Racial differences in the expression of cell cycle-regulatory proteins in breast carcinoma

Simulating the population impact of interventions to reduce racial gaps in breast cancer treatment

BACKGROUND

Inequities in guideline-concordant treatment receipt contribute to worse survival in Black patients with breast cancer. Inequity-reduction interventions (eg, navigation, bias training, tracking dashboards) can close such treatment gaps. We simulated the population-level impact of statewide implementation of inequity-reduction interventions on racial breast cancer inequities in North Carolina.

METHODS

Using registry-linked multipayer claims data, we calculated inequities between Black and White patients receiving endocrine therapy (n = 12 033) and chemotherapy (n = 1819). We then built cohort-stratified (endocrine therapy and chemotherapy) and race-stratified Markov models to simulate the potential increase in the proportion of patients receiving endocrine therapy or chemotherapy and subsequent improvements in breast cancer outcomes if inequity-reducing intervention were implemented statewide. We report uncertainty bounds representing 95% of simulation results.

RESULTS

In total, 75.6% and 72.1% of Black patients received endocrine therapy and chemotherapy, respectively, over the 2006-2015 and 2004-2015 periods (vs 79.3% and 78.9% of White patients, respectively). Inequity-reduction interventions could increase endocrine therapy and chemotherapy receipt among Black patients to 89.9% (85.3%, 94.6%) and 85.7% (80.7%, 90.9%). Such interventions could also decrease 5-year and 10-year breast cancer mortality gaps from 3.4 to 3.2 (3.0, 3.3) and from 6.7 to 6.1 (5.9, 6.4) percentage points in the endocrine therapy cohorts and from 8.6 to 8.1 (7.7, 8.4) and from 8.2 to 7.8 (7.3, 8.1) percentage points in the chemotherapy cohorts.

CONCLUSIONS

Inequity-focused interventions could improve cancer outcomes for Black patients, but they would not fully close the racial breast cancer mortality gap. Addressing other inequities along the cancer continuum (eg, screening, pre- and postdiagnosis risk factors) is required to achieve full equity in breast cancer outcomes.

Analysis of gene expression profiles to elucidate racial differences in African American and White patients with Triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the second most diagnosed subtype of breast cancer. It is known to be the most aggressive one that lacks known targetable receptors. One of the concerns in TNBC is the disparities in its prevalence and tumor pathogenesis among women with non-Hispanic African American backgrounds. Despite extensive research, the genetic underpinnings that lead to these disparities remain elusive. The current study aims to provide initiative for further clinical research in the development of targeted therapy for TNBC. Gene expression profiles from African American (AA) and European American (EA) patients with TNBC were collected from Gene Expression Omnibus and performed differential gene expression (DEG)analysis. Candidate genes for a significant correlation between expression and survival rates for breast invasive carcinoma were analyzed using UALCAN. The DAVID annotation tool, Enrichr web server, KEGG database, and Gene Ontology (GO) database were used for functional enrichment analysis of target genes. The Network Analyst server was used to identify ligands with strong affinities, SeamDock server for molecular docking between the biomarkers/associated ligands and examined protein-protein interactions (PPI) from the STRING server. Data from public breast cancer cohorts was utilized to identify expression patterns associated with poor survival outcomes of AA patients with TNBC. Our results showed three genes of interest ( CCT3 , LSM2 , and MRPS16 ) and potential ligands for molecular docking. Molecular docking was performed for the ICG001 ligand to CCT3 (binding affinities of -9.3 kcal/mol and -8.9 kcal/mol) and other interacting proteins ( CDC20 and PPP2CA ) with high degrees of connectivity. The results determined molecular docking of ICG001 to the CDC20 protein resulted in the highest binding affinity. Our results demonstrated that CCT3 and its interacting partners could serve as potential biomarkers due to their association with the survival outcome of AA patients with TNBC and ICG 001 could be the therapeutic lead for these biomarkers.

A Public Health Emergency: Breast Cancer Among Black Communities in the United States

While Black people have a similar incidence of breast cancer compared to White people, they have a 40% increased death rate. Black people are more likely to be diagnosed with aggressive subtypes such as triple-negative breast cancer. However, despite biological factors, systemic racism and social determinants of health create delays in care and barriers to treatment. While genetic testing holds incredible promise for Black people, uptake remains low and results may be challenging to interpret. There is a need for more robust, multidisciplinary, and antiracist interventions to reverse breast cancer-related racial disparities.

TCGA Expression Analyses of 10 Carcinoma Types Reveal Clinically Significant Racial Differences

Epidemiological studies reveal disparities in cancer incidence and outcome rates between racial groups in the United States. In our study, we investigated molecular differences between racial groups in 10 carcinoma types. We used publicly available data from The Cancer Genome Atlas to identify patterns of differential gene expression in tumor samples obtained from 4112 White, Black/African American, and Asian patients. We identified race-dependent expression of numerous genes whose mRNA transcript levels were significantly correlated with patients' survival. Only a small subset of these genes was differentially expressed in multiple carcinomas, including genes involved in cell cycle progression such as CCNB1, CCNE1, CCNE2, and FOXM1. In contrast, most other genes, such as transcriptional factor ETS1 and apoptotic gene BAK1, were differentially expressed and clinically significant only in specific cancer types. Our analyses also revealed race-dependent, cancer-specific regulation of biological pathways. Importantly, homology-directed repair and ERBB4-mediated nuclear signaling were both upregulated in Black samples compared to White samples in four carcinoma types. This large-scale pan-cancer study refines our understanding of the cancer health disparity and can help inform the use of novel biomarkers in clinical settings and the future development of precision therapies.

Clinical Outcomes and Immune Markers by Race in a Phase I/II Clinical Trial of Durvalumab Concomitant with Neoadjuvant Chemotherapy in Early-Stage TNBC

PURPOSE

The incidence of triple-negative breast cancer (TNBC) is higher among Black or African American (AA) women, yet they are underrepresented in clinical trials. To evaluate safety and efficacy of durvalumab concurrent with neoadjuvant chemotherapy for stage I-III TNBC by race, we enrolled additional AA patients to a Phase I/II clinical trial.

PATIENTS AND METHODS

Our study population included 67 patients. The primary efficacy endpoint was pathologic complete response (pCR; ypT0/is, N0) rate. χ2 tests were used to evaluate associations between race and baseline characteristics. Cox proportional hazards models were used to assess association between race and overall survival (OS) and event-free survival (EFS). Multivariate logistic regression analyses were used to evaluate associations between race and pCR, immune-related adverse events (irAE) and recurrence.

RESULTS

Twenty-one patients (31%) self-identified as AA. No significant associations between race and baseline tumor stage (P = 0.40), PD-L1 status (0.92), and stromal tumor-infiltrating lymphocyte (sTIL) count (P = 0.57) were observed. pCR rates were similar between AA (43%) and non-AA patients (48%; P = 0.71). Three-year EFS rates were 78.3% and 71.4% in non-AA and AA patients, respectively [HR, 1.451; 95% confidence interval (CI), 0.524-4.017; P = 0.474]; 3-year OS was 87% and 81%, respectively (HR, 1.72; 95% CI, 0.481-6.136; P = 0.405). The incidence of irAEs was similar between AA and non-AA patients and no significant associations were found between irAEs and pathologic response.

CONCLUSIONS

pCR rates, 3-year OS and EFS after neoadjuvant immunotherapy and chemotherapy were similar in AA and non-AA patients. Toxicities, including the frequency of irAEs, were also similar.

Pattern of survival of breast cancer patients in a tertiary hospital in South West Nigeria

Background of the study

Breast cancer is the most common cancer among women in both developed and developing nations. The survival of breast cancer is increasing in developed countries with improved treatment modalities, while still very poor in developing countries. In Nigeria, few breast cancer survival data are available.

Research design

This is a retrospective cross-sectional study.

Objectives

To determine the survival of breast cancer patients and possible factors influencing it.

Methodology

Socio-demographic and clinical variables from treatment records and case notes of breast cancer patients treated from 1 January 2004 to 31 December 2008 at the Department of Radiation Oncology, University College Hospital, Ibadan. The status of patients was determined at 2 and 5 years after diagnosis. The survival of patients with breast cancer was compared using Log Rank test according to socio-demographic and clinical variables. The median survival times were obtained from the Kaplan–Meier survival curve. Cox’s proportional hazard model was fitted for those that were statistically significant in the Log Rank test. Missing data were reported as unknown, not documented or missing.

Results

A total of 378 patients were analysed. Age ranged between 22.0 and 87.0 years with mean of 47.6 (standard deviation (SD) = 11.2) years. Almost all patients were females (98.4%). More than half (55.3%) presented at stage III, 28.0% had metastasis and the stage was unknown in about 6.6% of the patients. Invasive ductal carcinoma was the most prevalent histology (89.2%). Only 124 (32.8%) patients had their histological grade stated and most of the patients had no immunohistochemistry done. All the patients had radiotherapy, chemotherapy and surgery. About 25.1% of the patients were lost to follow up. The 2- and 5-year survival rates were 56.4% and 37.6%, respectively. The 2- and 5-year survival rates according to stage were stage I (80.0% and 66.7%), stage II (67.7% and 57.6%), stage III (51.4% and 27.9%) and stage IV (37.9% and 13.8%). Median survival time was 41 months (95%CI = 35.0–44.0). The disease-free survival at 2 and 5 years was 66.6% and 60.3%, respectively. Median time for recurrence was 8.0 months. Level of education, height, tumour unilaterality, clinical tumour size, stage at presentation, presence of distant metastases, clinical axillary lymph node metastasis, supraclavicular node metastasis, mode of surgery and axillary clearance were found to have statistically significant association with survival.

Conclusion

A large number of the patients in our study presented at a young age, late with advanced stage disease which results in poor survival outcome.

Breast Cancer Mortality Hot Spots Among Black Women With de Novo Metastatic Breast Cancer

Background

Black women living in southern states have the highest breast cancer mortality rate in the United States. The prognosis of de novo metastatic breast cancer is poor. Given these mortality rates, we are the first to link nationally representative data on breast cancer mortality hot spots (counties with high breast cancer mortality rates) with cancer mortality data in the United States and investigate the association of geographic breast cancer mortality hot spots with de novo metastatic breast cancer mortality among Black women.

Methods

We identified 7292 Black women diagnosed with de novo metastatic breast cancer in Surveillance, Epidemiology, and End Results (SEER). The county-level characteristics were obtained from 2014 County Health Rankings and linked to SEER. We used Cox proportional hazards models to calculate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for mortality between hot spot and non-hot spot counties.

Results

Among 7292 patients, 393 (5.4%) resided in breast cancer mortality hot spots. Women residing in hot spots had similar risks of breast cancer-specific mortality (aHR = 0.99, 95% CI = 0.85 to 1.15) and all-cause mortality (aHR = 0.97, 95% CI = 0.84 to 1.11) as women in non-hot spots after adjusting for individual and tumor-level factors and treatments. Additional adjustment for county-level characteristics did not impact mortality.

Conclusion

Living in a breast cancer mortality hot spot was not associated with de novo metastatic breast cancer mortality among Black women. Future research should begin to examine variation in both individual and population-level determinants, as well as in molecular and genetic determinants that underlie the aggressive nature of de novo metastatic breast cancer.

Vitamin D Receptor Polymorphisms and Cancer

Increasing scientific evidence supports the link between vitamin D and cancer risk. The active metabolite 1,25(OH)2D exerts its activity by binding to the vitamin D receptor (VDR), an intracellular receptor that mediates transcriptional activation and repression of target genes. The binding of 1,25(OH)2D to VDR is able to regulate hundreds of different genes. VDR is active in virtually all tissues including the colon, breast, lung, ovary, bone, kidney, parathyroid gland, pancreatic b-cells, monocytes, T lymphocytes, melanocytes, keratinocytes, and also cancer cells.The relevance of VDR gene restriction fragment length polymorphisms for various types of cancer has been investigated by a great number of studies.We have carried out a systematic review of the literature to analyze the relevance of more VDR polymorphisms (Fok1, Bsm1, Taq1, Apa1, and Cdx2) for individual malignancies considering ethnicity as a key factor for heterogeneity.Up to December 2018, we identified 176 independent studies with data to assess the risk of breast, prostate, colorectal, skin (melanoma and non-melanoma skin cancer), lung, ovarian, kidney, bladder, gallbladder, esophageal, thyroid, head and neck, liver and pancreatic cancer, oral squamous cell carcinoma, non-Hodgkin lymphoma, multiple myeloma and sarcoma.Significant associations with VDR polymorphisms have been reported for prostate (Fok1, Bsm1, Taq1, Apa1, Cdx2), breast (Fok1, Bsm1, Taq1, Apa1, CdX2), colorectal (Fok1, Bsm1, Taq1, Apa1), and skin cancer (Fok1, Bsm1, Taq1). Very few studies reported risk estimates for the other cancer sites.Conflicting data have been reported for most malignancies, and at present, it is still not possible to make any definitive statements about the importance of the VDR genotype for cancer risk. It seems probable that other factors such as ethnicity, phenotype, 25(OH)D plasma levels, and UV radiation exposure play a role as confounding factors and introduce heterogeneity.To conclude, there is some indication that VDR polymorphisms may modulate the risk of some cancer sites and in future studies VDR genetic variation should be integrated also with assessment of vitamin D status and stratified by ethnicity.

Molecular and Cellular Factors Associated with Racial Disparity in Breast Cancer

Recent studies have demonstrated that racial differences can influence breast cancer incidence and survival rate. African American (AA) women are at two to three fold higher risk for breast cancer than other ethnic groups. AA women with aggressive breast cancers show worse prognoses and higher mortality rates relative to Caucasian (CA) women. Over the last few years, effective treatment strategies have reduced mortality from breast cancer. Unfortunately, the breast cancer mortality rate among AA women remains higher compared to their CA counterparts. The focus of this review is to underscore the racial differences and differential regulation/expression of genetic signatures in CA and AA women with breast cancer. Moreover, immune cell infiltration significantly affects the clinical outcome of breast cancer. Here, we have reviewed recent findings on immune cell recruitment in the tumor microenvironment (TME) and documented its association with breast cancer racial disparity. In addition, we have extensively discussed the role of cytokines, chemokines, and other cell signaling molecules among AA and CA breast cancer patients. Furthermore, we have also reviewed the distinct genetic and epigenetic changes in AA and CA patients. Overall, this review article encompasses various molecular and cellular factors associated with breast cancer disparity that affects mortality and clinical outcome.

Understanding breast cancer disparities-a multi-scale challenge

Despite convergence of overall breast cancer incidence rates between European American (EA) and African American (AA) women, disparities in mortality persist. The factors contributing to differences in mortality rates across population groups remain controversial and range from population genetics to sociodemographic influences. This review explores the complex multi-factorial nature of tumor-intrinsic and -extrinsic factors that impact the biology and clinical outcomes of breast cancer patients. In addition to summarizing the current state of breast cancer disparities research, we also motivate the development of integrative multi-scale approaches involving interdisciplinary teams to tackle this complex clinical challenge.

The impact of sociodemographic factors and health insurance coverage in the diagnosis and clinicopathological characteristics of breast cancer in Brazil: AMAZONA III study (GBECAM 0115)

PURPOSE

In Brazil, the available cancer registries are deficient in number and quality and, hence, little information is known regarding sociodemographic, clinicopathological characteristics, treatment patterns, and outcomes of breast cancer (BC) patients. We performed the AMAZONA III/ GBECAM 0115 study and in this analysis, we describe patients' characteristics at diagnosis and their association with health insurance type.

METHODS

This is a prospective cohort study developed in 23 sites in Brazil including women with newly diagnosed invasive BC from January 2016 to March 2018. In order to compare healthcare insurance type, we considered patients who were treated under the Brazilian public health system as publicly insured, and women who had private insurance or paid for their treatment as privately insured.

RESULTS

A total of 2950 patients were included in the study. Median age at diagnosis was 53.9 years; 63.1% were publicly insured. The majority of patients (68.6%) had stage II-III breast cancer and ductal carcinoma histology (80.9%). The most common breast cancer subtype was luminal A-like (48.0%) followed by luminal B-HER2 positive-like (17.0%) and triple-negative (15.6%). Luminal A was more frequent in private (53.7% vs. 44.2%, p < .0001) than public, whereas Luminal B HER2-positive (19.2% vs. 14.2%, p = 0.0012) and HER2-positive (8.8% vs. 5.1%, p = 0.0009) were more common in patients with public health system coverage. Only 34% of patients were diagnosed by screening exams. Privately insured patients were more frequently diagnosed with stage I disease when compared to publicly insured patients; publicly insured patients had more stage III (33.5% vs. 14.7%; p-value < 0.0001) disease than privately insured ones. Breast cancer was detected by symptoms more frequently in publicly than in privately insured patients (74.2% vs 25.8%, respectively; p-value < 0.0001).

CONCLUSIONS

Patients with public health coverage were diagnosed with symptomatic disease, later stages and more aggressive subtypes when compared to privately insured patients.

Integrating biology and access to care in addressing breast cancer disparities: 25 years' research experience in the Carolina Breast Cancer Study

Purpose of Review

To review research on breast cancer mortality disparities, emphasizing research conducted in the Carolina Breast Cancer Study, with a focus on challenges and opportunities for integration of tumor biology and access characteristics across the cancer care continuum.

Recent Findings

Black women experience higher mortality following breast cancer diagnosis, despite lower incidence compared to white women. Biological factors, such as stage at diagnosis and breast cancer subtypes, play a role in these disparities. Simultaneously, social, behavioral, environmental, and access to care factors are important. However, integrated studies of biology and access are challenging and it is uncommon to have both data types available in the same study population. The central emphasis of Phase 3 of the Carolina Breast Cancer Study, initiated in 2008, was to collect rich data on biology (including germline and tumor genomics and pathology) and health care access in a diverse study population, with the long term goal of defining intervention opportunities to reduce disparities across the cancer care continuum.

Summary

Early and ongoing research from CBCS has identified important interactions between biology and access, leading to opportunities to build greater equity. However, sample size, population-specific relationships among variables, and complexities of treatment paths along the care continuum pose important research challenges. Interdisciplinary teams, including experts in novel data integration and causal inference, are needed to address gaps in our understanding of breast cancer disparities.

Identification of Distinct Heterogenic Subtypes and Molecular Signatures Associated with African Ancestry in Triple Negative Breast Cancer Using Quantified Genetic Ancestry Models in Admixed Race Populations

Triple negative breast cancers (TNBCs) are molecularly heterogeneous, and the link between their aggressiveness with African ancestry is not established. We investigated primary TNBCs for gene expression among self-reported race (SRR) groups of African American (AA, n = 42) and European American (EA, n = 33) women. RNA sequencing data were analyzed to measure changes in genome-wide expression, and we utilized logistic regressions to identify ancestry-associated gene expression signatures. Using SNVs identified from our RNA sequencing data, global ancestry was estimated. We identified 156 African ancestry-associated genes and found that, compared to SRR, quantitative genetic analysis was a more robust method to identify racial/ethnic-specific genes that were differentially expressed. A subset of African ancestry-specific genes that were upregulated in TNBCs of our AA patients were validated in TCGA data. In AA patients, there was a higher incidence of basal-like two tumors and altered TP53, NFB1, and AKT pathways. The distinct distribution of TNBC subtypes and altered oncologic pathways show that the ethnic variations in TNBCs are driven by shared genetic ancestry. Thus, to appreciate the molecular diversity of TNBCs, tumors from patients of various ancestral origins should be evaluated.

The Black identity, hair product use, and breast cancer scale

INTRODUCTION

Across the African Diaspora, hair is synonymous with identity. As such, Black women use a variety of hair products, which often contain more endocrine-disrupting chemicals than products used by women of other races. An emerging body of research is linking chemicals in hair products to breast cancer, but there is no validated instrument that measures constructs related to hair, identity, and breast health. The objective of this study was to develop and validate the Black Identity, Hair Product Use, and Breast Cancer Scale (BHBS) in a diverse sample of Black women to measure the social and cultural constructs associated with Black women's hair product use and perceived breast cancer risk.

METHODS

Participants completed a 27-item scale that queried perceptions of identity, hair products, and breast cancer risk. Principal Component Analyses (PCA) were conducted to establish the underlying component structures, and confirmatory factor analysis (CFA) was used to determine model fit.

RESULTS

Participants (n = 185) were African American (73%), African, and Caribbean Black women (27%) aged 29 to 64. PCA yielded two components that accounted for 61% of total variance. Five items measuring sociocultural perspectives about hair and identity loaded on subscale 1 and accounted for 32% of total variance (α = 0.82; 95% CI = 0.77-0.86). Six items assessing perceived breast cancer risk related to hair product use loaded on subscale 2 and accounted for 29% of total variance (α = 0.82 (95% CI = 0.74-0.86). CFA confirmed the two-component structure (Root Mean Square Error of Approximation = 0.03; Comparative Fit Index = 0.91; Tucker Lewis Index = 0.88).

CONCLUSIONS

The BHBS is a valid measure of social and cultural constructs associated with Black women's hair product use and perceived breast cancer risk. This scale is useful for studies that assess cultural norms in the context of breast cancer risk for Black women.

Race and delays in breast cancer treatment across the care continuum in the Carolina Breast Cancer Study

BACKGROUND

After controlling for baseline disease factors, researchers have found that black women have worse breast cancer survival, and this suggests that treatment differences may contribute to poorer outcomes. Delays in initiating and completing treatment are one proposed mechanism.

METHODS

Phase 3 of the Carolina Breast Cancer Study involved a large, population-based cohort of women with incident breast cancer. For this analysis, we included black women (n = 1328) and white women (n = 1331) with stage I to III disease whose treatment included surgery with or without adjuvant therapies. A novel treatment pathway grouping was used to benchmark the treatment duration (surgery only, surgery plus chemotherapy, surgery plus radiation, or all 3). Models controlled for the treatment pathway, age, and tumor characteristics and for demographic factors related to health care access. Exploratory analyses of the association between delays and cancer recurrence were performed.

RESULTS

In fully adjusted analyses, blacks had 1.73 times higher odds of treatment initiation more than 60 days after their diagnosis in comparison with whites (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.04-2.90). Black race was also associated with a longer treatment duration. Blacks were also more likely to be in the highest quartile of treatment duration (OR, 1.69; 95% CI, 1.41-2.02), even after adjustments for demographic and tumor characteristics (OR, 1.31; 95% CI, 1.04-1.64). A nonsignificant trend toward a higher recurrence risk was observed for patients with delayed initiation (hazard ratio, 1.44; 95% CI, 0.89-2.33) or the longest duration (hazard ratio, 1.17; 95% CI, 0.87-1.59).

CONCLUSIONS

Black women more often had delayed treatment initiation and a longer duration than whites receiving similar treatment. Interventions that target access barriers may be needed to improve timely delivery of care.

Endocrine Therapy Nonadherence and Discontinuation in Black and White Women

BACKGROUND

Differential use of endocrine therapy (ET) by race may contribute to breast cancer outcome disparities, but racial differences in ET behaviors are poorly understood.

METHODS

Women aged 20-74 years with a first primary, stage I-III, hormone receptor-positive (HR+) breast cancer were included. At 2 years postdiagnosis, we assessed nonadherence, defined as not taking ET every day or missing more than two pills in the past 14 days, discontinuation, and a composite measure of underuse, defined as either missing pills or discontinuing completely. Using logistic regression, we evaluated the relationship between race and nonadherence, discontinuation, and overall underuse in unadjusted, clinically adjusted, and socioeconomically adjusted models.

RESULTS

A total of 1280 women were included; 43.2% self-identified as black. Compared to white women, black women more often reported nonadherence (13.7% vs 5.2%) but not discontinuation (10.0% vs 10.7%). Black women also more often reported the following: hot flashes, night sweats, breast sensitivity, and joint pain; believing that their recurrence risk would not change if they stopped ET; forgetting to take ET; and cost-related barriers. In multivariable analysis, black race remained statistically significantly associated with nonadherence after adjusting for clinical characteristics (adjusted odds ratio = 2.72, 95% confidence interval = 1.75 to 4.24) and after adding socioeconomic to clinical characteristics (adjusted odds ratio = 2.44, 95% confidence interval = 1.50 to 3.97) but was not independently associated with discontinuation after adjustment. Low recurrence risk perception and lack of a shared decision making were strongly predictive of ET underuse across races.

CONCLUSIONS

Our results highlight important racial differences in ET-adherence behaviors, perceptions of benefits/harms, and shared decision making that may be targeted with culturally tailored interventions.

Health and Racial Disparity in Breast Cancer

Breast cancer is the most common noncutaneous malignancy and the second most lethal form of cancer among women in the United States. It currently affects more than one in ten women worldwide. The chance for a female to be diagnosed with breast cancer during her lifetime has significantly increased from 1 in 11 women in 1975 to 1 in 8 women (Altekruse, SEER Cancer Statistics Review, 1975-2007. National Cancer Institute, Bethesda, 2010). This chance for a female of being diagnosed with cancer generally increases with age (Howlader et al, SEER Cancer Statistics Review, 1975-2010. National Cancer Institute, Bethesda, 2013). Fortunately, the mortality rate from breast cancer has decreased in recent years due to increased emphasis on early detection and more effective treatments in the White population. Although the mortality rates have declined in some ethnic populations, the overall cancer incidence among African American and Hispanic population has continued to grow. The goal of the work presented in this book chapter is to highlight similarities and differences in breast cancer morbidity and mortality rates among non-Hispanic white and non-Hispanic black populations. This book chapter also provides an overview of breast cancer, racial/ethnic disparities in breast cancer, breast cancer incidence and mortality rate linked to hereditary, major risk factors of breast cancer among minority population, breast cancer treatment, and health disparity. A considerable amount of breast cancer treatment research have been conducted, but with limited success for African Americans compared to other ethnic groups. Therefore, new strategies and approaches are needed to promote breast cancer prevention, improve survival rates, reduce breast cancer mortality, and ultimately improve the health outcomes of racial/ethnic minorities. In addition, it is vital that leaders and medical professionals from minority population groups be represented in decision-making in research so that racial disparity in breast cancer can be well-studied, fully addressed, and ultimately eliminated in breast cancer.

TP53 protein levels, RNA-based pathway assessment, and race among invasive breast cancer cases

Mutations in tumor suppressor TP53 have been inconsistently linked to breast cancer risk factors and survival. Immunohistochemistry (IHC) staining, a primary clinical means of TP53 mutation determination, only detects mutations that facilitate protein accumulation (e.g., missense mutations). RNA-based pathway methods capture functional status and may aid in understanding the role of TP53 function in racial disparities of breast cancer. TP53 status was assessed among invasive breast cancer cases from the Carolina Breast Cancer Study (CBCS) (2008–2013) using IHC and an established RNA-based TP53 signature (CBCS and The Cancer Genome Atlas (TCGA)). Frequency of TP53 status (IHC, RNA-based) was estimated in association with tumor characteristics, PAM50 intrinsic subtype, age, and race using relative frequency differences (RFDs) and 95% confidence intervals (95% CI) as the measure of association. Approximately 60% of basal-like tumors were TP53 protein positive (IHC), while nearly 100% were TP53 mutant-like (RNA). Luminal A tumors had low frequency of TP53 positivity (IHC: 7.9%) and mutant-like status (RNA: 1.7%). Mutant-like TP53 (RNA) was strongly associated with age ≤50 years, high tumor grade, advanced stage of disease, large tumor size, and basal-like and HER2 intrinsic subtypes. Black race was strongly associated with TP53 mutant-like status (RNA) (RFD: 24.8%, 95% CI: 20.5, 29.0) even after adjusting for age, grade, stage (RFD: 11.3%; 95% CI: 7.6, 15.0). Associations were attenuated and non-significant when measured by IHC. IHC-based TP53 status is an insensitive measurement of TP53 functional status. RNA-based methods suggest a role for TP53 in tumor prognostic features and racial disparities.

RNA-based assays offer a more sensitive and clinically informative measure of mutations in the tumor suppressor TP53 among women with invasive breast cancer than do immunohistochemistry techniques that can only detect altered proteins. Using tumor samples from more than 1000 women enrolled in the Carolina Breast Cancer Study (CBCS), Melissa Troester from the University of North Carolina at Chapel Hill, USA, and coworkers assessed the functional status of TP53 via both classical immunohistochemistry methods and an RNA-based test of expression levels among 52 TP53-dependent genes. The results of the RNA analysis were strongly associated with younger age-of-onset, higher grade tumors, more advanced stage disease, larger tumor size, aggressive cancer subtypes and race—with more black women harboring TP53 mutant-like tumors than white women. By comparison, these associations were weaker or non-significant when using immunohistochemistry-based tests.

Racial disparity in breast cancer: can it be mattered for prognosis and therapy

Breast cancer (BC) has emerged as a deadly disease that affects the lives of millions of women worldwide. It is the second leading cause of cancer-related deaths in the United States. Advancements in BC screening, preventive measures and treatment have resulted in significant decline in BC related deaths. However, unacceptable levels of racial disparity have been consistently reported, especially in African-American (AA) women compared to European American (EA). AA women go through worse prognosis, shorter survival time and higher mortality rates, despite higher cancer incidence reported in EA. These disparities are independent of socioeconomic status, access to healthcare or age, or even the stage of BC. Recent race-specific genetic and epigenetic studies have reported biological causes, which form the crux of this review. However, the developments are just the tip of the iceberg. Prioritizing primary research towards studying race-specific tumor microenvironment and biological composition of the host system in delineating the cause of these disparities is utmost necessary to ameliorate the disparity and design appropriate diagnosis/treatment regimen for AA women suffering from BC. In this review article, we discuss emerging trends and exciting discoveries that reveal how genetic/epigenetic circuitry contributed to racial disparity and discussed the strategies that may help in future therapeutic development.

Ethnicity and breast cancer characteristics in Kenya

PURPOSE

There are no published data from specific regions of sub-Saharan Africa describing the clinical and pathological characteristics and molecular subtypes of invasive breast cancer by ethnic group. The purpose of this study was to investigate these characteristics among the three major ethno-cultural groupings in Kenya.

METHODS

The study included women with pathologically confirmed breast cancer diagnosed between March 2012 and May 2015 at 11 hospitals throughout Kenya. Sociodemographic, clinical, and reproductive data were collected by questionnaire, and pathology review and immunohistochemistry were performed centrally.

RESULTS

The 846 cases included 661 Bantus (78.1%), 143 Nilotes (16.9%), 19 Cushites (2.3%), and 23 patients of mixed ethnicity (2.7%). In analyses comparing the two major ethnic groups, Bantus were more educated, more overweight, had an older age at first birth, and had a younger age at menopause than Nilotes (p < 0.05 for all comparisons). In analyses restricted to definitive surgery specimens, there were no statistically significant differences in tumor characteristics or molecular subtypes by ethnicity, although the Nilote tumors tended to be larger (OR for ≥ 5 cm vs. < 2 cm: 3.86, 95% CI 0.77, 19.30) and were somewhat more likely to be HER2 enriched (OR for HER2 enriched vs. Luminal A/B: 1.41, 95% CI 0.79, 2.49).

CONCLUSION

This case series showed no significant differences in breast cancer tumor characteristics or molecular subtypes, but significant differences in sociodemographic characteristics and reproductive factors, among the three major ethnic groups in Kenya. We suggest further evaluation of ethnic differences in breast cancer throughout the genetically and culturally diverse populations of sub-Saharan Africa.

Centrosome amplification: a suspect in breast cancer and racial disparities

The multifaceted involvement of centrosome amplification (CA) in tumorigenesis is coming into focus following years of meticulous experimentation, which have elucidated the powerful abilities of CA to promote cellular invasion, disrupt stem cell division, drive chromosomal instability (CIN) and perturb tissue architecture, activities that can accelerate tumor progression. Integration of the extant in vitro, in vivo and clinical data suggests that in some tissues CA may be a tumor-initiating event, in others a consequential 'hit' in multistep tumorigenesis, and in some others, non-tumorigenic. However, in vivo data are limited and primarily focus on PLK4 (which has CA-independent mechanisms by which it promotes aggressive cellular phenotypes). In vitro breast cancer models suggest that CA can promote tumorigenesis in breast cancer cells in the setting of p53 loss or mutation, which can both trigger CA and promote cellular tolerance to its tendency to slow proliferation and induce aneuploidy. It is thus our perspective that CA is likely an early hit in multistep breast tumorigenesis that may sometimes be lost to preserve aggressive karyotypes acquired through centrosome clustering-mediated CIN, both numerical and structural. We also envision that the robust link between p53 and CA may underlie, to a considerable degree, racial health disparity in breast cancer outcomes. This question is clinically significant because, if it is true, then analysis of centrosomal profiles and administration of centrosome declustering drugs could prove highly efficacious in risk stratifying breast cancers and treating African American (AA) women with breast cancer.

Breast Cancer Disparities at Home and Abroad: A Review of the Challenges and Opportunities for System-Level Change

Sizeable disparities exist in breast cancer outcomes, both between Black and White patients in the United States, and between patients in the United States and other high-income countries compared with low- and middle-income countries (LMIC). In both settings, health system factors are key drivers of disparities. In the United States, Black women are more likely to die of breast cancer than Whites and have poorer outcomes, even among patients with similar stage and tumor subtype. Over-representation of higher risk "triple-negative" breast cancers contributes to breast cancer mortality in Black women; however, the greatest survival disparities occur within the good-prognosis hormone receptor-positive (HR+) subtypes. Disparities in access to treatment within the complex U.S. health system may be responsible for a substantial portion of these differences in survival. In LMICs, breast cancer mortality rates are substantially higher than in the United States, whereas incidence continues to rise. This mortality burden is largely attributable to health system factors, including late-stage presentation at diagnosis and lack of availability of systemic therapy. This article will review the existing evidence for how health system factors in the United States contribute to breast cancer disparities, discuss methods for studying the relationship of health system factors to racial disparities, and provide examples of health system interventions that show promise for mitigating breast cancer disparities. We will then review evidence of global breast cancer disparities in LMICs, the treatment factors that contribute to these disparities, and actions being taken to combat breast cancer disparities around the world. Clin Cancer Res; 23(11); 2655-64. ©2017 AACRSee all articles in this CCR Focus section, "Breast Cancer Research: From Base Pairs to Populations."

Assessing the Racial and Ethnic Disparities in Breast Cancer Mortality in the United States

Breast cancer is the second leading cause of cancer related deaths among women aged 40-55 in the United States and currently affects more than one in ten women worldwide. It is also one of the most diagnosed cancers in women both in wealthy and poor countries. Fortunately, the mortality rate from breast cancer has decreased in recent years due to increased emphasis on early detection and more effective treatments in White population. Although the mortality rates have declined in some ethnic populations, the overall cancer incidence among African American and Hispanic populations has continued to grow. The goal of the present review article was to highlight similarities and differences in breast cancer morbidity and mortality rates primarily among African American women compared to White women in the United States. To reach our goal, we conducted a search of articles in journals with a primary focus on minority health, and authors who had published articles on racial/ethnic disparity related to breast cancer patients. A systematic search of original research was conducted using MEDLINE, PUBMED and Google Scholar databases. We found that racial/ethnic disparities in breast cancer may be attributed to a large number of clinical and non-clinical risk factors including lack of medical coverage, barriers to early detection and screening, more advanced stage of disease at diagnosis among minorities, and unequal access to improvements in cancer treatment. Many African American women have frequent unknown or unstaged breast cancers than White women. These risk factors may explain the differences in breast cancer treatment and survival rate between African American women and White women. New strategies and approaches are needed to promote breast cancer prevention, improve survival rate, reduce breast cancer mortality, and ultimately improve the health outcomes of racial/ethnic minorities.

Racial Differences in Cancer Susceptibility and Survival: More Than the Color of the Skin?

Epidemiological studies point to race as a determining factor in cancer susceptibility. In US registries recording cancer incidence and survival by race (distinguishing 'black versus white'), individuals of African ancestry have a globally increased risk of malignancies compared with Caucasians and Asian Americans. Differences in socioeconomic status and health-care access play a key role. However, the lesser disease susceptibility of Hispanic populations with comparable lifestyles and socioeconomic status as African Americans (Hispanic paradox) points to the concomitant importance of genetic determinants. Here, we overview the molecular basis of racial disparity in cancer susceptibility ranging from genetic polymorphisms and cancer-driver gene mutations to obesity, chronic inflammation, and immune responses. We discuss implications for race-adapted cancer screening programs and clinical trials to reduce disparities in cancer burden.

Breast cancer survival disparity between African American and Caucasian women in Arkansas: A race-by-grade analysis

Despite progress in breast cancer treatment, disparity persists in survival time between African American (AA) and Caucasian women in the US. Tumor stage and tumor grade are the major prognostic factors that define tumor aggressiveness and contribute to racial disparity between AA and Caucasian women. Studying the interaction of race with tumor grade or stage may provide further insights into the role of intrinsic biological aggressiveness in disecting the AA-Caucasian survival disparity. Therefore, the current study was performed to evaluate the interaction of race with tumor grade and stage at diagnosis regarding survival in a cohort of patients treated at the Winthrop P. Rockefeller Cancer Institute of the University of Arkansas for Medical Sciences (Little Rock, AR, USA). The cohort included 1,077 patients, 208 (19.3%) AA and 869 (80.7%) Caucasian, diagnosed with breast cancer between January 1997 and December 2005. Kaplan-Meier survival plots were generated and Cox regressions were performed to analyze the associations of race with breast cancer-specific survival time. Over a mean follow-up time of 1.5 years, AA women displayed increased mortality risk due to breast cancer-specific causes [hazard ratio (HR), 1.74; 95% confidence interval (CI), 1.23–2.46]. The magnitude of racial disparity varied strongly with tumor grade (race-x-grade interaction; P<0.001). No significant interaction was observed between race and tumor stage or race and age at diagnosis. Among women diagnosed with grade I tumors, the race disparity in survival time after controlling for tumor stage and age was strong (HR, 9.07; 95% CI, 2.11–38.95), but no significant AA-Caucasian disparity was observed among women with higher-grade tumors. The data suggest that, when diagnosed with grade I breast cancer, AA may experience poorer survival outcomes compared with Caucasian patients, regardless of tumor stage or age. The findings potentially provide significant clinical and public health implications and justify further investigation.

Breast cancers from black women exhibit higher numbers of immunosuppressive macrophages with proliferative activity and of crown-like structures associated with lower survival compared to non-black Latinas and Caucasians

Racial disparities in breast cancer incidence and outcome are a major health care challenge. Patients in the black race group more likely present with an early onset and more aggressive disease. The occurrence of high numbers of macrophages is associated with tumor progression and poor prognosis in solid malignancies. Macrophages are observed in adipose tissues surrounding dead adipocytes in "crown-like structures" (CLS). Here we investigated whether the numbers of CD163+ tumor-associated macrophages (TAMs) and/or CD163+ CLS are associated with patient survival and whether there are significant differences across blacks, non-black Latinas, and Caucasians. Our findings confirm that race is statistically significantly associated with the numbers of TAMs and CLS in breast cancer, and demonstrate that the highest numbers of CD163+ TAM/CLS are found in black breast cancer patients. Our results reveal that the density of CD206 (M2) macrophages is a significant predictor of progression-free survival univariately and is also significant after adjusting for race and for HER2, respectively. We examined whether the high numbers of TAMs detected in tumors from black women were associated with macrophage proliferation, using the Ki-67 nuclear proliferation marker. Our results reveal that TAMs actively divide when in contact with tumor cells. There is a higher ratio of proliferating macrophages in tumors from black patients. These findings suggest that interventions based on targeting TAMs may not only benefit breast cancer patients in general but also serve as an approach to remedy racial disparity resulting in better prognosis patients from minority racial groups.

Breast Cancer Subtype Variation by Race and Ethnicity in a Diverse Population in British Columbia

BACKGROUND

Breast cancer subtypes occur differentially across different racial and ethnic groups. However, their distribution within a multicultural population is unknown.

MATERIALS AND METHODS

Patients with invasive breast cancer newly diagnosed in 2006 and referred to the British Columbia Cancer Agency were identified from the Breast Cancer Outcomes Unit database. Race/ethnicity data were abstracted from a patient-completed health assessment questionnaire completed at the initial consultation, and grouped as white, East Asian, Aboriginal, South Asian, Southeast Asian, and other. Breast cancer subtypes were created using available data on estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status.

RESULTS

A total of 1829 women had complete data. Of these women, 73% were white, 8% were East Asian, 4% Aboriginal, 3% South Asian, 3% Southeast Asian, and 3% other. The median age at diagnosis was 60 years; the youngest were Southeast Asian (51 years) and the oldest were white (60 years; P < .001). The overall ER positivity rate was 81%, highest in East Asian women (89%) and lowest in South Asian women (73%). The HER2 positivity rate was 16% for all patients and was highest in the South Asian (28%), Southeast Asian (28%), and Aboriginal (24%) women and lowest in the white women (14%; P < .001). Triple-negative (ER-, PR-, and HER2-negative) breast cancer was uncommon in East Asian women (5%) but more common in South Asian women (19%; P < .001). The 5-year breast cancer-specific survival was 90% (95% confidence interval, 89%-92%), with no significant difference among the racial/ethnic groups (P = .136).

CONCLUSION

Breast cancer subtypes varied by race/ethnicity in our cross-sectional cohort of a multicultural population, suggesting that race/ethnicity plays a significant role in the biology of invasive breast cancer.

Racial disparity in survival from early breast cancer in the department of defense healthcare system

BACKGROUND

Racial disparity is often identified as a factor in survival from breast cancer in the United States. Current data regarding survival in patients treated in the Department of Defense Military Healthcare System is lacking.

METHODS

The Department of Defense Automated Central Tumor Registry (ACTUR) was queried for all women diagnosed with Stage I or II breast cancer from January 1, 1996 through December 31, 2008. Statistical analyses evaluated demographics, surgical treatment, tumor stage, and survival rates.

RESULTS

There were 8,890 patients meeting inclusion criteria. Patients who were younger, Asian American (versus white or black), lower T and/or N stage had significantly improved survival rates. Interestingly, white and black patients demonstrated similar survival in this study. Patients with a longer period of time between diagnosis and treatment had no decrement in survival. As would be expected, patients with a longer recurrence free period enjoyed longer survival.

CONCLUSIONS

Survival from early stage breast cancer is equivalent between white and black patients in the Department of Defense Healthcare System. This finding is contrary to reports from our civilian counterparts and may be indicative of improved access to care and overall improved cancer surveillance.

Ancestry dependent DNA methylation and influence of maternal nutrition

There is extensive variation in DNA methylation between individuals and ethnic groups. These differences arise from a combination of genetic and non-genetic influences and potential modifiers include nutritional cues, early life experience, and social and physical environments. Here we compare genome-wide DNA methylation in neonatal cord blood from African American (AA; N = 112) and European American (EA; N = 91) participants of the CANDLE Study (Conditions Affecting Neurocognitive Development and Learning in Early Childhood). Our goal is to determine if there are replicable ancestry-specific methylation patterns that may implicate risk factors for diseases that have differential prevalence between populations. To identify the most robust ancestry-specific CpG sites, we replicate our results in lymphoblastoid cell lines from Yoruba African and CEPH European panels of HapMap. We also evaluate the influence of maternal nutrition--specifically, plasma levels of vitamin D and folate during pregnancy--on methylation in newborns. We define stable ancestry-dependent methylation of genes that include tumor suppressors and cell cycle regulators (e.g., APC, BRCA1, MCC). Overall, there is lower global methylation in African ancestral groups. Plasma levels of 25-hydroxy vitamin D are also considerably lower among AA mothers and about 60% of AA and 40% of EA mothers have concentrations below 20 ng/ml. Using a weighted correlation analysis, we define a network of CpG sites that is jointly modulated by ancestry and maternal vitamin D. Our results show that differences in DNA methylation patterns are remarkably stable and maternal micronutrients can exert an influence on the child epigenome.

Associations of hormone-related factors with breast cancer risk according to hormone receptor status among white and African American women

BACKGROUND

Causes of racial disparities in breast cancer incidence and mortality between white and African American women remain unclear. This study evaluated associations of menstrual and reproductive factors with breast cancer risk by race and cancer subtypes.

PATIENTS AND METHODS

Included in the study were 1866 breast cancer cases and 2306 controls recruited in the Nashville Breast Health Study, a population-based case-control study. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

African American women were more likely to have estrogen receptor-negative (ER(-)), progesterone receptor-negative (PR(-)), and triple-negative (ER(-)PR(-)HER2(-)) breast cancer than white women. Age at menarche (≥ 14 years) and multiparity (≥ 3 live births) were inversely associated with ER(+) tumors only, whereas late age at first live birth (> 30 years) and nulliparity were associated with elevated risk; such associations were predominantly seen in white women (OR = 0.70, 95% CI = 0.55-0.88; OR = 0.72, 95% CI = 0.56-0.92; OR = 1.42, 95% CI = 1.13-1.79; OR = 1.32, 95% CI = 1.06-1.63, respectively). Age at menopause between 47 and 51 years was associated with elevated risk of ER(-) tumors in both white and African American women. Among women who had natural menopause, positive association between ever-use of hormone replacement therapy and breast cancer risk was seen in white women only (OR = 1.39, 95% CI = 1.03-1.87).

CONCLUSION

This study suggests that certain hormone-related factors are differentially associated with risk of breast cancer subtypes, and these associations also differ by race.

A phase 2 study of 16α-[18F]-fluoro-17β-estradiol positron emission tomography (FES-PET) as a marker of hormone sensitivity in metastatic breast cancer (MBC)

PURPOSE

16α-[(18)F]-fluoro-17β-estradiol positron emission tomography (FES-PET) quantifies estrogen receptor (ER) expression in tumors and may provide diagnostic benefit.

PROCEDURES

Women with newly diagnosed metastatic breast cancer (MBC) from an ER-positive primary tumor were imaged before starting endocrine therapy. FES uptake was evaluated qualitatively and quantitatively, and associated with response and with ER expression.

RESULTS

Nineteen patients underwent FES imaging. Fifteen had a biopsy of a metastasis and 15 were evaluable for response. Five patients had quantitatively low FES uptake, six had at least one site of qualitatively FES-negative disease. All patients with an ER-negative biopsy had both low uptake and at least one site of FES-negative disease. Of response-evaluable patients, 2/2 with low FES standard uptake value tumors had progressive disease within 6 months, as did 2/3 with qualitatively FES-negative tumors.

CONCLUSIONS

Low/absent FES uptake correlates with lack of ER expression. FES-positron emission tomography can help identify patients with endocrine resistant disease and safely measures ER in MBC.

Differences in gene and protein expression and the effects of race/ethnicity on breast cancer subtypes

BACKGROUND

Differences in gene or protein expression patterns between breast cancers according to race/ethnicity and cancer subtype.

METHODS

Transcriptional profiling was performed using Affymetrix HG-U133A platform in 376 patients and reverse phase protein array analysis (RPPA) was done for 177 proteins in 255 patients from a separate cohort. Unsupervised clustering was conducted, as well as supervised comparison by race and tumor subtype. Standard statistical methods, BRB-Array tools, and Ingenuity Pathways software packages were used to analyze the data.

RESULTS

Median age was 50 years in both the cohorts. In the RPPA cohort, 54.5% of the tumors were hormone receptor-positive (HR-positive), 20.7% HER2-positive, and 24.71% triple-negative (TNBC). One hundred and forty-seven (57.6%), 47 (18.43%), and 46 (18.1%) of the patients were White, Hispanic, and Black, respectively. Unsupervised hierarchical clustering of the protein expression data showed no distinct clusters by race (P values were 0.492, 0.489, and 0.494 for the HR-positive, HER2-positive, and TNBC tumors respectively). In the gene expression cohort, 54.2% of the tumors were HR-positive, 16.5% HER2-positive, and 29.3% TNBC. Two hundred and sixteen (57.5%), 111 (29.52%), and 32 (8.52%) patients were White, Hispanic, and Black, respectively. No probe set with a false discovery rate (FDR) of <0.05 showed an association with race by breast cancer subtype; similar results were obtained using pathway and gene set enrichment analysis methods.

CONCLUSIONS

We did not detect a significant variation in RNA or protein expression comparing different race/ethnicity groups of women with breast cancer.

IMPACT

More research on the complex network of factors that result in outcomes differences among race/ethnicities is needed.

Disparities in breast cancer treatment and outcomes: biological, social, and health system determinants and opportunities for research

Racial disparities in breast cancer mortality have been widely documented for several decades and persist despite advances in receipt of mammography across racial groups. This persistence leads to questions about the roles of biological, social, and health system determinants of poor outcomes. Cancer outcomes are a function not only of innate biological factors but also of modifiable characteristics of individual behavior and decision making as well as characteristics of patient-health system interaction and the health system itself. Attempts to explain persistent racial disparities have mostly been limited to discussion of differences in insurance coverage, socioeconomic status, tumor stage at diagnosis, comorbidity, and molecular subtype of the tumor. This article summarizes existing literature exploring reasons for racial disparities in breast cancer mortality, with an emphasis on treatment disparities and opportunities for future research. Because breast cancer care requires a high degree of multidisciplinary team collaboration, ensuring that guideline recommended treatment (such as endocrine therapy for hormone receptor positive patients) is received by all racial/ethnic groups is critical and requires coordination across multiple providers and health care settings. Recognition that variation in cancer care quality may be correlated with race (and socioeconomic and health system factors) may assist policy makers in identifying strategies to more equally distribute clinical expertise and health infrastructure across multiple user populations.

Disparities in breast cancer outcomes between Caucasian and African American women: a model for describing the relationship of biological and nonbiological factors

Breast cancer is the most common malignancy in women in the United States but significant disparities exist for African American women compared to Caucasian women. African American women present with breast cancer at a younger age and with a greater incidence under the age of 50 years, develop histologically more aggressive tumors that are at a more advanced stage at presentation, and have a worse disease-free and overall survival than Caucasian women. The biological characteristics of the primary tumor play an important role in determining the outcome of the disparity, and significant differences have been identified between African American and Caucasian breast cancer in steroid receptor and growth factor receptor content, mutations in cell cycle components, chromosomal abnormalities, and tumor suppressor and other cancer genes. The consequences of the biological factors are influenced by a variety of nonbiological factors, including socioeconomic, health care access, reproductive, and confounding factors. The nonbiological factors may act directly to enhance (or inhibit) the consequences of the biological changes, indirectly to facilitate outcome of the disparity, or as a cofounding factor, driving the association between the biological factors and the disparity. The prevention and management of the disparities will require an understanding of the relationship of biological and nonbiological factors. The present review was undertaken to promote this understanding by describing the biological basis of the four major disparities - early age of onset, more advanced stage of disease, more aggressive histologic changes, and worse survival - and the important relationship to the nonbiological factors. A model is proposed to provide a comprehensive view of this relationship, with the goal of facilitating an understanding of each disparity and the issues that need to be addressed to eliminate the disparity.

Cell Proliferation (KI-67) Expression Is Associated with Poorer Prognosis in Nigerian Compared to British Breast Cancer Women

Background. Black women with breast cancer (BC) in Nigeria have higher mortality rate compared with British women. This study investigated prognostic features of cell proliferation biomarker (Ki-67) in Nigerian breast cancer women. Materials and Methods. The protein expression of Ki-67 was investigated in series of 308 Nigerian women, prepared as a tissue microarray (TMA), using immunohistochemistry. Clinic-pathological parameters, biomarkers, and patient outcome of tumours expressing Ki-67 in Nigerian women were correlated with UK grade-matched series. Results. A significantly larger proportion of breast tumours from Nigerian women showed high Ki-67 expression. Those tumours were significantly correlated with negative expression of the steroid hormone receptors (ER and PgR), p21, p27, E-cadherin, BRCA-1, and Bcl-2 (all P < 0.001), but positively associated with EGFR (P = 0.003), p53, basal cytokeratins: CK56, CK14, triple negative, and basal phenotype using Nielsen's classification (all P < 0.001) compared to UK women. Multivariate analyses showed that race was also associated with BCSS independent of tumour size, lymph node status, and ER status. Conclusion. Ki-67 expression was observed to have contributed to the difference in the BCSS in Nigerian compared with British BC women. Therefore, targeting Ki-67 in the indigenous black women with BC might improve the patient outcome in the black women with BC.

Molecular characteristics and prognostic features of breast cancer in Nigerian compared with UK women

Although breast cancer (BC) incidence is lower in African-American women compared with White-American, in African countries such as Nigeria, BC is a common disease. Nigerian women have a higher risk for early-onset, with a high mortality rate from BC, prompting speculation that risk factors could be genetic and the molecular portrait of these tumours are different to those of western women. In this study, 308 BC samples from Nigerian women with complete clinical history and tumour characteristics were included and compared with a large series of BC from the UK as a control group. Immunoprofile of these tumours was characterised using a panel of 11 biomarkers of known relevance to BC. The immunoprofile and patients' outcome were compared with tumour grade-matched UK control group. Nigerian women presenting with BC were more frequently premenopausal, and their tumours were characterised by large primary tumour size, high tumour grade, advanced lymph node stage, and a higher rate of vascular invasion compared with UK women. In the grade-matched groups, Nigerian BC showed over representation of triple-negative and basal phenotypes and BRCA1 deficiency BC compared with UK women, but no difference was found regarding HER2 expression between the two series. Nigerian women showed significantly poorer outcome after development of BC compared with UK women. This study demonstrates that there are possible genetic and molecular differences between an indigenous Black population and a UK-based series. The basal-like, triple negative and BRCA1 dysfunction groups of tumours identified in this study may have implications in the development of screening programs and therapies for African patients and families that are likely to have a BRCA1 dysfunction, basal like and triple negative.

Factors associated with receipt of breast cancer adjuvant chemotherapy in a diverse population-based sample

PURPOSE

Disparities in receipt of adjuvant chemotherapy may contribute to higher breast cancer fatality rates among black and Hispanic women compared with non-Hispanic whites. We investigated factors associated with receipt of chemotherapy in a diverse population-based sample.

PATIENTS AND METHODS

Women diagnosed with breast cancer between August 2005 and May 2007 (N = 3,252) and reported to the Detroit, Michigan, or Los Angeles County Surveillance, Epidemiology, and End Results (SEER) registry were recruited to complete a survey. Multivariable analyses examined factors associated with chemotherapy receipt.

RESULTS

The survey was sent to 3,133 patients; 2,290 completed a survey (73.1%), and 1,403 of these patients were included in the analytic sample. In multivariable models, disease characteristics were significantly associated with the likelihood of receiving chemotherapy. Low-acculturated Hispanics were more likely to receive chemotherapy than non-Hispanic whites (odds ratio [OR], 2.00; 95% CI, 1.31 to 3.04), as were high-acculturated Hispanics (OR, 1.43; 95% CI, 1.03 to 1.98). Black women were less likely to receive chemotherapy than non-Hispanic whites, but the difference was not significant (OR, 0.83; 95% CI, 0.64 to 1.08). Increasing age (even in women age < 50 years) and Medicaid insurance were associated with lower rates of chemotherapy receipt.

CONCLUSION

In this population-based sample, disease characteristics were strongly associated with receipt of chemotherapy, indicating that clinical benefit guides most treatment decisions. We found no compelling evidence that black women and Hispanics receive chemotherapy at lower rates. Interventions that address chemotherapy use rates according to age and insurance status may improve quality of systemic treatment.

A population-based study of Kurdish breast cancer in northern Iraq: hormone receptor and HER2 status. A comparison with Arabic women and United States SEER data

Background

Hormone receptor (HR) and HER2 expression predict the therapeutic response and prognosis of breast cancer. In the Middle-East, breast cancer is diagnosed at a young age, and Arabic women are reported to have a low frequency of HR positive tumors. This study investigates HR and HER2 expression among Kurdish and Arabic women.

Methods

During 2008–2010, the Sulaimaniyah Directorate of Health records identified 514 Sulaimaniyah Kurdish women, 227 Kurdish women of other Governates, and 83 Arabic women with a first diagnosis of breast cancer. The breast cancers of 432 women had immunohistochemistry (IHC) performed for estrogen and progesterone receptors (ER and PR) and HER2. Age specific and age standardized incidence rates were calculated for Sulaimaniyah Kurds. Results were compared with Egypt and with United States (US) SEER data.

Results

The median patient age was 46 years and 60.4% were < 50 years old. Tumors of 65.2% of women were ER+/HER2- with the rate increasing to 78.3% in patients ≥ 60 years old in proportions similar to US whites. The total annual age standardized incidence for breast cancer among Sulaimaniyah Kurds was 40.5/100,000 women, a rate similar to Egypt but much lower than the US. By HR/HER2 subtype, the highest age specific incidence rates were 16.4 and 45.4/100,000 for ER+/PR+/HER2- tumors in women < 50 or ≥ 50 years old, respectively (US whites: 37.7 and 226.1/100,000). Tumors of 20.4% of Sulaimaniyah women were HER2+ with annual incidence rates for ER-/PR-/HER2+ tumors of women <50 or ≥ 50 years old being 4.0 and 6.3/100,000 (US whites: 3.2 and 14.4/100,000). No significant differences in ER or HER2 status were found between Kurdish and Arabic patients.

Conclusions

Compared to the US, low age standardized and age specific breast cancer incidence rates were found in Kurdish women; nevertheless, the proportional expression of HR and HER2 for both Kurds and Arabs was comparable to that of US white women. The great majority of the breast cancer was ER+/HER2- and should respond to anti-estrogen therapy.

Differential expression of breast cancer-associated genes between stage- and age-matched tumor specimens from African- and Caucasian-American Women diagnosed with breast cancer

Background

Recent studies suggest that the poorer breast cancer outcome observed in African-American women (AAW) may, in part, result from underlying molecular factors. The purpose of this study was to investigate gene expression differences between Caucasian-American women (CAW) and AAW that may contribute to this poorer prognosis.

Methods

The expression of 84 genes involved in breast carcinoma prognosis, response to therapy, estrogen signaling, and tumor aggressiveness was assessed in age- and stage-matched CAW and AAW paraffin-embedded breast cancer specimens. The Wilcoxon–Mann–Whitney Test was used to identify genes with a significant difference in expression between CAW and AAW. To determine if the differentially expressed genes could segregate between the CAW and AAW, we performed semi-supervised principal component analysis (SSPCA).

Results

Twenty genes were differentially expressed between AAW and CAW. SSPCA incorporating these 20 genes segregated AAW and CAW into two distinct groups. AAW were significantly (p < 0.05) more likely to display aberrations in G₁/S cell-cycle regulatory genes, decreased expression of cell-adhesion genes, and low to no expression of ESR1, PGR, ERBB2 and estrogen pathway targets.

Conclusions

The gene expression differences identified between AAW and CAW may contribute to more aggressive disease, resistance to therapy, enhanced metastatic potential and poor clinical outcome. These findings support the hypothesis that breast cancer specimens collected from AAW display distinct gene expression differences compared to similar tissues obtained from CAW. Additional population-based studies are necessary to determine if these gene expression variations contribute to the highly aggressive and treatment-resistant breast cancer phenotype frequently observed in AAW.

Race and the prognostic influence of p53 in women with breast cancer

BACKGROUND

Prior study suggests that p53 status behaves as an independent marker of prognosis in African American (AA) women with breast cancer. We investigate whether the influence of p53 is unique to AAs or is present in other race/ethnic groups, and how this compares with known prognostic factors.

METHODS

Cox regression models [hazard ratios (HRs), 95% confidence intervals (CIs)] were used to select and evaluate factors prognostic for all-cause mortality in 331 AA and 203 non-AA consecutively treated women.

RESULTS

Statistically significant baseline prognostic factors were as follows. For AAs: stage [(III/I) HR 5.57; 95% CI 3.08-10.09], grade [(higher/low) HR 1.55; 95% CI 1.14-2.11], estrogen receptor (ER)/progesterone receptor (PR) status [(-/+) HR 2.01; 95% CI 1.38-2.93], triple negative (ER-, PR-, HER2-) subtype [(+/-) HR 1.95; 95% CI 1.33-2.85], and p53 status [(+/-) HR 1.69; 95% CI 1.10-2.58]. For non-AAs: stage [HR 11.93; 95% CI 2.80-50.84], grade [HR 1.61; 95% CI 0.96-2.71], and ER/PR status [HR 2.13; 95% CI 1.19-3.81]. There was a differential effect of race within p53 groups (P=0.05) and in multivariate modeling p53-positive status remained an adverse prognostic factor in AAs only [HR 1.82; 95% CI 1.04-3.17]. Compared to non-AAs, 5-year unadjusted survival was worse for AAs overall (73.4% vs. 63.6%; P=0.032), and also for AAs with p53-positive status (80.3% vs. 54.2%; P=0.016), but not for AAs with p53-negative disease (68.4% vs. 67.9%; P=0.81).

CONCLUSIONS

Among women with breast cancer of different race/ethnicity, an adverse prognostic effect as a result of p53 positivity was only observed in AA women.

A cluster randomized controlled trial to increase breast cancer screening among African American women: the black cosmetologists promoting health program

BACKGROUND

African American women have disproportionately higher rates of breast cancer mortality than all other ethnic groups, thus highlighting the importance of promoting early detection.

METHODS

African American women (N = 984) from San Diego, California, participated in a randomized controlled trial testing the efficacy of breast cancer education sessions offered in beauty salons. Cosmetologists received ongoing support, training, and additional culturally aligned educational materials to help them engage their clients in dialogues about the importance of breast cancer early detection. Posters and literature about breast cancer early detection were displayed throughout the salons and cosmetologists used synthetic breast models to show their clients how breast cancer lumps might feel. Participants in the control group received a comparable diabetes education program. Baseline and 6-month follow-up surveys were administered to evaluate changes in women's breast cancer knowledge, attitudes, and screening behaviors.

RESULTS

This intervention was well received by the participants and their cosmetologists and did not interfere with or prolong the client's salon visit. Women in the intervention group reported significantly higher rates of mammography compared to women in the control group. Training a single educator proved sufficient to permeate the entire salon with the health message, and salon clients agreed that cosmetologists could become effective health educators.

CONCLUSIONS

Cosmetologists are in an ideal position to increase African American women's breast cancer knowledge and adherence to breast cancer screening guidelines.

Interactions among genes, tumor biology and the environment in cancer health disparities: examining the evidence on a national and global scale

Cancer incidence and mortality rates show great variations across nations and between population groups. These variations are largely explained by differences in age distribution, diet and lifestyle, access to health care, cultural barriers and exposure to carcinogens and pathogens. Cancers caused by infections are significantly more common in developing than developed countries, and they overproportionally affect immigrant populations in the USA and other countries. The global pattern of cancer is not stagnant. Instead, it is dynamic because of fluctuations in the age distribution of populations, improvements in cancer prevention and early detection in affluent countries and rapid changes in diet and lifestyle in parts of the world. For example, increased smoking rates have caused tobacco-induced cancers to rise in various Asian countries, whereas reduced smoking rates have caused these cancers to plateau or even begin to decline in Western Europe and North America. Some population groups experience a disproportionally high cancer burden. In the USA and the Caribbean, cancer incidence and mortality rates are excessively high in populations of African ancestry when compared with other population groups. The causes of this disparity are multifaceted and may include tumor biological and genetic factors and their interaction with the environment. In this review, we will discuss the magnitude and causes of global cancer health disparities and will, with a focus on African-Americans and selected cancer sites, evaluate the evidence that genetic and tumor biological factors contribute to existing cancer incidence and outcome differences among population groups in the USA.

A study to investigate the role of p27 and cyclin E immunoexpression as a prognostic factor in early breast carcinoma

Background

Cyclin E and p27 expression is easy to assess in human tissues by standard immunohistochemical techniques. Immunohistochemistry is cost effective, relatively easy to perform and will play more of a role in the future management of cancer. The aim of this study was to investigate the role of p27 and cyclin E immunoexpression as a prognostic factor in early breast carcinoma.

Methods

Cyclin E and p27 immunohistochemistry was performed on sixty six cases of breast carcinoma submitted over a five year period to the Division of Anatomical Pathology, Groote Schuur hospital; Whittaker and Associates; and PathCare. All tumours included in this study were less than 5 cm in diameter (pT1 and pT2 stage) and all the patients had wide local excisions performed. Follow up information was obtained from patient folders in the Department of Radiation Oncology.

Results

There was no significant association of cyclin E and p27 expression with distant metastasis free survival (MFS) for all invasive carcinomas in contrast to grade, lymph node spread and vascular invasion. However, there was a statistically significant direct association of cyclin E with distant metastases in all invasive carcinomas, in the subgroup of infiltrating duct carcinomas (IDC) and in the node negative group when cyclin E was stratified as negative and positive (low/high). In this study of early breast carcinoma, only 9/66 cases showed cyclin E expression. Of these, four patients had distant metastases, one patient had a local recurrence and four patients were alive at last follow-up. Furthermore, cyclin E expression was significantly associated with grade, lymph node spread, oestrogen receptor status and histological type. None of the lobular carcinomas showed cyclin E positivity and only one case of lobular carcinoma presented with distant metastases.

59/66 cases were positive (low/high) for p27 while seven cases were negative, 22 cases showed low expression and 37 cases demonstrated high p27 expression.

p27 was significantly associated with oestrogen receptor status only for all invasive carcinomas and in the IDC group. There was no statistical relationship between p27 and cyclin E, but 50 (76%) tumours with positive p27 expression were negative for cyclin E. There were similar results for the invasive ductal carcinoma subgroup.

Conclusion

This study shows that p27 and cyclin E are not good independent prognostic markers for early breast carcinoma in contrast to grade, lymph node spread and vascular invasion for all invasive carcinomas. However, cyclin E provides some prognostic value as there is a direct statistical association with the development of distant metastases. Many previous studies have correlated overexpression of cyclin E with an aggressive course. The inverse relationship between p27 and cyclin E expression which has been reported in the literature has been highlighted, but this was not statistically significant. Most cases showed positive p27 expression and negative Cyclin E expression. This may be due to the early stage of the disease.

Triple-negative breast cancer in Hispanic patients: high prevalence, poor prognosis, and association with menopausal status, body mass index, and parity

BACKGROUND

Triple-negative breast cancer (TNBC) is defined as breast cancer that is negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. TNBC represents 15% of all invasive breast cancers, but some studies have suggested that its prevalence differs between races. To the authors' knowledge, no previous studies have determined the prevalence of TNBC and its risk factors among Hispanic women.

METHODS

The authors identified 2074 Hispanic women with breast cancer who attended the National Cancer Institute in Mexico City from 1998 to 2008. All histopathologic and immunohistochemical diagnoses were rereviewed by a breast cancer pathologist. The prevalence of TNBC, its association with clinicopathologic characteristics, and its prognostic impact were determined.

RESULTS

The median patient age at diagnosis (±standard deviation) was 50 ± 12 years. The overall prevalence of TNBC was 23.1%. Younger age (P < .001), premenopausal status (P = .002), increased parity (P = .029), hormonal contraceptive use (P = .04) high histologic grade (P < .001), and advanced disease (P < .001) were associated independently with TNBC. Postmenopausal patients who had a body mass index (BMI) <25 kg/m(2) (P = .027) or <30 kg/m(2) (P < .001) were more likely to have TNBC. In multivariate analysis, patients with TNBC had a higher risk of locoregional recurrence (LRR), lower disease-free survival (DFS) (hazard ratio, 1.62; 95% confidence interval, 1.13-2.32; P = .009), and a lower cancer-specific survival (CSS) rate (hazard ratio, 1.66; 95% confidence interval, 1.20-2.30; P = .002) than patients with non-TNBC.

CONCLUSIONS

The median age at diagnosis of Hispanic women with breast cancer was 11 years younger than the average age reported in the United States. The prevalence of TNBC in this study population was higher than that reported in white women with breast cancer. TNBC was associated with a higher risk of LRR and with lower DFS and CSS than those in patients with non-TNBC.

Outcomes in black patients with early breast cancer treated with breast conservation therapy

BACKGROUND

The race-specific impact of prognostic variables for early breast cancer is unknown for black patients undergoing breast conservation.

METHODS AND MATERIALS

This was a retrospective study of 1,231 consecutive patients ≥40 years of age with Stage I-II invasive breast cancer treated with lumpectomy and radiation therapy at the University of Chicago Hospitals and affiliates between 1986 and 2004. Patients were classified as either black or nonblack. Cox proportional hazards regression was used to model the effects of known prognostic factors and interactions with race.

RESULTS

Median follow-up for surviving patients was 82 months. Thirty-four percent of patients were black, and 66% were nonblack (Caucasian, Hispanic, and Asian). Black patients had a poorer 10-year overall survival (64.6% vs. 80.8%; adjusted hazard ratio [HR], 1.59; 95% confidence interval [CI], 1.23-2.06) and 10-year disease-free survival (58.1% vs. 75.4%; HR 1.49; 95% CI, 1.18-1.89) compared with nonblack patients. Tumor sizes were similar between nonblack and black patients with mammographically detected tumors (1.29 cm vs. 1.20 cm, p = 0.20, respectively). Tumor size was significantly associated with overall survival (HR 1.48; 95% CI, 1.12-1.96) in black patients with mammographically detected tumors but not in nonblack patients (HR 1.09; 95% CI, 0.78-1.53), suggesting that survival in black patients depends more strongly on tumor size in this subgroup. Tests for race-size method of detection interactions were statistically significant for overall survival (p = 0.049), locoregional control (p = 0.036), and distant control (p = 0.032) and borderline significant for disease-free survival (p = 0.067).

CONCLUSION

Despite detection at comparable sizes, the prognostic effect of tumor size in patients with mammographically detected tumors is greater for black than in nonblack patients.

Genome-wide copy number alterations in subtypes of invasive breast cancers in young white and African American women

Genomic copy number alterations (CNA) are common in breast cancer. Identifying characteristic CNAs associated with specific breast cancer subtypes is a critical step in defining potential mechanisms of disease initiation and progression. We used genome-wide array comparative genomic hybridization to identify distinctive CNAs in breast cancer subtypes from 259 young (diagnosed with breast cancer at <55 years) African American (AA) and Caucasian American (CA) women originally enrolled in a larger population-based study. We compared the average frequency of CNAs across the whole genome for each breast tumor subtype and found that estrogen receptor (ER)-negative tumors had a higher average frequency of genome-wide gain (P < 0.0001) and loss (P = 0.02) compared to ER-positive tumors. Triple-negative (TN) tumors had a higher average frequency of genome-wide gain (P < 0.0001) and loss (P = 0.003) than non-TN tumors. No significant difference in CNA frequency was observed between HER2-positive and -negative tumors. We also identified previously unreported recurrent CNAs (frequency >40%) for TN breast tumors at 10q, 11p, 11q, 16q, 20p, and 20q. In addition, we report CNAs that differ in frequency between TN breast tumors of AA and CA women. This is of particular relevance because TN breast cancer is associated with higher mortality and young AA women have higher rates of TN breast tumors compared to CA women. These data support the possibility that higher overall frequency of genomic alteration events as well as specific focal CNAs in TN breast tumors might contribute in part to the poor breast cancer prognosis for young AA women.

Age/race differences in HER2 testing and in incidence rates for breast cancer triple subtypes: a population-based study and first report

BACKGROUND

Although US year 2000 guidelines recommended characterizing breast cancers by human epidermal growth factor receptor 2 (HER2), national cancer registries do not collect HER2, rendering a population-based understanding of HER2 and clinical "triple subtypes" (estrogen receptor [ER] / progesterone receptor [PR] / HER2) largely unknown. We document the population-based prevalence of HER2 testing / status, triple subtypes and present the first report of subtype incidence rates.

METHODS

Medical records were searched for HER2 on 1842 metropolitan Atlanta females diagnosed with breast cancer during 2003-2004. HER2 testing/status and triple subtypes were analyzed by age, race/ethnicity, tumor factors, socioeconomic status, and treatment. Age-adjusted incidence rates were calculated.

RESULTS

Over 90% of cases received HER2 testing: 12.6% were positive, 71.7% negative, and 15.7% unknown. HER2 testing compliance was significantly better for women who were younger, of Caucasian or African-American descent, or diagnosed with early stage disease. Incidence rates (per 100,000) were 21.1 for HER2+ tumors and 27.8 for triple-negative tumors, the latter differing by race (36.3 and 19.4 for black and white women, respectively).

CONCLUSIONS

HER2 recommendations are not uniformly adhered to. Incidence rates for breast cancer triple subtypes differ by age/race. As biologic knowledge is translated into the clinical setting eg, HER2 as a biomarker, it will be incumbent upon national cancer registries to report this information. Incidence rates cautiously extrapolate to an annual burden of 3000 and 17,000 HER2+ tumors for black and white women, respectively, and triple-negative tumors among 5000 and 16,000 respectively. Testing, rate, and burden variations warrant population-based in-depth exploration and clinical translation.