Breast Cancer in Latinas: A Focus on Intrinsic Subtypes Distribution

Racial and socioeconomic disparities in triple-negative breast cancer treatment

INTRODUCTION

Triple-negative breast cancer (TNBC) continues to be a significant concern, especially among minority populations, where treatment disparities are notably pronounced. Addressing these disparities, especially among African American women and other minorities, is crucial for ensuring equitable healthcare.

AREAS COVERED

This review delves into the continuum of TNBC treatment, noting that the standard of care, previously restricted to chemotherapy, has now expanded due to emerging clinical trial results. With advances like PARP inhibitors, immunotherapy, and antibody-drug conjugates, a more personalized treatment approach is on the horizon. The review highlights innovative interventions tailored for minorities, such as utilizing technology like text messaging, smartphone apps, and targeted radio programming, coupled with church-based behavioral interventions.

EXPERT OPINION

Addressing TNBC treatment disparities demands a multifaceted approach, blending advanced medical treatments with culturally sensitive community outreach. The potential of technology, especially in the realm of promoting health awareness, is yet to be fully harnessed. As the field progresses, understanding and integrating the socio-economic, biological, and access-related challenges faced by minorities will be pivotal for achieving health equity in TNBC care.

Somatic Mutations in Latin American Breast Cancer Patients: A Systematic Review and Meta-Analysis

(1) Background: Somatic mutations may be connected to the exposome, potentially playing a role in breast cancer's development and clinical outcomes. There needs to be information regarding Latin American women specifically, as they are underrepresented in clinical trials and have limited access to somatic analysis in their countries. This study aims to systematically investigate somatic mutations in breast cancer patients from Latin America to gain a better understanding of tumor biology in the region. (2) Methods: We realize a systematic review of studies on breast cancer in 21 Latin American countries using various databases such as PubMed, Google Scholar, Web of Science, RedAlyc, Dianlet, and Biblioteca Virtual en Salud. Of 392 articles that fit the criteria, 10 studies have clinical data which can be used to create a database containing clinical and genetic information. We compared mutation frequencies across different breast cancer subtypes using statistical analyses and meta-analyses of proportions. Furthermore, we identified overexpressed biological processes and canonical pathways through functional enrichment analysis. (3) Results: 342 mutations were found in six Latin American countries, with the TP53 and PIK3CA genes being the most studied mutations. The most common PIK3CA mutation was H1047R. Functional analysis provided insights into tumor biology and potential therapies. (4) Conclusion: evaluating specific somatic mutations in the Latin American population is crucial for understanding tumor biology and determining appropriate treatment options. Combining targeted therapies may improve clinical outcomes in breast cancer. Moreover, implementing healthy lifestyle strategies in Latin America could enhance therapy effectiveness and clinical outcomes.

Real-world data on triple-negative breast cancer in Latin America and the Caribbean

Breast cancer (BC) is the most prevalent cancer in women in Latin America and the Caribbean. We compiled real-world data (RWD) on the epidemiology, diagnosis, treatment, and patient outcomes of triple-negative breast cancer (TNBC), addressing the main barriers to optimal care in Latin America. The prevalence of TNBC varies between 11% and 38.5% of all BC cases diagnosed in the region, and TNBC primarily affects young patients. Delays in BC diagnosis, with consequent advanced disease stages and barriers to access efficient therapies, particularly due to high costs, negatively impact patient outcomes. Cancer clinical trials are an opportunity to access standard and novel therapies for patients with this aggressive BC subtype and thus must be prioritised. Finally, generating RWD and cost-effectiveness studies in a region with limited resources is critical for decision-makers to define the incorporation of new technologies for the treatment of BC.

Discrepancies in breast cancer's oncological outcomes between public and private institutions in the southeast region of Brazil: a retrospective cohort study

Background

Brazil is a middle-income country with inequalities in its healthcare system. The disparities between public and private services affect the diagnosis and treatment of patients with breast cancer. The aim of this study is to assess whether disease-free survival (DFS) and overall survival (OS) are different in public and private specialized centers.

Patient and methods

A retrospective cohort study with 1,545 breast cancer patients diagnosed from 2003 to 2011 at Barretos Cancer Hospital-BCH (public group, N = 1,408) and InORP Oncoclinicas (private group, N = 137) was conducted. A 1:1 propensity score matching (PSM) analysis was used to adjust the differences between the groups' characteristics (n = 137 in each group).

Results

The median age at diagnosis was 54.4 years. Estimated DFS rates at 1, 5, and 10 years were 96.0%, 71.8%, and 59.6%, respectively, at BCH and 97.8%, 86.9%, and 78%, respectively, at InORP (HR: 2.09; 95% confidence interval [CI], 1.41-3.10; p < 0.0001). Estimated OS rates at 1, 5, and 10 years were 98.1%, 78.5%, and 65.4%, respectively, at BCH and 99.3%, 94.5%, and 91.9%, respectively, at InORP (HR: 3.84; 95% CI, 2.16-6.82; p < 0.0001). After adjustment by PSM, DFS and OS results in 1, 3, and 5 years remained worse in the public service compared to the private service.

Conclusion

Patients treated in a public center have worse DFS and OS after a follow-up period of more than 5 years. These results were corroborated after carrying out the PSM.

Medicaid expansion, chemotherapy delays, and racial disparities among women with early-stage breast cancer

BACKGROUND

Medicaid expansion under the Affordable Care Act extends eligibility for participating states and has been associated with improved outcomes by facilitating access to care. Delayed initiation of adjuvant chemotherapy is associated with worse outcomes among patients with early-stage breast cancer (BC). The impact of Medicaid expansion in narrowing delays by race and ethnicity has not been studied, to our knowledge.

METHODS

This was a population-based study using the National Cancer Database. Patients diagnosed with primary early-stage BC between 2007 and 2017 residing in states that underwent Medicaid expansion in January 2014 were included. Time to chemotherapy initiation and proportion of patients experiencing chemotherapy delays (>60 days) were evaluated using difference-in-difference and Cox proportional hazards models in preexpansion and postexpansion periods according to race and ethnicity.

RESULTS

A total 100 643 patients were included (63 313 preexpansion and 37 330 postexpansion). After Medicaid expansion, the proportion of patients experiencing chemotherapy initiation delay decreased from 23.4% to 19.4%. The absolute decrease was 3.2, 5.3, 6.4, and 4.8 percentage points (ppt) for Black, Hispanic, White, and Other patients. Compared with White patients, statistically significant adjusted difference-in-differences were observed for Black (-2.1 ppt, 95% confidence interval [CI] = -3.7% to -0.5%) and Hispanic patients (-3.2 ppt, 95% CI = -5.6% to -0.9%). Statistically significant reductions in time to chemotherapy between expansion periods were observed among White patients (adjusted hazard ratio = .11, 95% CI = 1.09 to 1.12) and those belonging to racialized groups (adjusted hazard ratio  = 1.14, 95% CI = 1.11 to 1.17).

CONCLUSIONS

Among patients with early-stage BC, Medicaid expansion was associated with a reduction in racial disparities by decreasing the gap in the proportion of Black and Hispanic patients experiencing delays in adjuvant chemotherapy initiation.

Association of genetic ancestry with HER2, GRB7 AND estrogen receptor expression among Colombian women with breast cancer

Background

Our previous study reported higher mRNA levels of the human epidermal growth factor receptor 2 (HER2)-amplicon genes ERBB2 and GRB7 in estrogen receptor (ER)-positive breast cancer patients with relatively high Indigenous American (IA) ancestry from Colombia. Even though the protein expression of HER2 and GRB7 is highly correlated, they may also express independently, an event that could change the patients' prognosis. In this study, we aimed to explore the differences in ER, HER2 and GRB7 protein expression according to genetic ancestry, to further assess the clinical implications of this association.

Methods

We estimated genetic ancestry from non-tumoral breast tissue DNA and assessed tumoral protein expression of ER, HER2, and GRB7 by immunohistochemistry in a cohort of Colombian patients from different health institutions. We used binomial and multinomial logistic regression models to test the association between genetic ancestry and protein expression. Kaplan-Meier and log-rank tests were used to evaluate the effect of HER2/GRB7 co-expression on patients' survival.

Results

Our results show that patients with higher IA ancestry have higher odds of having HER2+/GRB7- breast tumors, compared to the HER2-/GRB7- subtype, and this association seems to be stronger among ER-positive tumors (ER+/HER2+/GRB7-: OR=3.04, 95% CI, 1.47-6.37, p<0.05). However, in the multivariate model this association was attenuated (OR=1.80, 95% CI, 0.72-4.44, p=0.19). On the other hand, it was observed that having a higher European ancestry patients presented lower odds of ER+/HER2+/GRB7- breast tumors, this association remained significant in the multivariate model (OR=0.36, 95% CI, 0.13 - 0.93, p= 0.0395). The survival analysis according to HER2/GRB7 co-expression did not show statistically significant differences in the overall survival and recurrence-free survival.

Conclusions

Our results suggest that Colombian patients with higher IA ancestry and a lower European fraction have higher odds of ER+/HER2+/GRB7- tumors compared to ER+/HER2-/GRB7- disease. However, this association does not seem to be associated with patients' overall or recurrence-free survival.

Chemokine receptors differentially expressed by race category and molecular subtype in the breast cancer TCGA cohort

Racial disparities in mortality due to metastasis remain significant among breast cancer patients. Chemokine receptors contribute to breast tumors and metastatic outcome. We explored for significant differences in chemokine receptor expression in breast tumors from Black, Asian, and White patients in The Cancer Genome Atlas. We show that despite sharing the same molecular subtype, expression of the chemokine receptors ACKR1, CCR3, CCR6, CCRL1, CCRL2, CXCR1, CXCR2, CXCR4, CXCR6, and CXC3CR1 was significantly different depending on racial group. For patients with triple negative breast cancer, CCR3 was higher in Black versus White and CCRL2 was higher in Asian versus White. In luminal A tumors, ACKR1 was lower in Asian versus White, CCR3 was higher in Black versus White, and CCR6 and CXC3CR1 were lower in Black versus White. In luminal B tumors, CCRL2 was lower in Black versus White, CXCR1 and CXC3CR1 were lower in Asian versus White, and CXCR2 was lower in Black and Asian versus White. In HER2 enriched tumors, CCR3 was higher in Black versus White and CXCR4 lower in Asian versus White. CCR3, CCR6, and CXCR6 associated with worse patient survival. These findings can inform improved treatment strategies to decrease racial disparities in breast cancer burden.

Cancer Epidemiology in Hispanic Populations: What Have We Learned and Where Do We Need to Make Progress?

The Hispanic/Latino(x) population (H/L) in the United States of America is heterogeneous and fast growing. Cancer is the number one cause of death among H/Ls, accounting for 21% of deaths. Whereas for the most common cancers, incidence rates are lower in H/Ls compared with non-H/L White (NHW) individuals, H/Ls have a higher incidence of liver, stomach, cervical, penile, and gallbladder cancers. H/L patients tend to be diagnosed at more advanced stages for breast, colorectal, prostate, and lung cancers, and melanoma compared with NHW individuals. Etiologic and cancer outcomes research among H/Ls lags other populations. In this review, we provide a summary of challenges, opportunities, and research priorities related to cancer etiology, cancer outcomes, and survivorship to make progress in addressing scientific gaps. Briefly, we prioritize the need for more research on determinants of obesity, nonalcoholic fatty liver disease and its progression to liver cancer, stomach and gallbladder cancers, and pediatric acute lymphoblastic leukemia. We emphasize the need to improve cancer screening, early detection of cancer, and survivorship care. We highlight critical resources needed to make progress in cancer epidemiologic studies among H/L populations, including the importance of training the next generation of cancer epidemiologists conducting research in H/Ls.

The Transcriptomic Portrait of Locally Advanced Breast Cancer and Its Prognostic Value in a Multi-Country Cohort of Latin American Patients

Purposes

Most molecular-based published studies on breast cancer do not adequately represent the unique and diverse genetic admixture of the Latin American population. Searching for similarities and differences in molecular pathways associated with these tumors and evaluating its impact on prognosis may help to select better therapeutic approaches.

Patients and Methods

We collected clinical, pathological, and transcriptomic data of a multi-country Latin American cohort of 1,071 stage II-III breast cancer patients of the Molecular Profile of Breast Cancer Study (MPBCS) cohort. The 5-year prognostic ability of intrinsic (transcriptomic-based) PAM50 and immunohistochemical classifications, both at the cancer-specific (OSC) and disease-free survival (DFS) stages, was compared. Pathway analyses (GSEA, GSVA and MetaCore) were performed to explore differences among intrinsic subtypes.

Results

PAM50 classification of the MPBCS cohort defined 42·6% of tumors as LumA, 21·3% as LumB, 13·3% as HER2E and 16·6% as Basal. Both OSC and DFS for LumA tumors were significantly better than for other subtypes, while Basal tumors had the worst prognosis. While the prognostic power of traditional subtypes calculated with hormone receptors (HR), HER2 and Ki67 determinations showed an acceptable performance, PAM50-derived risk of recurrence best discriminated low, intermediate and high-risk groups. Transcriptomic pathway analysis showed high proliferation (i.e. cell cycle control and DNA damage repair) associated with LumB, HER2E and Basal tumors, and a strong dependency on the estrogen pathway for LumA. Terms related to both innate and adaptive immune responses were seen predominantly upregulated in Basal tumors, and, to a lesser extent, in HER2E, with respect to LumA and B tumors.

Conclusions

This is the first study that assesses molecular features at the transcriptomic level in a multicountry Latin American breast cancer patient cohort. Hormone-related and proliferation pathways that predominate in PAM50 and other breast cancer molecular classifications are also the main tumor-driving mechanisms in this cohort and have prognostic power. The immune-related features seen in the most aggressive subtypes may pave the way for therapeutic approaches not yet disseminated in Latin America.

Clinical Trial Registration

ClinicalTrials.gov (Identifier: NCT02326857).

Androgen receptor expression and prognosis in Hispanic/Latino women with triple negative breast cancer

INTRODUCTION AND OBJECTIVE

Triple-negative breast cancer (TNBC) is an aggressive subtype that has no available molecular targets. It occurs most often in premenopausal African-American and Hispanic/Latino women. In Colombia, its prevalence has been reported to be 20.6%. Androgen receptor (AR) belongs to the steroid nuclear receptor family and has been recently considered a potential biomarker for breast cancer. Considering the high prevalence of TNBC in Colombian women and the lack of knowledge of AR expression, our aim was to determine the frequency of AR expression and its association with pathological variables.

MATERIALS AND METHODS

149 women diagnosed with TNBC between 2011 and 2014 were included. Clinical and pathological data were obtained from medical and pathology reports. Information on hormone receptor status, Ki67 expression and HER2 was reevaluated by a pathologist. AR expression was considered positive when it exceeded 1% of nuclear staining in tumor cells.

RESULTS

AR expression was detected in 41.6% of the samples. Although we did not find statistically significant differences in clinic-pathological variables according to AR expression, patients with AR expression over 50% were younger (53.92 years vs. 60.78 years, p=0.027) and presented higher Ki67 expression (64.06% vs. 47.32%, p=0.05), compared to patients with a low AR expression. The median overall survival in our sample of TNBC patients was 2.45 years.

CONCLUSIONS

The expression of AR in our sample was similar to the expression in populations of European descent. We found statistically significant differences in age at diagnosis and Ki67 expression according to AR expression.

The impact of race and ethnicity in breast cancer-disparities and implications for precision oncology

Breast cancer is the most commonly diagnosed cancer worldwide and is one of the leading causes of cancer death. The incidence, pathological features, and clinical outcomes in breast cancer differ by geographical distribution and across racial and ethnic populations. Importantly, racial and ethnic diversity in breast cancer clinical trials is lacking, with both Blacks and Hispanics underrepresented. In this forum article, breast cancer researchers from across the globe discuss the factors contributing to racial and ethnic breast cancer disparities and highlight specific implications of precision oncology approaches for equitable provision of breast cancer care to improve outcomes and address disparities.

Breast cancer screening outcomes among Mexican-origin Hispanic women participating in a breast cancer screening program

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We observed a higher recall rate for diagnostic testing in this population.

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Breast density distribution was different to both Hispanic and other populations.

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We did not observe lower biopsy rates compared to other populations.

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Age, health status, and years in the US were associated with breast density.

Breast cancer is the commonest occurring cancer and the leading cause of cancer death among Hispanic women in the USA. Although their overall breast cancer incidence and mortality is lower, incidence rates are rising faster and mortality declines are lower than other groups. It is expected that the breast cancer burden will rise as this population ages and becomes more acculturated. It is therefore important to better characterize their screening outcomes. This is an observational study of socioeconomically disadvantaged Hispanic women participating in a community-based breast cancer screening program that offered no-cost testing and navigation services in two US-Mexico border counties. Outcomes include results of screening mammograms, diagnostic tests and breast findings. Of 1,966 eligible women, 1,675 (85%) completed a screening mammogram and were included in this analysis. Mean age was 56 years (SD: 6.8 years, range 50 to 75.6 years); 99% were Hispanic and 83.6% had less than high school education. 19.3% of the initial mammogram results were abnormal (BIRADS 0, 3, 4, or 5); a diagnostic mammogram was indicated in 12.2% (n = 205), a diagnostic ultrasound in 26.4% (n = 443), and biopsies in 3.0% (n = 51) of the total. Eleven women (0.66%) had breast cancer diagnosed. Mexican-origin Hispanic women had higher recall rates, but similar biopsy and cancer rates to general screening populations despite their overall lower incidence and mortality in the USA. This suggests that the expected rise in future breast cancer burden among US Hispanics due to aging and acculturation could occur sooner than expected.

"I never heard anything about it": Knowledge and psychosocial needs of Latina breast cancer survivors with lymphedema

Objective:

Breast cancer is the most commonly diagnosed form of cancer and the leading cause of cancer-related death among Latina women in the United States. One aspect of recovery that has been underrepresented in the English-language literature is the recovery of Latina women who have developed lymphedema, a debilitating condition characterized by persistent swelling of the arm, hand, chest, and/or breast. To fill this research gap, a study was conducted to examine the lived experiences of Latina women with breast cancer-related lymphedema.

Methods:

Given the limited scholarship on this topic, qualitative methods were used to obtain a foundational and nuanced understanding of Latina women’s experiences. Semi-structured interviews were conducted with a sample of 10 Latina survivors with breast cancer-related lymphedema. Data were analyzed through thematic analysis and constant comparison methodology.

Results:

The data analysis yielded three major themes: knowledge of lymphedema, impact of lymphedema diagnosis, and coping with lymphedema. Participants had limited knowledge of lymphedema and its risk factors upon diagnosis, in addition to barriers accessing quality care. They also noted psychological distress related to a significant financial burden as well as social anxiety related to interacting with others while wearing compression gloves or sleeves. A major coping strategy was receiving social support from friends, family, peers in structured support groups, and spiritual/religious groups or practices.

Conclusions:

Our findings bring to light contextual factors that may place Latina breast cancer survivors at increased risk for lymphedema and for experiencing a high burden managing their condition. Recommendations are provided for primary, secondary, and tertiary prevention.

Creating community: Expanding access to psychosocial programs for Latina breast cancer survivors

OBJECTIVE

Breast cancer survivors often derive benefits from psychosocial interventions, but less is known about Latina women's experiences. Given the disproportionately high disease burden faced by Latina survivors, it is critical to examine ways to enhance access for this population. Thus, the present study aimed to (a) examine women's perceptions of factors associated with effective delivery of a psychosocial program designed for Spanish speaking women with limited access to care, and (b) identify the mechanisms by which the program enhanced women's psychological well-being.

METHODS

In a qualitative study, in-depth interviews were conducted with 15 immigrant Latina breast cancer survivors who previously received psychosocial services at a community-based organization. Grounded theory was used to analyze the data.

RESULTS

Through open, axial, and selective coding, we arrived at the core category achieving a sense of community. The psychosocial program promoted access and enhanced women's psychological well-being by creating a sense of community among participants. This was facilitated by three primary aspects of service provision: access factors, a holistic approach to health, and therapeutic factors imparted through a biweekly support group.

CONCLUSIONS

Psychosocial services promoted a sense of community among Latina breast cancer survivors while reflecting their cultural values and unique psychosocial needs. Findings may guide the development of interventions to increase access to care, enhance health outcomes, and create and maintain a sense of community among medically underserved populations.

Knowledge of the Relationship Between Breastfeeding and Breast Cancer Risk Among Racial and Ethnic Minority Women

Research indicates breastfeeding can reduce the risk of breast cancer in women. Black and Hispanic women are more likely to die from breast cancer than non-Hispanic white women and are least likely to breastfeed. The current study was designed to evaluate women's knowledge of the link between breastfeeding and decreased breast cancer risk among a racially diverse cohort of pregnant women. Pregnant women 18 and older (N = 89; 48.4% black; 28% Hispanic) were recruited during a prenatal visit to complete a survey. Women indicated limited understanding of the association between breastfeeding and breast cancer risk reduction; less than 40% of black and white women indicated knowledge, while 64.7% of Hispanic women were aware of the association. These findings underscore the need for interventions to educate women about the protective benefits of breastfeeding as a strategy to reduce their breast cancer incidence and mortality.

Association between tumor mutation profile and clinical outcomes among Hispanic Latina women with triple-negative breast cancer

Triple-negative breast cancer (TNBC) represents 15%-20% of all breast cancer types. It is more common among African American (AA) and Hispanic-Latina (HL) women. The biology of TNBC in HL women has been poorly characterized, but some data suggest that the molecular drivers of breast cancer might differ. There are no clinical tools to aid medical oncologists with decisions regarding appropriate individualized therapy, and no way to predict long-term outcomes. The aim of this study was to characterize individual patient gene mutation profiles and to identify the relationship with clinical outcomes. We collected formalin-fixed paraffin-embedded tumors (FFPE) from women with TNBC. We analyzed the gene mutation profiles of the collected tumors and compared the results with individual patient's clinical histories and outcomes. Of 25 patients with TNBC, 24 (96%) identified as HL. Twenty-one (84%) had stage III-IV disease. The most commonly mutated genes were TP53, NOTCH1, NOTCH2, NOTCH3, AKT, MEP3K, PIK3CA, and EGFR. Compared with other international cancer databases, our study demonstrated statistically significant higher frequencies of these genes among HL women. Additionally, a worse clinical course was observed among patients whose tumors had mutations in NOTCH genes and PIK3CA. This study is the first to identify the most common genetic alterations among HL women with TNBC. Our data strongly support the notion that molecular drivers of breast cancer could differ in HL women compared with other ethnic backgrounds. Therefore, a deeper understanding of the biological mechanisms behind NOTCH gene and PIK3CA mutations may lead to a new treatment approach.

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.

Breast Cancer Health Disparities in Hispanics/Latinas

Purpose of the review

Breast cancer incidence and mortality rates are lower in some Hispanic/Latino subpopulations compared to Non-Hispanic White women. However, studies suggest that the risk of breast cancer-specific mortality is higher in US Hispanics/Latinas. In this review we summarized current knowledge on factors associated with breast cancer incidence and risk of mortality in women of Hispanic/Latino origin.

Recent findings

Associative studies have proposed a multiplicity of factors likely contributing to differences in breast cancer incidence and survival between population groups, including socioeconomic/sociodemographic factors, lifestyle choices as well as access to and quality of care. Reports of association between global genetic ancestry overall as well as subtype-specific breast cancer risk among Hispanic/Latinas suggest that incidence and subtype distribution could result from differential exposure to environmental and lifestyle related factors correlated with genetic ancestry as well as germline genetic variation.

Summary

Hispanic/Latino in the United States have been largely underrepresented in cancer research. It is important to implement inclusive programs that facilitate the access of this population to health services and that also include education programs for the community on the importance of screening. In addition, it is important to continue promoting the inclusion of Hispanics/Latinos in genomic studies that allow understanding the biological behavior of this disease in the context of all human genetic diversity.

Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer Is Associated with Indigenous American Ancestry in Latin American Women

Women of Latin American origin in the United States are more likely to be diagnosed with advanced breast cancer and have a higher risk of mortality than non-Hispanic White women. Studies in U.S. Latinas and Latin American women have reported a high incidence of HER2 positive (+) tumors; however, the factors contributing to this observation are unknown. Genome-wide genotype data for 1,312 patients from the Peruvian Genetics and Genomics of Breast Cancer Study (PEGEN-BC) were used to estimate genetic ancestry. We tested the association between HER2 status and genetic ancestry using logistic and multinomial logistic regression models. Findings were replicated in 616 samples from Mexico and Colombia. Average Indigenous American (IA) ancestry differed by subtype. In multivariate models, the odds of having an HER2+ tumor increased by a factor of 1.20 with every 10% increase in IA ancestry proportion (95% CI, 1.07-1.35; P = 0.001). The association between HER2 status and IA ancestry was independently replicated in samples from Mexico and Colombia. Results suggest that the high prevalence of HER2+ tumors in Latinas could be due in part to the presence of population-specific genetic variant(s) affecting HER2 expression in breast cancer. SIGNIFICANCE: The positive association between Indigenous American genetic ancestry and HER2+ breast cancer suggests that the high incidence of HER2+ subtypes in Latinas might be due to population and subtype-specific genetic risk variants.

Efficacy of Neoadjuvant Versus Adjuvant Chemotherapy in Hispanic/Latino (H/L) Women With Local or Locally Advanced Triple-negative Breast Cancer (TNBC)

BACKGROUND/AIM

The aim of the study was to investigate the efficacy of neoadjuvant and chemotherapy (NACT) and adjuvant chemotherapy (ACT) in Hispanic/Latino (H/L) women with TNBC.

PATIENTS AND METHODS

We reviewed the charts of patients with TNBC, stages I-III, treated at TTUHSC from 2006 to 2016. Overall survival (OS) and recurrence-free survival (RFS) were estimated and compared between the treatment groups. Kaplan-Meier curve and Cox proportional hazards regression analyses were conducted to estimate unadjusted and adjusted effects of NACT compared to ACT.

RESULTS

A total of 104 patients with TNBC, 30 (29%) received NACT and 74 (71%) ACT. Women undergoing NACT were younger, with a mean age of 50.8 years. Of the 30 patients who received NACT, 12 (40%) had pathologically complete response (pCR). Women who achieved pCR had an excellent RFS (HR=0.5, p=0.001). Women with residual cancer after NACT had worse outcome compared to patients who received ACT (HR=1.7, p=0.005).

CONCLUSION

pCR to NACT is a powerful surrogate for OS in H/L women with TNBC.

Integrated copy number and miRNA expression analysis in triple negative breast cancer of Latin American patients

Triple negative breast cancer (TNBC), a clinically aggressive breast cancer subtype, affects 15–35% of women from Latin America. Using an approach of direct integration of copy number and global miRNA profiling data, performed simultaneously in the same tumor specimens, we identified a panel of 17 miRNAs specifically associated with TNBC of ancestrally characterized patients from Latin America, Brazil. This panel was differentially expressed between the TNBC and non-TNBC subtypes studied (p ≤ 0.05, FDR ≤ 0.25), with their expression levels concordant with the patterns of copy number alterations (CNAs), present mostly frequent at 8q21.3-q24.3, 3q24-29, 6p25.3-p12.2, 1q21.1-q44, 5q11.1-q22.1, 11p13-p11.2, 13q12.11-q14.3, 17q24.2-q25.3 and Xp22.33-p11.21. The combined 17 miRNAs presented a high power (AUC = 0.953 (0.78–0.99);95% CI) in discriminating between the TNBC and non-TNBC subtypes of the patients studied. In addition, the expression of 14 and 15 of the 17miRNAs was significantly associated with tumor subtype when adjusted for tumor stage and grade, respectively. In conclusion, the panel of miRNAs identified demonstrated the impact of CNAs in miRNA expression levels and identified miRNA target genes potentially affected by both CNAs and miRNA deregulation. These targets, involved in critical signaling pathways and biological functions associated specifically with the TNBC transcriptome of Latina patients, can provide biological insights into the observed differences in the TNBC clinical outcome among racial/ethnic groups, taking into consideration their genetic ancestry.

Breast cancer subtype and survival among Indigenous American women in Peru

Latina women in the U.S. have relatively low breast cancer incidence compared to Non-Latina White (NLW) or African American women but are more likely to be diagnosed with the more aggressive “triple negative” breast cancer (TNBC). Latinos in the U.S. are a heterogeneous group originating from different countries with different cultural and ancestral backgrounds. Little is known about the distribution of tumor subtypes in Latin American regions. Clinical records of 303 female Peruvian patients, from the Peruvian National Cancer Institute, were analyzed. Participants were diagnosed with invasive breast cancer between 2010 and 2015 and were identified as residing in either the Selva or Sierra region. We used Fisher’s exact test for proportions and multivariable Cox Proportional Hazards Models to compare overall survival between regions. Women from the Selva region were more likely to be diagnosed with TNBC than women from the Sierra region (31% vs. 14%, p = 0.01). In the unadjusted Cox model, the hazard of mortality was 1.7 times higher in women from the Selva than the Sierra (p = 0.025); this survival difference appeared to be largely explained by differences in the prevalence of TNBC. Our results suggest that the distribution of breast cancer subtypes differs between highly Indigenous American women from two regions of Peru. Disentangling the factors that contribute to this difference will add valuable information to better target prevention and treatment efforts in Peru and improve our understanding of TNBC among all women. This study demonstrates the need for larger datasets of Latin American patients to address differences between Latino subpopulations and optimize targeted prevention and treatment.