden in the frontal (p < 0.001), lateral parietal (p = 0.003), lateral temporal (p = 0.008) and anterior-posterior cingulate (p = 0.005) regions of interest (ROIs). Among non-Hispanic white participants, APOEε4 genotype presence was associated with Global SUVR (p < 0.001) as well as amyloid burden in the frontal (p < 0.001), lateral parietal (p < 0.001), lateral temporal (p < 0.001) and anterior-posterior cingulate (p < 0.001) regions of interest (ROIs). The association between APOEε4 genotype and cerebral amyloid was strongest among non-Hispanic white participants.

Discussion/Conclusion

Despite the fact that the APOEε4 genotype is significantly less frequent among Mexican Americans, its presence remains to be a significant risk factor among this group for AD pathological burden across all regions. Additional work is needed to understand the presence, progression, and clinical impact of brain amyloid among Mexican Americans.

Analysis of the genomic landscapes of Barbadian and Nigerian women with triple negative breast cancer

PURPOSE

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype that disproportionately affects women of African ancestry (WAA) and is often associated with poor survival. Although there is a high prevalence of TNBC across West Africa and in women of the African diaspora, there has been no comprehensive genomics study to investigate the mutational profile of ancestrally related women across the Caribbean and West Africa.

METHODS

This multisite cross-sectional study used 31 formalin-fixed paraffin-embedded (FFPE) samples from Barbadian and Nigerian TNBC participants. High-resolution whole exome sequencing (WES) was performed on the Barbadian and Nigerian TNBC samples to identify their mutational profiles and comparisons were made to African American, European American and Asian American sequencing data obtained from The Cancer Genome Atlas (TCGA). Whole exome sequencing was conducted on tumors with an average of 382 × coverage and 4335 × coverage for pooled germline non-tumor samples.

RESULTS

Variants detected at high frequency in our WAA cohorts were found in the following genes NBPF12, PLIN4, TP53 and BRCA1. In the TCGA TNBC cases, these genes had a lower mutation rate, except for TP53 (32% in our cohort; 63% in TCGA-African American; 67% in TCGA-European American; 63% in TCGA-Asian). For all altered genes, there were no differences in frequency of mutations between WAA TNBC groups including the TCGA-African American cohort. For copy number variants, high frequency alterations were observed in PIK3CA, TP53, FGFR2 and HIF1AN genes.

CONCLUSION

This study provides novel insights into the underlying genomic alterations in WAA TNBC samples and shines light on the importance of inclusion of under-represented populations in cancer genomics and biomarker studies.

Mutational spectrum of breast cancer susceptibility genes among women ascertained in a cancer risk clinic in Northeast Brazil

PURPOSE

There is a paucity of data on the spectrum and prevalence of pathogenic variants among women of African ancestry in the Northeast region of Brazil.

METHODS

We performed BROCA panel sequencing to identify inherited loss-of-function variants in breast cancer susceptibility genes among 292 Brazilian women referred to a single institution cancer risk assessment program.

RESULTS

The study included a convenient cohort of 173 women with invasive breast cancer (cases) and 119 women who were cancer-free at the time of ascertainment. The majority of the women self-reported as African-descended (67% for cases and 90.8% for unaffected volunteers). Thirty-seven pathogenic variants were found in 36 (20.8%) patients. While the spectrum of pathogenic variants was heterogeneous, the majority (70.3%) of the pathogenic variants were detected in high-risk genes BRCA1, BRCA2, PALB2, and TP53. Pathogenic variants were also found in the ATM, BARD1, BRIP1, FAM175A, FANCM, NBN, and SLX4 genes in 6.4% of the affected women. Four recurrent pathogenic variants were detected in 11 patients of African ancestry. Only one unaffected woman had a pathogenic variant in the RAD51C gene. Different risk assessment models examined performed well in predicting risk of carrying germline loss-of-function variants in BRCA1 and/or BRCA2 in breast cancer cases.

CONCLUSION

The high prevalence and heterogenous spectrum of pathogenic variants identified among self-reported African descendants in Northeast Brazil is consistent with studies in other African ancestry populations with a high burden of aggressive young onset breast cancer. It underscores the need to integrate comprehensive cancer risk assessment and genomic testing in the management of newly diagnosed Black women with breast cancer across the African Diaspora, enabling improved cancer control in admixed underserved and understudied populations.

Cancer in sub-Saharan Africa: a Lancet Oncology Commission

In sub-Saharan Africa (SSA), urgent action is needed to curb a growing crisis in cancer incidence and mortality. Without rapid interventions, data estimates show a major increase in cancer mortality from 520 348 in 2020 to about 1 million deaths per year by 2030. Here, we detail the state of cancer in SSA, recommend key actions on the basis of analysis, and highlight case studies and successful models that can be emulated, adapted, or improved across the region to reduce the growing cancer crises. Recommended actions begin with the need to develop or update national cancer control plans in each country. Plans must include childhood cancer plans, managing comorbidities such as HIV and malnutrition, a reliable and predictable supply of medication, and the provision of psychosocial, supportive, and palliative care. Plans should also engage traditional, complementary, and alternative medical practices employed by more than 80% of SSA populations and pathways to reduce missed diagnoses and late referrals. More substantial investment is needed in developing cancer registries and cancer diagnostics for core cancer tests. We show that investments in, and increased adoption of, some approaches used during the COVID-19 pandemic, such as hypofractionated radiotherapy and telehealth, can substantially increase access to cancer care in Africa, accelerate cancer prevention and control efforts, increase survival, and save billions of US dollars over the next decade. The involvement of African First Ladies in cancer prevention efforts represents one practical approach that should be amplified across SSA. Moreover, investments in workforce training are crucial to prevent millions of avoidable deaths by 2030. We present a framework that can be used to strategically plan cancer research enhancement in SSA, with investments in research that can produce a return on investment and help drive policy and effective collaborations. Expansion of universal health coverage to incorporate cancer into essential benefits packages is also vital. Implementation of the recommended actions in this Commission will be crucial for reducing the growing cancer crises in SSA and achieving political commitments to the UN Sustainable Development Goals to reduce premature mortality from non-communicable diseases by a third by 2030.

Neurodegeneration from the AT(N) framework is different among Mexican Americans compared to non-Hispanic Whites: A Health & Aging Brain among Latino Elders (HABLE) Study

INTRODUCTION

We sought to examine a magnetic resonance imaging (MRI)-based marker of neurodegeneration from the AT(N) (amyloid/tau/neurodegeneration) framework among a multi-ethnic, community-dwelling cohort.

METHODS

Community-dwelling Mexican Americans and non-Hispanic White adults and elders were recruited. All participants underwent comprehensive assessments including an interview, functional exam, clinical labs, informant interview, neuropsychological testing and 3T MRI of the brain. A neurodegeneration MRI meta-region of interest (ROI) biomarker for the AT(N) framework was calculated.

RESULTS

Data were examined from n = 1305 participants. Mexican Americans experienced N at significantly younger ages. The N biomarker was significantly associated with cognitive outcomes. N was significantly impacted by cardiovascular factors (e.g., total cholesterol, low-density lipoprotein) among non-Hispanic Whites whereas diabetes (glucose, HbA1c, duration of diabetes) and sociocultural (household income, acculturation) factors were strongly associated with N among Mexican Americans.

DISCUSSION

The prevalence, progression, timing, and sequence of the AT(N) biomarkers must be examined across diverse populations.

New Insights Into c.815_824dup Pathogenic Variant of BRCA1 in Inherited Breast Cancer: A Founder Mutation of West African Origin

Founder mutations have been reported in BRCA1 and BCRA2 in different ethnic groups with inherited breast cancer. Testing of targeted mutations in specific populations is important for cancer prevention in mutation carriers. In Sub-Saharan Africa, only a few studies have reported specific founder mutations in inherited breast cancer. The pathogenic variant c.815_824dup of BRCA1 has been reported as the most frequent among African American populations with inherited breast cancer and was supposed to have a West African origin. Recent report from Senegal identified this variant in women with inherited breast cancer at the highest frequency ever reported. The variant was linked to a common haplotype confirming its founder effect in West Africa. In this article, we review the mutation history of c.815_824dup and discuss how it spread out of Africa through the transatlantic slave trade.

Understanding how genetic ancestry may influence cancer development

Of the multifactorial determinants that lead to cancer health disparities among race groups, quantified genetic ancestry has begun to expand our knowledge beyond self-reported race. However, it is essential to study these biological determinants in the context of social determinants to truly improve clinical tools and achieve equitable survival outcomes.

Knowledge and perceptions of BRCA1/2 genetic testing and needs of diverse women with a personal or family history of breast cancer in South Florida

The vast majority of (BRCA1/2) genetic testing has been conducted in White women, in particular Ashkenazi Jewish women, with limited information available for Black and Hispanic women. Understanding perspectives of those who are underserved is critical to developing interventions to support inclusive approaches to genetic testing. This qualitative study explored knowledge and perceptions of BRCA1/2 genetic testing among diverse women in South Florida. We also explored participants' information needs. Convenience sampling was used to recruit a diverse group of 15 women with a personal or family history of breast cancer. We conducted semi-structured interviews and used grounded theory method to analyze the data. Five themes were identified: (1) lacking awareness and knowledge of BRCA1/2 genetic testing and results among Black women, (2) perceiving BRCA1/2 genetic testing as beneficial to themselves and a way to be proactive about cancer risk, (3) perceiving BRCA1/2 genetic testing as beneficial to family members, (4) interactions with healthcare providers and the healthcare system that shape genetic testing experiences, and (5) information needs for reducing cancer risk and promoting health. Our findings suggest that diverse underserved women perceived genetic testing as beneficial to themselves and family members. Women needed more information about the BRCA genes and genetic testing, prevention strategies, and the latest breast cancer research. Healthcare providers, particularly nurse practitioners, need to engage diverse high-risk women in discussions about their cancer risk, address unmet information needs, and, in particular, educate Black women about the benefits of pursuing genetic testing.

BRCA1 and BRCA2 Variation in Taiwanese General Population and the Cancer Cohort

BRCA1 and BRCA2 (BRCA) play essential roles in maintaining genome stability. Rapidly evolving human BRCA generates oncogenic variants causing high cancer risk. BRCA variation is ethnic-specific in reflecting adaptation and/or effects of genetic drift. Taiwanese population of 23.8 million is an admixture of multiple ethnic origins; Taiwan's subtropical and tropical climate and geographically islandic location provide a unique natural environment. Therefore, Taiwanese population provides a unique model to study human BRCA variation. Through collecting, standardizing, annotating, and classifying publicly available BRCA variants derived from Taiwanese general population and the cancer cohort, we identified 335 BRCA variants, of which 164 were from 1,517 non-cancer individuals, 126 from 2,665 cancer individuals, and 45 from both types of individuals. We compared the variant data with those from other ethnic populations such as mainland Chinese, Macau Chinese, Japanese, Korean, Indian, and non-Asians. We observed that the sharing rates with other Asian ethnic populations were correlated with its genetic relationship. Over 60% of the 335 Taiwanese BRCA variants were VUS, unclassified variants, or novel variants, reflecting the ethnic-specific features of Taiwanese BRCA variation. While it remains challenging to classify these variants, our structural and in silico analyses predicted their enrichment of BRCA deleterious variants. We further determined the 3.8% prevalence of BRCA pathogenic variants in the Taiwanese breast cancer cohort, and determined 0.53% prevalence of the BRCA pathogenic variants in Taiwanese general population, with the estimated 126,140 BRCA pathogenic variant carriers. We identified BRCA2 c.5164_5165delAG at BRCA2 BRC6 motif as a potential founder mutation in Taiwanese population. Our study on BRCA variation in Taiwanese and other East Asian populations demonstrates that ethnic specificity is a common phenomenon for BRCA variation in East Asian population; the data generated from the study provide a reference for clinical applications in BRCA-related cancer in Taiwanese population.

Undercutting efforts of precision medicine: roadblocks to minority representation in breast cancer clinical trials

Precision (or personalized) medicine holds great promise in the treatment of breast cancer. The success of personalized medicine is contingent upon inclusivity and representation for minority groups in clinical trials. In this article, we focus on the roadblocks for the African American demographic, including the barriers to access and enrollment in breast oncology trials, the prevailing classification of race and ethnicity, and the need to refine monolithic categorization by employing genetic ancestry mapping tools for a more accurate determination of race or ethnicity.

Ethnic-specific BRCA1/2 variation within Asia population: evidence from over 78 000 cancer and 40 000 non-cancer cases of Indian, Chinese, Korean and Japanese populations

BACKGROUND

Germline mutation in BRCA1 and BRCA2 (BRCA) is genetic predisposition for breast and ovarian cancer. Identification of mutation carriers is a critical step to prevent and treat the cancer in the mutation carriers. Human BRCA variation has been well determined as ethnic-specific by studies in Ashkenazi Jewish, Polish and Icelandic populations in the 1990s. However, sufficient evidence is lacking to determine if ethnic-specific BRCA variation is also present in Asia population, which is the largest and the most diversified in modern humans. Our current study aims to investigate ethnic-specific BRCA variation in Asian population.

METHODS

We performed a comprehensive data mining to collect BRCA variation data in Indian, Chinese, Korean and Japanese populations derived from over 78 000 cancer and 40 000 non-cancer cases. We standardised all BRCA variation data following the international standard. We made a systematic comparison between the datasets including variant composition, variation spectrum, variant type, clinical class, founder mutation and high-frequent variants.

RESULTS

Our analysis showed that over half of the Asian BRCA variants were Asian-specific, and significant differences were present between the four Asia populations in each category analysed.

CONCLUSION

Data from our study reveal that ethnic-specific BRCA variation is commonly present in Asia population as existing in non-Asian populations. Our study indicates that ethnicity should be an important factor to consider in prevention and treatment of BRCA mutation-related cancer in the Asia population. We recommend that the current BRCA variation databases should include ethnic variation information in order to function as true global BRCA references.

High expression of MKK3 is associated with worse clinical outcomes in African American breast cancer patients

BACKGROUND

African American women experience a twofold higher incidence of triple-negative breast cancer (TNBC) and are 40% more likely to die from breast cancer than women of other ethnicities. However, the molecular bases for the survival disparity in breast cancer remain unclear, and no race-specific therapeutic targets have been proposed. To address this knowledge gap, we performed a systematic analysis of the relationship between gene mRNA expression and clinical outcomes determined for The Cancer Genome Atlas (TCGA) breast cancer patient cohort.

METHODS

The systematic differential analysis of mRNA expression integrated with the analysis of clinical outcomes was performed for 1055 samples from the breast invasive carcinoma TCGA PanCancer cohorts. A deep learning fully-convolutional model was used to determine the association between gene expression and tumor features based on breast cancer patient histopathological images.

RESULTS

We found that more than 30% of all protein-coding genes are differentially expressed in White and African American breast cancer patients. We have determined a set of 32 genes whose overexpression in African American patients strongly correlates with decreased survival of African American but not White breast cancer patients. Among those genes, the overexpression of mitogen-activated protein kinase kinase 3 (MKK3) has one of the most dramatic and race-specific negative impacts on the survival of African American patients, specifically with triple-negative breast cancer. We found that MKK3 can promote the TNBC tumorigenesis in African American patients in part by activating of the epithelial-to-mesenchymal transition induced by master regulator MYC.

CONCLUSIONS

The poor clinical outcomes in African American women with breast cancer can be associated with the abnormal elevation of individual gene expression. Such genes, including those identified and prioritized in this study, could represent new targets for therapeutic intervention. A strong correlation between MKK3 overexpression, activation of its binding partner and major oncogene MYC, and worsened clinical outcomes suggests the MKK3-MYC protein-protein interaction as a new promising target to reduce racial disparity in breast cancer survival.

Immune Responses and Risk of Triple-negative Breast Cancer: Implications for Higher Rates among African American Women

The etiology of triple-negative breast cancers (TNBC) is poorly understood. As many TNBCs develop prior to the initiation of breast cancer screening or at younger ages when the sensitivity of mammography is comparatively low, understanding the etiology of TNBCs is critical for discovering novel prevention approaches for these tumors. Furthermore, the higher incidence rate of estrogen receptor-negative breast cancers, and specifically, of TNBCs, among young African American women (AAW) versus white women is a source of racial disparities in breast cancer mortality. Whereas immune responses to TNBCs have received considerable attention in relation to prognosis and treatment, the concept that dysregulated immune responses may predispose to the development of TNBCs has received limited attention. We present evidence that dysregulated immune responses are critical in the pathogenesis of TNBCs, based on the molecular biology of the cancers and the mechanisms proposed to mediate TNBC risk factors. Furthermore, proposed risk factors for TNBC, especially childbearing without breastfeeding, high parity, and obesity, are more prevalent among AAW than white women. Limited data suggest genetic differences in immune responses by race, which favor a stronger Thr type 2 (Th2) immune response among AAW than white women. Th2 responses contribute to wound-healing processes, which are implicated in the pathogenesis of TNBCs. Accordingly, we review data on the link between immune responses and TNBC risk and consider whether the prevalence of risk factors that result in dysregulated immunity is higher among AAW than white women.