Population differences in breast cancer: survey in indigenous African women reveals over-representation of triple-negative breast cancer

Female breast cancer classification using immunohistochemistry biomarkers staining in Botswana

Breast cancer remains the most diagnosed cancer among women world-wide and a leading cause of cancer-related deaths accounting for 15% of deaths in 2018. Worldwide, the incidence increased from 1.4 million in 2011 to over 2 million in 2018 with a concomitant increase in mortality from 458,400 to 626,679 in the same period. Low- and middle-income countries, such as Botswana, have a disproportionate burden of breast cancer incidence and mortality and there is an urgent need to characterise the unique tumour molecular profiles that may be influencing mortality in these populations. Methods A retrospective study of 125 archived mastectomy specimens (from 2006 to 2009) from women with breast cancer in Botswana was conducted. We determined molecular characteristics of breast cancers by carrying out four immunohistochemistry (IHC)classification (PR, ER, HER2 receptors and Ki 67), cytokeratin 5/6 and EGFR1.Statistical software STATA and SPSS were used to determine the relationship between histology, IHC of biomarkers of interest. Results Out of 125 breast cancer tissues, the distribution of molecular subtypes were as follows: Luminal A (44/125; 35.2%), Luminal B (and TNBC (23/125; 18,4%), HER2 Enriched (17/125; 13.6%), and Luminal B HER2 Enriched (9/125; 7.2%), Basal (9/125; 7.2%), and CK5/6 was expressed by 12.8% (16/125) of tumours. Furthermore 6% of the tumours were basal positive luminal tumours. Morphological 76% of tumours were IDC-NOS and 24% were special type, majority were grade 2 (40%) followed by grade 1(30.4%), grade 3 (23.2%) was and mucinous types were 6.4%. Clinical staging and tumour involvement data were incomplete. Conclusion The discovery of basal positive luminal breast tumours in women from Botswana original not accounted for in the four distinct molecular subtype calls for an expanded antibody panel 6-IHC panel) in order to stratify women of African descent patients into good/poor prognostic groups. Characterising tumour subtypes will better inform optimal therapeutic regimens for women with breast cancer in Botswana.

Creation and Characterization of a Breast Cancer Tissue Microarray Including Black and White Patients from Florida and Hispanic Patients from Puerto Rico and Florida

Breast cancer is a leading cause of cancer-related mortality among women worldwide and is known to have higher mortality among women with African ancestry. Herein, we describe the creation and characterization of a multiethnic breast cancer tissue microarray (ME-BrTMA) representing tumors from non-Hispanic White (n = 41), non-Hispanic Black (NHB; n = 45), and Hispanic patients from Puerto Rico (n = 36) and Florida (n = 52). This ME-BrTMA comprises five blocks with a total of 610 cores: 371 breast cancer tumor cores, 93 breast stromal cores, 96 normal breast tissue cores, 30 non-breast cancer tumor cores, and 20 cores representing normal tissues. Initial characterization of the ME-BrTMA includes standard IHC staining of well-characterized clinical biomarkers, including the estrogen hormone receptors and progesterone hormone receptors, HER2, and Ki-67, interpreted by the coauthoring pathologist (Marilin Rosa). The IHC results indicated good but imperfect alignment with clinical diagnoses. Cores from breast cancer tumors from the NHB cohort most frequently scored negative for estrogen receptor (63%, P < 0.005) and progesterone receptor (80%, P < 0.005) and most frequently have high expression of the Ki-67 proliferation marker (38%, P < 0.05). Prediction Analysis of Microarray 50 (PAM50) analysis using RNA from secondary patient blocks showed that the NHB group also most frequently scored in the basal-like category (61%, P < 0.05). Taken together, the initial characterization of the ME-BrTMA suggests that it may serve as a representative resource to understand the underlying biology of breast cancer and its relationship to patient outcomes.

SIGNIFICANCE

The ME-BrTMA described herein provides a resource that may serve as a tool to understand the underlying biology of breast cancer.

Exploration of Traditional Chinese Medicine Comprehensive Treatment of Triple Negative Breast Cancer Based on Molecular Pathological Mechanism

Triple-negative breast cancer (TNBC) is recognized as the most aggressive subtype of breast cancer and is associated with poor prognosis. Clinically, TNBC is associated with significant invasiveness, high propensity for metastasis, frequent recurrence, and unfavorable outcomes. The absence of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2) in TNBC renders it unresponsive to endocrine therapies and treatments that target HER2. Consequently, the current therapeutic options are primarily confined to surgical intervention, adjuvant chemotherapy, and radiotherapy. Given the considerable heterogeneity of TNBC, targeted therapies have emerged as promising avenues for treatment. Furthermore, immunotherapy has demonstrated the potential to enhance overall survival and therapeutic response in patients with TNBC. Additionally, research indicates that traditional Chinese medicine (TCM) may yield beneficial effects in the management of this cancer subtype. This review aims to consolidate recent advancements in treatment strategies for TNBC, particularly those based on molecular subtypes.

Understanding Susceptibility to Breast Cancer: From Risk Factors to Prevention Strategies

Breast cancer is the most common malignancy among women globally, with incidence rates continuing to rise. A comprehensive understanding of its risk factors and the underlying biological mechanisms that drive tumor initiation is essential for developing effective prevention strategies. This review examines key non-modifiable risk factors, such as genetic predisposition, demographic characteristics, family history, mammographic density, and reproductive milestones, as well as modifiable risk factors like exogenous hormone exposure, obesity, diet, and physical inactivity. Importantly, reproductive history plays a dual role, providing long-term protection while temporarily increasing breast cancer risk shortly after pregnancy. Current chemoprevention strategies primarily depend on selective estrogen receptor modulators (SERMs), including tamoxifen and raloxifene, which have demonstrated efficacy in reducing the incidence of estrogen receptor-positive breast cancer but remain underutilized due to adverse effects. Emerging approaches such as aromatase inhibitors, RANKL inhibitors, progesterone antagonists, PI3K inhibitors, and immunoprevention strategies show promise for expanding preventive options. Understanding the interactions between risk factors, hormonal influences, and tumorigenesis is critical for optimizing breast cancer prevention and advancing safer, more targeted chemopreventive interventions.

Coding and regulatory somatic profiling of triple-negative breast cancer in Sub-Saharan African patients

The burden of triple-negative breast cancer (TNBC) may be shaped by genetic factors, particularly inherited and somatic mutation profiles. However, data on this topic remain limited, especially for the African continent, where a higher TNBC incidence is observed. In the age of precision medicine, cataloguing TNBC diversity in African patients becomes imperative. We performed whole exome sequencing, including untranslated regions, on 30 samples from Angola and Cape Verde, which allowed to ascertain on potential regulatory mutations in TNBC for the first time. A high somatic burden was observed for the African cohort, with 86% of variants being so far unreported. Recurring to predictive functional algorithms, 17% of the somatic single nucleotide variants were predicted to be deleterious at the protein level, and 20% overlapped with candidate cis-regulatory elements controlling gene expression. Several of these somatic functionally-impactful mutations and copy number variation (mainly in 1q, 8q, 6 and 10p) occur in known BC- and all cancer-driver genes, enriched for several cancer mechanisms, including response to radiation and related DNA repair mechanisms. TP53 is the top of these known BC-driver genes, but our results identified possible novel TNBC driver genes that may play a main role in the African context, as TTN, CEACAM7, DEFB132, COPZ2 and GAS1. These findings emphasize the need to expand cancer omics screenings across the African continent, the region of the globe with highest genomic diversity, accelerating the discovery of new somatic mutations and cancer-related pathways.

West African Genetic Ancestry and Breast Cancer Outcomes Among Black Women

Importance

Young Black women bear a disproportionate burden of breast cancer deaths compared with White women, yet they remain underrepresented in genomic studies.

Objective

To evaluate the association of biological factors, including West African genetic ancestry, and nonbiological factors with disease-free survival (DFS) among young Black women with breast cancer.

Design, Setting, and Participants

This observational cohort study included Black women diagnosed with invasive breast cancer between January 1, 2005, and December 31, 2016. Participants diagnosed with breast cancer at age 50 years or younger were recruited through the Florida and Tennessee state cancer registries. The final analysis was completed between June and September 2024.

Exposure

West African genetic ancestry.

Main Outcomes and Measures

A multivariable model was developed to evaluate the association between West African genetic ancestry and breast cancer DFS, adjusting for immunohistochemistry subtype, lymph node (LN) status, and full-time employment.

Results

This study included 687 Black women with early-stage invasive breast cancer. Their median age at diagnosis was 44 years (IQR, 38-47 years), and the median follow-up was 10 years (IQR, 7-11 years). In multivariable analysis, triple-negative breast cancer (TNBC) and LN involvement were associated with shorter breast cancer DFS (hazard ratio, 1.81 [95% CI, 1.20-2.73] and 1.77 [95% CI, 1.30-2.41], respectively), whereas full-time employment was associated with improved outcomes (hazard ratio, 0.44 [95% CI, 0.30-0.63]). Among the 551 participants for whom global genetic ancestry could be assessed, having a higher percentage of West African genetic ancestry was associated with shorter breast cancer DFS among 246 participants in the hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (ERBB2 [formerly HER2])-negative subgroup (hazard ratio, 1.45 [95% CI, 1.04-2.04]). Of the 369 participants (53.7%) with PAM50 data available, basal (133 [36.0%]) and luminal B (107 [29.0%]) subtypes were the most common. Among the 179 patients with HR-positive/ERBB2-negative disease and PAM50 data available, luminal B and basal subtypes combined were also overrepresented (81 [45.3%] and 24 [13.4%], respectively) compared with luminal A (70 [39.1%]).

Conclusions and Relevance

In this study of young Black women with breast cancer, having a higher percentage of West African genetic ancestry, TNBC, and LN involvement were associated with shorter breast cancer DFS. Interestingly, full-time employment was associated with improved breast cancer DFS. These findings highlight the importance of considering genetic ancestry beyond self-reported race and accounting for social determinants of health, in efforts to improve survival outcomes among Black women with breast cancer.

Worse Clinical and Survival Outcomes in Breast Cancer Patients Living in Puerto Rico Compared to Hispanics, Non-Hispanic Blacks, and Non-Hispanic Whites from Florida

BACKGROUND

Herein, we report the characterization of four cohorts of breast cancer patients including (1) non-Hispanic Whites in Florida, (2) non-Hispanic Blacks in Florida, (3) Hispanics in Florida, and (4) Hispanics in Puerto Rico.

METHODS

Data from female breast cancer patients were collected from cancer registry (n = 9361) and self-reported patient questionnaires (n = 4324). Several statistical tests were applied to identify significant group differences.

RESULTS

Breast cancer patients from Puerto Rico were least frequently employed and had the lowest rates of college education among the groups. They also reported more live births and less breastfeeding. Both Hispanic groups reported a higher fraction experiencing menstruation at age 11 or younger (Floridian Hispanics [38%] and Puerto Ricans [36%]) compared to non-Hispanic Whites (20%) and non-Hispanic Blacks (22%). Non-Hispanic Black and Puerto Rican women were significantly older at breast cancer diagnosis than their non-Hispanic White and Floridian Hispanic counterparts. The Puerto Rican and non-Hispanic Black groups more frequently had pathology stage T2 or higher primary breast tumors at diagnosis (non-Hispanic Whites [29%], non-Hispanic Blacks [39%], Floridian Hispanics [33%], Puerto Ricans [46%]). The Puerto Rican (73%, 95% CI [66, 82]) and non-Hispanic Black (79%, 95% CI [75, 84]) groups demonstrate reduced 5-year survival compared to non-Hispanic Whites (89%, 95% CI [86, 92]) and Floridian Hispanics (89%, 95% CI [86, 90]).

CONCLUSIONS

These findings demonstrate that Puerto Rican breast cancer patients suffer significant breast cancer health disparities relative to non-Hispanic Whites and Hispanics from Florida similar to the disparities observed for non-Hispanic Blacks. Future work must seek to better understand and address these disparities.

Targeted gene panel sequencing of liquid and tissue biopsies reveals actionable genomic alterations in Ghanaian metastatic breast cancer cases

PURPOSE

Breast cancer is a major cause of cancer-related mortality among African women. The adoption of molecular genomic technologies in the management of cancer cases is limited in Africa. To provide much-needed insights on the feasibility and utility of such precision medicine paradigms in Africa, we conducted a prospective, non-interventional study involving combined tissue and plasma Next-generation sequencing (NGS)-based testing in cancer patients in Ghana.

METHODS

We recruited 20 newly diagnosed, histologically confirmed, treatment-naïve women with metastatic breast cancer at the Cape Coast Teaching Hospital in Ghana. Tissue (NGS) and cell-free DNA (cfDNA) liquid biopsy analysis were ordered on all 20 patients.

RESULTS

All 20/20 (100 %) liquid biopsy samples were acceptable for analysis, whereas only 6/20 (30 %) passed quality control for tissue NGS testing. Liquid biopsy detected 42 cfDNA mutations in 17/20 patients. Of the 17 patients, 3 (17.6 %) had mutations previously associated with African ancestry, including BRCA1 p.K719E, ARAF p.S262I and GATA3 p.G125dup. Eight potentially actionable alterations specific to breast cancer were found in 6/17 (35.3 %) liquid biopsy samples, while potentially actionable mutations non-specific to breast cancer were detected in 12/17 (70.6 %). Tissue biopsy analysis detected mutations in all 6 patients tested, with 3/6 (50 %) patients presenting potentially actionable mutations relevant to breast cancer.

CONCLUSION

Liquid biopsy detected multiple additional actionable variants in Ghanaian women with breast cancer. Plasma cfDNA analysis featured fewer variations in sample preparation which is a key consideration in resource-limited settings. Liquid biopsy presents a great opportunity to improve cancer care in Africa.

Mitotic kinases are emerging therapeutic targets against metastatic breast cancer

This review aims to outline mitotic kinase inhibitors' roles as potential therapeutic targets and assess their suitability as a stand-alone clinical therapy or in combination with standard treatments for advanced-stage solid tumors, including triple-negative breast cancer (TNBC). Breast cancer poses a significant global health risk, with TNBC standing out as the most aggressive subtype. Comprehending the role of mitosis is crucial for understanding how TNBC advances from a solid tumor to metastasis. Chemotherapy is the primary treatment used to treat TNBC. Some types of chemotherapeutic agents target cells in mitosis, thus highlighting the need to comprehend the molecular mechanisms governing mitosis in cancer. This understanding is essential for devising targeted therapies to disrupt these mitotic processes, prevent or treat metastasis, and improve patient outcomes. Mitotic kinases like Aurora kinase A, Aurora Kinase B, never in mitosis gene A-related kinase 2, Threonine-Tyrosine kinase, and Polo-kinase 1 significantly impact cell cycle progression by contributing to chromosome separation and centrosome homeostasis. When these kinases go awry, they can trigger chromosome instability, increase cell proliferation, and activate different molecular pathways that culminate in a transition from epithelial to mesenchymal cells. Ongoing clinical trials investigate various mitotic kinase inhibitors as potential biological treatments against advanced solid tumors. While clinical trials against mitotic kinases have shown some promise in the clinic, more investigation is necessary, since they induce severe adverse effects, particularly affecting the hematopoietic system.

The VEGF-Hypoxia Signature Is Upregulated in Basal-like Breast Tumors from Women of African Ancestry and Associated with Poor Outcomes in Breast Cancer

PURPOSE

Black women experience the highest breast cancer mortality rate compared with women of other racial/ethnic groups. To gain a deeper understanding of breast cancer heterogeneity across diverse populations, we examined a VEGF-hypoxia gene expression signature in breast tumors from women of diverse ancestry.

EXPERIMENTAL DESIGN

We developed a NanoString nCounter gene expression panel and applied it to breast tumors from Nigeria (n = 182) and the University of Chicago (Chicago, IL; n = 161). We also analyzed RNA sequencing data from Nigeria (n = 84) and The Cancer Genome Atlas (TCGA) datasets (n = 863). Patient prognosis was analyzed using multiple datasets.

RESULTS

The VEGF-hypoxia signature was highest in the basal-like subtype compared with other subtypes, with greater expression in Black women compared with White women. In TCGA dataset, necrotic breast tumors had higher scores for the VEGF-hypoxia signature compared with non-necrosis tumors (P < 0.001), with the highest proportion in the basal-like subtype. Furthermore, necrotic breast tumors have higher scores for the proliferation signature, suggesting an interaction between the VEGF-hypoxia signature, proliferation, and necrosis. T-cell gene expression signatures also correlated with the VEGF-hypoxia signature when testing all tumors in TCGA dataset. Finally, we found a significant association of the VEGF-hypoxia profile with poor outcomes when using all patients in the METABRIC (P < 0.0001) and SCAN-B datasets (P = 0.002).

CONCLUSIONS

These data provide further evidence for breast cancer heterogeneity across diverse populations and molecular subtypes. Interventions selectively targeting VEGF-hypoxia and the immune microenvironment have the potential to improve overall survival in aggressive breast cancers that disproportionately impact Black women in the African Diaspora.

Is Sentinel Lymph Node Biopsy a Viable Alternative to Axillary Lymph Node Dissection in Breast Carcinoma Patients Who Have Received Neo-Adjuvant Chemotherapy?

Background Sentinel lymph node biopsy (SLNB) is based on the hypothesis that lymph from a primary solid neoplasm drains into one or more sentinel nodes, which are the first nodes at risk for harbouring occult metastatic disease. Sentinel lymph node biopsy has replaced axillary lymph node dissection (ALND) as the standard method for axillary staging in clinically node-negative patients. It avoids the complications associated with ALND and allows assessment of nodal status in patients with clinically node-negative breast cancer. Aims and objectives The aim of this study is to determine the false negative rate and identification rate of SLNB in breast cancer patients who received neoadjuvant chemotherapy (NACT). Materials and methods We conducted a hospital-based prospective study that included 19 patients who presented with early breast cancer and were node-positive. Post NACT, intraoperatively, methylene blue and radiocolloid dye were injected in the subareolar region. During the surgery, the blue and hot nodes identified were dissected, sent for frozen section analysis, and subsequently submitted for histopathological evaluation. This was followed by a standard-level I/II/III axillary clearance with histopathological examination. Results The false-negative rate of SLNB is 25%. Sentinel lymph node biopsy was more accurate with stage II than stage III tumours, and in patients who downstaged from stage II to any stage following NACT, it was more accurate than downstaging from stage III. The average number of sentinel nodes identified was 1.9, with the maximum being seven and the minimum being one. A total of 25 sentinel lymph nodes were identified in 13 patients, with an identification rate of 68.42%. Conclusions The main clinicopathological factors that influence the false negative rate of SLNB after NACT are axillary lymph node status, stage of the tumour at presentation, and tumour downstaging. For patients for whom sentinel nodes cannot be harvested, ALND should be done.

Population-specific Mutation Patterns in Breast Tumors from African American, European American, and Kenyan Patients

Women of African descent have the highest breast cancer mortality in the United States and are more likely than women from other population groups to develop an aggressive disease. It remains uncertain to what extent breast cancer in Africa is reminiscent of breast cancer in African American or European American patients. Here, we performed whole-exome sequencing of genomic DNA from 191 breast tumor and non-cancerous adjacent tissue pairs obtained from 97 African American, 69 European American, 2 Asian American, and 23 Kenyan patients. Our analysis of the sequencing data revealed an elevated tumor mutational burden in both Kenyan and African American patients, when compared with European American patients. TP53 mutations were most prevalent, particularly in African American patients, followed by PIK3CA mutations, which showed similar frequencies in European American, African American, and the Kenyan patients. Mutations targeting TBX3 were confined to European Americans and those targeting the FBXW7 tumor suppressor to African American patients whereas mutations in the ARID1A gene that are known to confer resistance to endocrine therapy were distinctively enriched among Kenyan patients. A Kyoto Encyclopedia of Genes and Genomes pathway analysis could link FBXW7 mutations to an increased mitochondrial oxidative phosphorylation capacity in tumors carrying these mutations. Finally, Catalogue of Somatic Mutations in Cancer (COSMIC) mutational signatures in tumors correlated with the occurrence of driver mutations, immune cell profiles, and neighborhood deprivation with associations ranging from being mostly modest to occasionally robust. To conclude, we found mutational profiles that were different between these patient groups. The differences concentrated among genes with low mutation frequencies in breast cancer.

SIGNIFICANCE

The study describes differences in tumor mutational profiles between African American, European American, and Kenyan breast cancer patients. It also investigates how these profiles may relate to the tumor immune environment and the neighborhood environment in which the patients had residence. Finally, it describes an overrepresentation of ARID1A gene mutations in breast tumors of the Kenyan patients.

Survival and Recurrence Patterns in Patients With Stomach Adenocarcinoma Receiving Chemotherapy or Chemoradiotherapy After D2 Gastrectomy in a Tertiary Care Cancer Institute: A Retrospective Real-World Evidence Cohort Study

Purpose

Clinical trials comparing the efficacy of adjuvant chemotherapy (CT) and chemo radiation therapy (CTRT) for stomach adenocarcinoma have reported equivocal results. Hence, the current retrospective cohort study assessed the long-term survival and recurrence outcomes of these therapies, to generate evidence in a real-world scenario.

Methods and Materials

Pathologically confirmed patients with stomach adenocarcinoma aged ≥18 years who underwent gastrectomy and D2 lymph nodal dissection at a tertiary cancer hospital from January 2010 to October 2017 were enrolled. Hospital-based follow-up was performed until December 2021. Data were gathered from electronic medical records, supplemented by telephonic interviews for patients who could not come for physical follow-up. CT-alone and CTRT cohorts were compared in terms of survival and recurrence outcomes.

Results

The analysis included 158 patients (mean age, 56.42 years; 63.9% male; CT-alone cohort, 69; CTRT cohort, 89). Patients in the CTRT cohort had significantly worse tumor characteristics at baseline (29.2% had the diffuse type of tumor, 94.4% had stage II or III, 68.5% had lympho-vascular space invasion, and 85.4% had lymph node involvement). Recurrence was observed in 13 (19.7%) of the 76 followed-up patients. Although locoregional recurrence was higher in the CT-alone cohort (7 vs 2), distant metastasis was higher in the CTRT cohort (3 vs 1). The overall 5-year survival was 67.0% (SE, 5.0%) and 5-year recurrence-free survival (RFS) was 75.0% (SE, 5.0%). On multivariate Cox regression, no variable was significantly associated with the overall survival, whereas age, positive lymph nodes without extracapsular extension, and lymph node-negative were significantly associated with RFS. The CTRT cohort had significantly (84.0%) higher RFS (hazard ratio, 0.161; 95% CI, 0.056-0.464; P < .001).

Conclusions

Patients who received adjuvant CTRT after D2 dissection showed similar overall survival but significantly higher RFS than the CT-alone cohort, despite having worse baseline tumor characteristics.

Expression Patterns of ER, PR, HER-2/neu and p53 in Association with Nottingham Tumour Grade in Breast Cancer Patients

Objectives

Recent molecular studies show that breast cancer (BC) is a heterogeneous disease, and several molecular changes may accumulate over time to influence treatment response. As a result, employing reliable molecular biomarkers to monitor these modifications may help deliver personalised treatment. However, this may be unrealistic in the resource-limited parts of the world. Thus, this study aimed to investigate the expression pattern of hormone receptors and p53 tumour suppressor using immunohistochemistry (IHC) in BC compared to the traditional tumour grade.

Methods

In total, 205 cases were investigated, and the Modified Bloom-Richardson score system was adopted in grading the tumours. The tissue sections of the cases were stained with specific primary antibodies at dilutions of 1:60 for oestrogen receptors (ER) and progesterone receptors (PR), 1:350 for the human epidermal growth factor (HER-2/neu) and 1:50 for p53.

Results

Invasive ductal carcinoma of no-specific type (n = 190, 92.7%) was predominant and grade II tumour (n = 146, 71.2%) was the most frequent. Hormone receptors ER (n = 127) and PR (n = 145) had 62.0% and 70.7% positive cases, respectively; 34.1% (n = 70) were positive for HER-2/neu, while 76.1% (n = 156) were positive for p53. Significant associations between Nottingham grade and expression patterns of ER (P <0.01), PR (P <0.001), HER-2/neu (P <0.001) and p53 (P = 0.001) were observed.

Conclusion

Nottingham grade had a high degree of concordance with the patterns of expression of hormone receptors, HER-2/neu and p53, suggesting that it may play an important role in connection with the predictive and prognostic biomarkers for BC.

Revolutionizing treatment for triple-negative breast cancer: Harnessing the power of exosomal miRNAs for targeted therapy

Triple-negative breast cancer (TNBC) represents a challenging and aggressive form of breast cancer associated with limited treatment options and poor prognosis. Although chemotherapy is a primary therapeutic approach, drug resistance often hinders treatment success. However, the expanding knowledge of TNBC subtypes and molecular biology has paved the way for targeted therapies. Notably, exosomes (extracellular vesicles) have emerged as crucial carriers of tumorigenic factors involved in oncogenesis and drug resistance, facilitating cell-to-cell communication and offering potential as self-delivery systems. Among the cargo carried by exosomes, microRNAs (miRNAs) have gained attention due to their ability to mediate epigenetic changes in recipient cells upon transfer. Research has confirmed dysregulation of exosomal miRNAs in breast cancer cells compared to healthy cells, establishing them as promising biomarkers for cancer diagnosis and prognosis. In this comprehensive review, we summarize the latest research findings that underscore the diagnostic and prognostic significance of exosomal miRNAs in TNBC treatment. Furthermore, we explore contemporary therapeutic approaches utilizing these exosomal miRNAs for the benefit of TNBC patients, shedding light on potential breakthroughs in TNBC management.

Poly(ADP-ribose) polymerase inhibitors in the treatment landscape of triple-negative breast cancer (TNBC)

OBJECTIVE

Chemotherapy is the mainstay for triple-negative breast cancer (TNBC) patients. Over the years, the use of chemotherapy for these patients has demonstrated many adversities, including toxicity and resistance, which suggested the need to develop novel alternative therapeutic options, such as poly(ADP-ribose) polymerase inhibitors (PARPi). Herein, we provide an overview on PARPi, mechanisms of action and the role of biomarkers in PARPi sensitivity trials, clinical advances in PARPi therapy for TNBC patients based on the most recent studies and findings of clinical trials, and challenges that prevent PARP inhibitors from achieving high efficacy such as resistance and overlapping toxicities with other chemotherapies.

DATA SOURCES

Searching for relevant articles was done using PubMed and Cochrane Library databases by using the keywords including TNBC; chemotherapy; PARPi; BRCA; homologous recombination repair (HRR). Studies had to be published in full-text in English in order to be considered.

DATA SUMMARY

Although PARPi have been used in the treatment of local/metastatic breast malignancies that are HER2 negative and has a germline BRCA mutation, several questions are still to be answered in order to maximize the clinical benefit of PARP inhibitors in TNBC treatment, such as questions related to the optimal use in the neoadjuvant and metastatic settings as well as the best combinations with various chemotherapies.

CONCLUSIONS

PARPi are emerging treatment options for patients with gBRCA1/2 mutations. Determining patients that are most likely to benefit from PARPi and identifying the optimal treatment combinations with high efficacy and fewer side effects are currently ongoing.

Pathologically confirmed women's breast cancer: A descriptive study of Tunisian and Algerian series

BACKGROUND

Breast cancer (BC) is the most frequent malignancy among women in Tunisia and Algeria. Clinical and pathological characteristics of this cancer among these populations are not widely reported. The aim of the study was to report clinical and pathological characteristics of women's BC in a Tunisian and Algerian series.

METHODS

Pathologically confirmed 1089 BCs were gathered in the pathology departments of three Northern Tunisian hospitals: Tunis military, Charles Nicolle and Jendouba and in the pathology department of Alger Douera hospital between January 2015 and December 2020. Clinical and pathological findings of the two series: age, tumor size, histological type, grading according to Scarff-Bloom Richardson grading system, lymph node status at the time of diagnosis in axillary lymphadenectomy specimens and the immunohistochemical expression of estrogen and progesterone receptors (ER/PR), HER2 and Ki-67, were collected from the pathological reports.

RESULTS

The median age at diagnosis was 50 and 48 years in Tunisian and Algerian series, respectively (p = 0.016). The diagnosis of BC was made on surgical specimens (lumpectomy or mastectomy) in 373/491 (76%) cases of the Tunisian series and in 225/598 (37.6%) cases of the Algerian one. Median tumor size was 2.8 cm and 2.5 cm in Algerian and Tunisian series, respectively (p = 0.252). Invasive BCs not otherwise specified was observed in 440/481 (91.5%) BCs in Tunisian series and in 519/586 (88.6%) BCs in Algerian series. Axillary lymph node positive tumors were observed in 64.6% and 58.8% of Tunisian and Algerian women, respectively (p = 0.926). BCs were ER positive in 311/385 (80.8%) and 486/571 (85.1%) cases and HER2 positive in 86/283 (30.4%) and 60/385 (15.6%) cases of Tunisian and Algerian series, respectively.

CONCLUSIONS

In Tunisia and Algeria, BC has poor prognostic factors with large tumor sizes and high rates of lymph nodes involvement at diagnosis.

Immunohistochemical and Clinicopathological Characteristics of Invasive Breast Carcinoma in Nigeria

Objectives

We aimed to study the immunohistochemical and clinicopathological characteristics of invasive breast carcinoma among Nigerian women.

Methods

We conducted a retrospective assessment of female patients diagnosed with breast carcinoma at a tertiary hospital in Nigeria between 2012 and 2019. Archived pathology request forms and processed specimens (tissue blocks and slides) were used as source data in addition to the patients' demographic and other relevant data.

Results

Reports pertaining to 113 patients were assessed. Their age range was 30 to 80 years (mean = 52.1±12.1 years). Breast carcinoma was most common in patients aged 40 to 49 years (32.7%), closely followed by those aged 50 to 59 years (30.1%). Invasive ductal carcinoma was the most common histopathological subtype (94.7%). Nottingham grade III and grade II breast carcinoma accounted for 41.6% and 40.7% of the cases, respectively. Mastectomy specimens formed 68.1% of the samples. The most common tumor size (75.9%) was > 5cm (mean = 6.8±3.2cm), consistent with the most common staging of T3 (46.0%). The most common lymph node involvement was N1 (56.6%). Immunohistochemical assessment of these tumors with estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 (HER-2) biomarkers expressed positivity of 36.3%, 28.3%, and 41.6%, respectively. These tumors were immunohistochemically classified into luminal A (16.8%), luminal B (20.4%), HER-2 enriched (20.4%), and triple-negative (42.5%) subtypes.

Conclusions

The most common immunohistochemical subtype of invasive breast carcinoma among this sample of Nigerian women was the triple-negative subtype, similar to the finding among African Americans.

Advancing Breast Cancer Heterogeneity Analysis: Insights from Genomics, Transcriptomics and Proteomics at Bulk and Single-Cell Levels

Breast cancer continues to pose a significant healthcare challenge worldwide for its inherent molecular heterogeneity. This review offers an in-depth assessment of the molecular profiling undertaken to understand this heterogeneity, focusing on multi-omics strategies applied both in traditional bulk and single-cell levels. Genomic investigations have profoundly informed our comprehension of breast cancer, enabling its categorization into six intrinsic molecular subtypes. Beyond genomics, transcriptomics has rendered deeper insights into the gene expression landscape of breast cancer cells. It has also facilitated the formulation of more precise predictive and prognostic models, thereby enriching the field of personalized medicine in breast cancer. The comparison between traditional and single-cell transcriptomics has identified unique gene expression patterns and facilitated the understanding of cell-to-cell variability. Proteomics provides further insights into breast cancer subtypes by illuminating intricate protein expression patterns and their post-translational modifications. The adoption of single-cell proteomics has been instrumental in this regard, revealing the complex dynamics of protein regulation and interaction. Despite these advancements, this review underscores the need for a holistic integration of multiple 'omics' strategies to fully decipher breast cancer heterogeneity. Such integration not only ensures a comprehensive understanding of breast cancer's molecular complexities, but also promotes the development of personalized treatment strategies.

Development and testing of a polygenic risk score for breast cancer aggressiveness

Aggressive breast cancers portend a poor prognosis, but current polygenic risk scores (PRSs) for breast cancer do not reliably predict aggressive cancers. Aggressiveness can be effectively recapitulated using tumor gene expression profiling. Thus, we sought to develop a PRS for the risk of recurrence score weighted on proliferation (ROR-P), an established prognostic signature. Using 2363 breast cancers with tumor gene expression data and single nucleotide polymorphism (SNP) genotypes, we examined the associations between ROR-P and known breast cancer susceptibility SNPs using linear regression models. We constructed PRSs based on varying p-value thresholds and selected the optimal PRS based on model r2 in 5-fold cross-validation. We then used Cox proportional hazards regression to test the ROR-P PRS's association with breast cancer-specific survival in two independent cohorts totaling 10,196 breast cancers and 785 events. In meta-analysis of these cohorts, higher ROR-P PRS was associated with worse survival, HR per SD = 1.13 (95% CI 1.06-1.21, p = 4.0 × 10-4). The ROR-P PRS had a similar magnitude of effect on survival as a comparator PRS for estrogen receptor (ER)-negative versus positive cancer risk (PRSER-/ER+). Furthermore, its effect was minimally attenuated when adjusted for PRSER-/ER+, suggesting that the ROR-P PRS provides additional prognostic information beyond ER status. In summary, we used integrated analysis of germline SNP and tumor gene expression data to construct a PRS associated with aggressive tumor biology and worse survival. These findings could potentially enhance risk stratification for breast cancer screening and prevention.

Integration of clinical features and deep learning on pathology for the prediction of breast cancer recurrence assays and risk of recurrence

Gene expression-based recurrence assays are strongly recommended to guide the use of chemotherapy in hormone receptor-positive, HER2-negative breast cancer, but such testing is expensive, can contribute to delays in care, and may not be available in low-resource settings. Here, we describe the training and independent validation of a deep learning model that predicts recurrence assay result and risk of recurrence using both digital histology and clinical risk factors. We demonstrate that this approach outperforms an established clinical nomogram (area under the receiver operating characteristic curve of 0.83 versus 0.76 in an external validation cohort, p = 0.0005) and can identify a subset of patients with excellent prognoses who may not need further genomic testing.

Immunohistochemical Profiling of HER-2/neu, Steroid Hormone Receptors and KI-67 Biomarkers in A Cohort of Nigerian Women with Breast Cancer

Background

Progressive improvement in the accuracy of profiling of hormone receptors in breast cancer provides the basis for targeted endocrine therapy, a major pillar of multimodal breast cancer treatment. However, the disparity in findings from comparatively smaller sample-sized studies in West Africa has led to somewhat conflicting conclusions and recommendations.

Objectives

This study investigates the immunohistochemical (IHC) profile of breast cancer specimens for estrogen receptor (ER), progesterone receptor (PR), human epidermal receptor-2 (HER2)/neu, and Ki-67 in a tertiary hospital in Ibadan, Nigeria over 12 years.

Materials and Methods

We reviewed 998 IHC reports, documented clinicopathologic parameters, computed patterns of biomarkers, and stratified them based on the American Society of Clinical Oncology/College of American Pathologists recommendations. Descriptive analysis including frequency, mean, and median were generated from the data extracted.

Results

Out of the 998 cases, 975 (97.7%) were females and 23 (2.3%) were males. The mean age was 48.84 ± 11.99 years. Open biopsies were the most common types of specimens (320, 41.6%): lumpectomy and incisional biopsy of ulcerated, fungating or unresectable tumours. In those cases, 246 (32.0%) were samples of breast-conserving or ablative surgical extirpation (mastectomy/wide local excision/quadrantectomy), and 203 (26.4%) were obtained by core needle biopsies. Invasive ductal carcinoma was the most common histopathological type (673, 94.5%). The majority of graded tumours were intermediate grade (444, 53.5%). Four hundred and sixty-nine (48.4%) were ER positive, 414 (42.8%) were PR positive, and 180 (19.4%) were HER2/neu positive. Three hundred and thirty-four (34.0%) were triple-negative. Eighty-nine cases had Ki-67 staining done, and of these 61 (68.5%) had positive nuclear staining.

Conclusion

Steroid hormone receptors and HER-2/neu proportions in our cohort are likely to be more representative than the widely varied figures hitherto reported in the sub-region. We advocate routine IHC analysis of breast cancer samples as a guide to personalized endocrine therapy.

Neighborhood and racial influences on triple negative breast cancer: evidence from Northeast Ohio

PURPOSE

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC) with higher recurrence rates and poorer prognoses and most prevalent among non-Hispanic Black women. Studies of multiple health conditions and care processes suggest that neighborhood socioeconomic position is a key driver of health disparities. We examined roles of patients' neighborhood-level characteristics and race on prevalence, stage at diagnosis, and mortality among patients diagnosed with BC at a large safety-net healthcare system in Northeast Ohio.

METHODS

We used tumor registry to identify BC cases from 2007 to 2020 and electronic health records and American Community Survey for individual- and area-level factors. We performed multivariable regression analyses to estimate associations between neighborhood-level characteristics, measured by the Area Deprivation Index (ADI), race and comparative TNBC prevalence, stage at diagnosis, and total mortality.

RESULTS

TNBC was more common among non-Hispanic Black (53.7%) vs. non-Hispanic white patients (46.4%). Race and ADI were individually significant predictors of TNBC prevalence, stage at diagnosis, and total mortality. Race remained significantly associated with TNBC subtype, adjusting for covariates. Accounting for TNBC status, a more disadvantaged neighborhood was significantly associated with a worse stage at diagnosis and higher death rates.

CONCLUSION

Our findings suggest that both neighborhood socioeconomic position and race are strongly associated with TNBC vs. other BC subtypes. The burden of TNBC appears to be highest among Black women in the most socioeconomically disadvantaged neighborhoods. Our study suggests a complex interplay of social conditions and biological disease characteristics contributing to racial disparities in BC outcomes.

Validation of the Nigerian Breast Cancer Study Model for Predicting Individual Breast Cancer Risk in Cameroon and Uganda

BACKGROUND

The Nigerian Breast Cancer Study (NBCS) model is a new risk assessment tool developed for predicting risk of invasive breast cancer in Nigeria. Its applicability outside of Nigeria remains uncertain as it has not been validated in other sub-Saharan Africa populations.

METHODS

We conducted a case-control study among women with breast cancer and controls ascertained in Cameroon and Uganda from 2011 to 2016. Structured questionnaire interviews were performed to collect risk factor characteristics. The NBCS model, the Gail model, the Gail model for Black population, and the Black Women's Health Study model were applied to the Cameroon and Uganda samples separately. Nigerian as well as local incidence rates were incorporated into the models. Receiver-Operating Characteristic analyses were performed to indicate discriminating capacity.

RESULTS

The study included 550 cases (mean age 46.8 ± 11.9) and 509 controls (mean age 46.3 ± 11.7). Compared with the other three models, the NBCS model performed best in both countries. The discriminating accuracy of the NBCS model in Cameroon (age-adjusted C-index = 0.602; 95% CI, 0.542-0.661) was better than in Uganda (age-adjusted C-index = 0.531; 95% CI, 0.459-0.603).

CONCLUSIONS

These findings demonstrate the potential clinical utility of the NBCS model for risk assessment in Cameroon. All currently available models performed poorly in Uganda, which suggests that the NBCS model may need further calibration before use in other regions of Africa.

IMPACT

Differences in risk profiles across the African diaspora underscores the need for larger studies and may require development of region-specific risk assessment tools for breast cancer.

A randomized phase 2 study of neoadjuvant carboplatin and paclitaxel with or without atezolizumab in triple negative breast cancer (TNBC) - NCI 10013

Atezolizumab with chemotherapy has shown improved progression-free and overall survival in patients with metastatic PD-L1 positive triple negative breast cancer (TNBC). Atezolizumab with anthracycline- and taxane-based neoadjuvant chemotherapy has also shown increased pathological complete response (pCR) rates in early TNBC. This trial evaluated neoadjuvant carboplatin and paclitaxel with or without atezolizumab in patients with clinical stages II-III TNBC. The co-primary objectives were to evaluate if chemotherapy and atezolizumab increase pCR rate and tumor infiltrating lymphocyte (TIL) percentage compared to chemotherapy alone in the mITT population. Sixty-seven patients (ages 25-78 years; median, 52 years) were randomly assigned - 22 patients to Arm A, and 45 to Arm B. Median follow up was 6.6 months. In the modified intent to treat population (all patients evaluable for the primary endpoints who received at least one dose of combination therapy), the pCR rate was 18.8% (95% CI 4.0-45.6%) in Arm A, and 55.6% (95% CI 40.0-70.4%) in Arm B (estimated treatment difference: 36.8%, 95% CI 8.5-56.6%; p = 0.018). Grade 3 or higher treatment-related adverse events occurred in 62.5% of patients in Arm A, and 57.8% of patients in Arm B. One patient in Arm B died from recurrent disease during the follow-up period. TIL percentage increased slightly from baseline to cycle 1 in both Arm A (mean ± SD: 0.6% ± 21.0%) and Arm B (5.7% ± 15.8%) (p = 0.36). Patients with pCR had higher median TIL percentages (24.8%) than those with non-pCR (14.2%) (p = 0.02). Although subgroup analyses were limited by the small sample size, PD-L1-positive patients treated with chemotherapy and atezolizumab had a pCR rate of 75% (12/16). The addition of atezolizumab to neoadjuvant carboplatin and paclitaxel resulted in a statistically significant and clinically relevant increased pCR rate in patients with clinical stages II and III TNBC. (Funded by National Cancer Institute).

Ethnic and racial-specific differences in levels of centrosome-associated mitotic kinases, proliferative and epithelial-to-mesenchymal markers in breast cancers

Molecular epidemiology evidence indicates racial and ethnic differences in the aggressiveness and survival of breast cancer. Hispanics/Latinas (H/Ls) and non-Hispanic Black women (NHB) are at higher risk of breast cancer (BC)-related death relative to non-Hispanic white (NHW) women in part because they are diagnosed with hormone receptor-negative (HR) subtype and at higher stages. Since the cell cycle is one of the most commonly deregulated cellular processes in cancer, we propose that the mitotic kinases TTK (or Mps1), TBK1, and Nek2 could be novel targets to prevent breast cancer progression among NHBs and H/Ls. In this study, we calculated levels of TTK, p-TBK1, epithelial (E-cadherin), mesenchymal (Vimentin), and proliferation (Ki67) markers through immunohistochemical (IHC) staining of breast cancer tissue microarrays (TMAs) that includes samples from 6 regions in the Southeast of the United States and Puerto Rico -regions enriched with NHB and H/L breast cancer patients. IHC analysis showed that TTK, Ki67, and Vimentin were significantly expressed in triple-negative (TNBC) tumors relative to other subtypes, while E-cadherin showed decreased expression. TTK correlated with all of the clinical variables but p-TBK1 did not correlate with any of them. TCGA analysis revealed that the mRNA levels of multiple mitotic kinases, including TTK, Nek2, Plk1, Bub1, and Aurora kinases A and B, and transcription factors that are known to control the expression of these kinases (e.g. FoxM1 and E2F1-3) were upregulated in NHBs versus NHWs and correlated with higher aneuploidy indexes in NHB, suggesting that these mitotic kinases may be future novel targets for breast cancer treatment in NHB women.

Race and Ancestry in Immune Response to Breast Cancer

Martini and colleagues performed genetic ancestry estimation on a unique international triple-negative breast cancer (TNBC) study enriched for participants with African ancestry. They identified gene signatures indicative of ancestry in race-associated TNBC and found ancestry-associated immunologic differences that may contribute to racial disparities in breast cancer. See related article by Martini et al., p. 2530 (5).

Epidemiology of Breast Cancer Presentation in Botswana, South Africa, and the United States

INTRODUCTION

This study sought to compare the clinicopathologic features of women with breast cancer presenting in South Africa, Botswana, and the United States (US).

METHODS

Breast cancer samples from Botswana (n = 384, 2011-2015), South Africa (n = 475, 2016-2017), and the US (n = 361,353, 2011-2012) were retrospectively reviewed.

RESULTS

The median age of sub-Saharan African women presenting with breast cancer (age 54 in Botswana and South Africa) was younger than that of those in the US (age 61) (P < 0.001). Sub-Saharan women were more likely to present with advanced stage disease than US counterparts (64.7% in Botswana, 63.3% in South Africa, 13% in the US, P < 0.001). Triple negative disease was highest in Botswana (21.3%) compared to South Africa (11.4%) and the US (12.94%) (P < 0.001). Differences in receptor status at presentation among the three cohorts (P < 0.001) were not observed when the cohorts were stratified by ethnicity. Black/multiracial patients in Botswana and the US were the most likely subsets to present with the adverse characteristic of triple negative disease (21.3% and 23.2%, respectively). No correlation was found between HIV and receptor status in the Botswana (P = 0.513) or South African (P = 0.352) cohorts.

CONCLUSIONS

Here we report receptor status patterns at presentation in Botswana and South Africa. This study reveals important similarities and differences which may inform policy and provide context for future epidemiologic trends of breast cancer in low- and-middle-income countries particularly in sub-Saharan Africa.

Galectin-3 as a biomarker in breast neoplasms: Mechanisms and applications in patient care

Galectin-3 is a member of the lectin family encoded by the LGALS3 gene on chromosome 14. It is secreted by a wide range of immune cells and mammary tumor cells. Through its activity on the tumor microenvironment, in particular on tumor-infiltrating leukocytes, galectin-3 improves the proliferation, survival, and colonizing ability of mammary neoplastic cells. Consequently, galectin-3 expression in the tumor microenvironment could worsen therapeutic outcomes of breast neoplasms and become a biomarker and a therapeutic target in combined immunotherapy in breast neoplasms. There is a limited amount of information that is available on galectin-3 in breast cancer in Africa. In this review, we analyze how galectin-3 influences the tumor microenvironment and its potential as a biomarker and therapeutic target in breast neoplasms. We aim to emphasize the significance of investigating galectin-3 in breast neoplasms in Africa based on the results of studies conducted elsewhere.

Clinicopathological features and androgen receptor expression in triple negative breast cancer at Lagos, Nigeria

INTRODUCTION

Androgen receptor (AR) is one of the predominant nuclear hormone receptors in invasive breast cancer and can be explored as a biomarker of response for targeted anti-androgen therapy, especially in the setting of triple negative breast cancer (TNBC). Luminal AR is a distinct subtype amongst TNBC cases following gene expression studies. TNBC is higher in Africans (23%-82%) and African-Americans (29.8%) compared to Caucasian (10%-15%) breast cancer patients; however, there is a paucity of data on AR expression in this population. The aim of this study is to determine the expression of AR and the proportion of AR positive cancers in TNBCs at the Lagos University Teaching Hospital, Lagos, Nigeria.

METHODOLOGY

Out of 99 reviewed cases, 78 formalin fixed, paraffin embedded TNBC cases were assembled into a tissue microarray, stained and analysed for AR expression using immunohistochemistry.

RESULTS

The mean age of the TNBC patients was 49.3 years (range: 20-80 years). The histologic types in this study were invasive carcinoma (no special type) 75.4%; metaplastic carcinoma 21.4%; lobular carcinoma and mucinous carcinoma 1.6% each. Of 61 TNBC cases analysed, 37.7% were AR positive and 62.3% were AR negative, making the latter to become quadruple negative breast cancers. There was a significant association between age and AR expression (p = 0.02). In the subjects that expressed AR positivity, patients below 50 years accounted for 34.8% (8 of 23) while 65.2% (15 of 23) were above 50 years. There was no significant association between AR expression and histologic type or tumour grade.

CONCLUSION

Over a third of this Nigerian TNBC cohort study is AR+. This warrants further exploration of the predictive and prognostic significance of its expression amongst TNBC and the potential for targeted therapy, specifically androgen antagonists to improve the outcome of this disease with limited therapeutic options.

Leisure-time physical activity is associated with reduced risks of breast cancer and triple negative breast cancer in Nigerian women

BACKGROUND

Leisure-time physical activity(LTPA) is associated with a reduced risk of breast cancer, but this has less been investigated by cancer subtypes in Africans living in Sub-Saharan Africa(SSA). We examined the associations between LTPA and breast cancer including its subtypes in Nigerian women and explored the effect modification of body size on such associations.

METHODS

The sample included 508 newly diagnosed primary invasive breast cancer cases and 892 controls from the Nigerian Integrative Epidemiology of Breast Cancer(NIBBLE) Study. Immunohistochemical(IHC) analysis was available for 294 cases. Total metabolic equivalents(METs) per hour/week of LTPA were calculated and divided by quartiles(Q1 <3.75, Q2:3.75-6.69, Q3:6.70-14.74, Q4:14.75 ≤). We applied logistic regressions to estimate the adjusted Odds Ratios(ORs) between LTPA and breast cancer and by its molecular subtypes and whether age-adjusted associations are modified by BMI.

RESULTS

The mean age(Mean±SD) of cases vs. controls(45.5 ± 11.1vs.40.1 ± 9.0) was higher, and the mean total METs hour/week was higher in controls vs. cases(11.9 ± 14.9vs.8.3 ± 11.1,p-value<0.001). Overall, 43.2%(N = 127/294) were classified as HRP, and 41.8%(N = 123/294) as TNBC. Women in the higher LTPA quartiles(Q3-Q4) vs. Q1 had lower odds of having breast cancer(OR_Q4vs.Q1=0.51,95%CI:0.35-0.74) and TNBC(OR_Q4vs.Q1=0.51, 95%CI:0.27-0.96), but not HRP(OR_Q4vs.Q1=0.61,95%CI:0.34-1.09) after adjusting for age, age at first menarche, body size, breastfeeding, menopausal, parity, contraceptives, demographics, alcohol, smoking, and physical activity at home and work. Lastly, LTPA and its age-adjusted association with breast cancer was more pronounced in women with BMI< 30 vs. BMI 30 + .

CONCLUSIONS

LTPA may reduce the risk of breast cancer, especially TNBC, which is the more aggressive and prevalent molecular subtype of breast cancer in SSA.

Breast Carcinoma Receptor Expression in a Caribbean Population

Trinidad and Tobago are islands in the Southern Caribbean with a unique mix of races within the population consisting of East Indian (EI) (37.6%), Afro-Caribbean (AC) (36.3%), mixed (24.2%), and Caucasian, Chinese, Lebanese, Syrian, Amerindian, and Spanish groups accounting for 1.9%. It makes it suitable for a comparison of breast carcinoma receptor expression within a fixed environment. This study included 257 women with an age range of 28 to 93 years (mean = 57.2, standard deviation = 15.0), peak age group of 51 to 60 consisting of 105 EI, 119 AC, and 33 mixed descent. Invasive ductal carcinoma accounted for 88%, invasive lobular 9.7%, and ductal carcinoma in situ 2.3%. The triple-negative rates were 24.8, 33.6, and 30.3% for EI, AC, and mixed races, respectively, with the Pearson's chi-square test revealing statistical significance for the AC versus EI ( p  < 0.001); AC versus mixed ( p  < 0.001); and EI versus mixed ( p  = 0.014) groups. The overall estrogen (ER), progesterone (PR), and human epidermal growth receptor (HER) expression negative rates were 52, 64, and 79%, respectively. Chi-square test of the following combinations: ER +/PR +/HER + ; ER +/PR +/HER − ; ER −/PR −/HER + ; ER +/PR −/HER + ; ER +/PR −/HER − ; ER −/PR +/HER + ; ER −/PR +/HER− revealed no statistical differences ( p  = 0.689).

Subtype-specific expression of MELK is partly due to copy number alterations in breast cancer

Maternal embryonic leucine-zipper kinase (MELK) regulates cell cycle progression and is highly expressed in many cancers. The molecular mechanism of MELK dysregulation has not been determined in aggressive forms of breast cancer, such as triple negative breast cancer (TNBC). To evaluate molecular markers of MELK aberrations in aggressive breast cancer, we assessed MELK gene amplification and expression in breast tumors. MELK mRNA expression is highly up-regulated in basal-like breast cancer (BLBC), the major molecular subtype of TNBC, compared to luminal or other subtypes of breast tumors. MELK copy number (CN) gains are significantly associated with BLBC, whereas no significant association of CpG site methylation or histone modifications with breast cancer subtypes was observed. Accordingly, the CN gains appear to contribute to an increase in MELK expression, with a significant correlation between mRNA expression and CN in breast tumors and cell lines. Furthermore, immunohistochemistry (IHC) assays revealed that both nuclear and cytoplasmic staining scores of MELK were significantly higher in invasive ductal carcinoma (IDC) tumors compared to ductal carcinoma in situ (DCIS) and normal breast tissues. Our data showed that upregulation of MELK in BLBC may be in part driven by CN gains, rather than epigenetic modifications, indicating a potential for overexpression and CN gains of MELK to be developed as a diagnostic and prognostic marker to identify patients who have more aggressive breast cancer.

Triple-negative breast cancer prevalence in Africa: a systematic review and meta-analysis

OBJECTIVE

The aggressive triple-negative breast cancer (TNBC) subtype disproportionately affects women of African ancestry across the diaspora, but its frequency across Africa has not been widely studied. This study seeks to estimate the frequency of TNBC among African populations.

DESIGN

Systematic review and meta-analysis using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

DATA SOURCES

PubMed, EMBASE, African Journals Online and Web of Science were searched on 25 April 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included studies that use breast cancer tissue samples from indigenous African women with sample size of eligible participants ≥40 and full receptor status for all three receptors (oestrogen receptor (ER)/progesterone receptor (PR)/human epidermal growth factor receptor 2 (HER2)) reported.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed risk of bias using the modified assessment tool by Hoy et al. (2012) for prevalence studies. A random-effects meta-analysis was performed, and data were pooled using the inverse-variance method and logit transformation. Pooled frequencies were reported with 95% CIs calculated with the Clopper-Pearson method and heterogeneity quantified with I² statistic. GRADE assessed the certainty of the evidence.

RESULTS

1808 potentially eligible studies were identified of which 67 were included in the systematic review and 60 were included in the meta- analysis. Pooled TNBC frequency across African countries represented was estimated to be 27.0%; 95% CI: 24.0% to 30.2%, I²=94%. Pooled TNBC frequency was highest across West Africa, 45.7% (n=15, 95% CI: 38.8% to 52.8%, I²=91%) and lowest in Central Africa, 14.9% (n=1, 95% CI: 8.9 % to 24.1%). Estimates for TNBC were higher for studies that used Allred guidelines for ER/PR status compared with American Society of Clinical Oncology(ASCO)/College of American Pathologists(CAP) guidelines, and for studies that used older versions of ASCO/CAP guidelines for assessing HER2 status. Certainty of evidence was assessed to be very low using GRADE approach.

CONCLUSION

TNBC frequency was variable with the highest frequency reported in West Africa. Greater emphasis should be placed on establishing protocols for assessing receptor status due to the variability among studies.

The African Female Breast Cancer Epidemiology Study Protocol

Breast cancer is now the commonest cancer in most sub-Saharan African countries. Few studies of the epidemiology and genomics of breast cancer and its molecular subtypes in these countries have been done. The African Female Breast Cancer Epidemiology (AFBRECANE) study, a part of the Human Heredity and Health in Africa (H3Africa) initiative, is designed to study the genomics and epidemiology of breast cancer and its molecular subtypes in Nigerian women. We link recruitment of breast cancer cases at study sites with population-based cancer registries activities to enable ascertainment of the incidence of breast cancer and its molecular subtypes. We use centralized laboratory processing to characterize the histopathological and molecular diagnosis of breast cancer and its subtypes using multiple technologies. By combining genome-wide association study (GWAS) data from this study with that generated from 12,000 women participating in our prospective cohort study of cervical cancer, we conduct GWAS of breast cancer in an entirely indigenous African population. We test associations between dietary intakes and breast cancer and focus on vitamin D which we measure using dietary intakes, serum vitamin D, and Mendelian randomization. This paper describes the AFBRECANE project, its design, objectives and anticipated contributions to knowledge and understanding of breast cancer.

Incidence of breast cancer subtypes in immigrant and non-immigrant women in Norway

BACKGROUND

Breast cancer incidence differs between non-immigrants and immigrants from low- and middle-income countries. This study investigates whether immigrants also have different subtype-specific incidences.

METHODS

We used national health registries in Norway and calculated subtype-specific incidence rate ratios (IRRs) for invasive breast cancer among women aged 20-75 and 20-49 years between 2005 and 2015. Immigrant groups were classified by country of birth broadly defined based on WHO regional groupings. Subtype was defined using estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2) status as luminal A-like (ER+ PR+ HER2-), luminal B-like/HER2- (ER+ PR- HER2-), luminal B-like/HER2+ (ER+ PR any HER2+), HER2+ (ER-PR-HER2+) and triple-negative breast cancer (TNBC) (ER-PR-HER2-).

RESULTS

Compared to non-immigrants, incidence of the luminal A-like subtype was lower in immigrants from Sub-Saharan Africa (IRR 0.43 95% CI 0.28-0.66), South East Asia (IRR 0.63 95% CI 0.51-0.79), South Asia (IRR 0.67 95% CI 0.52-0.86) and Eastern Europe (IRR 0.86 95% CI 0.76-0.99). Immigrants from South Asia had higher rates of HER2 + tumors (IRR 2.02 95% CI 1.26-3.23). The rates of TNBC tended to be similar regardless of region of birth, except that women from South East Asia had an IRR of 0.54 (95% CI 0.32-0.91).

CONCLUSIONS

Women from Eastern Europe, Sub-Saharan Africa and Asia had different subtype-specific incidences compared to women from high-income countries (including non-immigrants). These differences in tumor characteristics between immigrant groups should be taken into consideration when planning preventive or screening strategies.

In vitro effect of PIK3CA/mTOR inhibition in triple-negative breast cancer subtype cell lines

BACKGROUND

Agents targeting the PI3K pathway in triple negative breast cancer did not show any significant efficacy so far mostly because of the complex nature of these targeted inhibitors. Targeting the cancer cells with the combination of inhibitors may help in decelerating the regulatory pathways further achieving optimum clinical benefit. In this study, we investigated the effect of PIK3CA and mTOR inhibition in-vitro in triple-negative breast cancer (TNBC) cell lines.

OBJECTIVE AND METHODS

Three TNBC cell lines; MDA MB231, MDA MB468, and MDA MB453 were subtyped using immunohistochemistry and were screened for hotspot mutations in PIK3CA and AKT1. All cell lines were treated with different concentrations of inhibitors; PI3K inhibitor (BKM 120), mTOR inhibitor (AZD 8055), and dual PI3K/mTOR inhibitor (BEZ 235), and cell viability was assessed by MTT (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide), Trypan blue and Annexin-V/PI Assays.

RESULTS

Using immunohistochemistry, TNBC cell lines were subtyped as; mesenchymal subtype-specific cell line (MDA MB231), basal subtype-specific cell line (MDA MD468), and Luminal androgen receptor (LAR) subtype-specific cell line (MDA MB453). PIK3CA hot spot mutation (p.H1047R) in exon 20 was identified in the Luminal androgen receptor subtype (MDA MB453 cells) cell line. Cell viability assays showed that the Mesenchymal subtype-specific cell line (MDA MB231) was the most resistant to all inhibitors and the Luminal Androgen subtype (MDA MB453 cells) cell line was more sensitive to BKM120 (PI3K inhibitor) inhibition compared to other subtypes.

CONCLUSIONS

This study identified that the Luminal androgen receptor subtype of triple-negative breast cancer with PIK3CA mutation may be targeted with PIK3CA inhibitors with a favorable outcome.

Whole-genome analysis of Nigerian patients with breast cancer reveals ethnic-driven somatic evolution and distinct genomic subtypes

Black women across the African diaspora experience more aggressive breast cancer with higher mortality rates than white women of European ancestry. Although inter-ethnic germline variation is known, differential somatic evolution has not been investigated in detail. Analysis of deep whole genomes of 97 breast cancers, with RNA-seq in a subset, from women in Nigeria in comparison with The Cancer Genome Atlas (n = 76) reveal a higher rate of genomic instability and increased intra-tumoral heterogeneity as well as a unique genomic subtype defined by early clonal GATA3 mutations with a 10.5-year younger age at diagnosis. We also find non-coding mutations in bona fide drivers (ZNF217 and SYPL1) and a previously unreported INDEL signature strongly associated with African ancestry proportion, underscoring the need to expand inclusion of diverse populations in biomedical research. Finally, we demonstrate that characterizing tumors for homologous recombination deficiency has significant clinical relevance in stratifying patients for potentially life-saving therapies.

Breast cancer heterogeneity and tumour evolutionary trajectories remain largely unknown among women of African ancestry. Here, the authors perform whole genome and transcriptome sequencing of Nigerian breast cancer patients and identify unique evolutionary phenomena.

Patterns of care of breast cancer patients in Morocco - A study of variations in patient profile, tumour characteristics and standard of care over a decade

Guided by a national cancer plan (2010-19), Morocco made significant investments in improving breast cancer detection and treatment. A breast cancer pattern-of-care study was conducted to document the socio-demographic profiles of patients and tumour characteristics, measure delays in care, and assess the status of dissemination and impact of state-of-the-art management. The retrospective study conducted among 2120 breast cancer patients registered during 2008-17 at the two premier-most oncology centres (Centre Mohammed VI or CM-VI and Institut National d'Oncologie or INO) also measured temporal trends of the different variables. Median age (49 years) and other socio-demographic characteristics of the patients remained constant over time. A significant improvement in coverage of the state-financed health insurance scheme for indigent populations was observed over time. Median interval between onset of symptoms and first medical consultation was 6 months with a significant reduction over time. Information on staging and molecular profile were available for more than 90% and 80% of the patients respectively. Approximately 55% of the patients presented at stage I/II and proportion of triple-negative cancers was 16%; neither showing any appreciable temporal variation. Treatment information was available for more than 90% of the patients; 69% received surgery with chemotherapy and/or radiation. Treatment was tailored to stage and molecular profiles, though breast conservation therapy was offered to less than one-fifth. When compared using the EUSOMA quality indicators for breast cancer management, INO performed better than CM-VI. This was reflected in nearly 25% difference in 5-year disease-free survival for early-stage cancers between the centres.

Association of body composition with odds of breast cancer by molecular subtype: analysis of the Mechanisms for Established and Novel Risk Factors for Breast Cancer in Nigerian Women (MEND) study

BACKGROUND

The association between obesity and breast cancer (BC) has been extensively studied among US, European and Asian study populations, with often conflicting evidence. However, despite the increasing prevalence of obesity and associated conditions in Africa, the continent with the highest age-standardized BC mortality rate globally, few studies have evaluated this association, and none has examined in relation to molecular subtypes among African women. The current analysis examines the association between body composition, defined by body mass index (BMI), height, and weight, and BC by molecular subtype among African women.

METHODS

We estimated odds ratios (ORs) and 95% confidence intervals (95% CI) for the association between measures of body composition and BC and molecular subtypes among 419 histologically confirmed cases of BC and 286 healthy controls from the Mechanisms for Established and Novel Risk Factors for Breast Cancer in Women of Nigerian Descent (MEND) case-control study.

RESULTS

Higher BMI (aOR: 0.79; 95% CI: 0.67, 0.95) and weight (aOR: 0.83; 95% CI: 0.69, 0.98) were associated with reduced odds of BC in adjusted models, while height was associated with non-statistically significant increased odds of BC (aOR: 1.07, 95% CI: 0.90, 1.28). In pre/peri-menopausal, but not post-menopausal women, both higher BMI and weight were significantly associated with reduced odds of BC. Further, higher BMI was associated with reduced odds of Luminal A, Luminal B, and HER2-enriched BC among pre/peri-menopausal women, and reduced odds of triple-negative BC among post-menopausal women.

CONCLUSIONS

Higher BMI and weight were associated with reduced odds of BC overall and by molecular subtype among West African women. Larger studies of women of African descent are needed to definitively characterize these associations and inform cancer prevention strategies.

Survival Outcomes of Breast Cancer in Sudanese Women: A Hospital-Based Study

PURPOSE

Breast cancer (BC) is the leading malignancy among Sudanese women. Yet, data on survival are limited. This study aimed to determine 5-year overall survival (OS) of BC in Sudanese women, and identify prognostic demographic and clinicopathologic factors.

PATIENTS AND METHODS

A hospital-based retrospective study was conducted by reviewing data of women with BC diagnosed and treated at the National Cancer Institute—University of Gezira during 2012, and followed up to end of August 2018. Data were retrieved from medical records and analyzed, OS was determined, and the prognostic factors were explored.

RESULTS

A total of 225 cases were recruited. The median age at presentation was 45 years (range, 22-85 years). Clinical stage I, II, III, and IV represented 3.1%, 31.6%, 48%, and 17.3%, respectively. Most women (81.3%) were treated with curative intent. Of those, 25.1% received neoadjuvant chemotherapy. Mastectomy was the commonest (61.7%) type of surgery. The median follow-up period was 59.8 months with mean OS time of 55.7 months. The 5-year cumulative survival rate was 58%. The 5-year OS rates for stages I, II, III, and IV were 71.5%, 82.4%, 56.5%, and 8.4%, respectively. For lymph node (LN)-positive cases, 5-year OS rate was 63% and for LN-negative was 83.5%. Presenting with advanced-stage disease and positive LN status associated with short OS times (P < .005).

CONCLUSION

OS of women with BC in Central Sudan is worse than in the developed world, but similar to African countries. Our findings indicate that advanced stage at diagnosis and lymph nodal involvement are strong predictors of short survival times. Raising awareness and introducing early detection programs are critical for better survival of these patients.

The impact of site-specific digital histology signatures on deep learning model accuracy and bias

The Cancer Genome Atlas (TCGA) is one of the largest biorepositories of digital histology. Deep learning (DL) models have been trained on TCGA to predict numerous features directly from histology, including survival, gene expression patterns, and driver mutations. However, we demonstrate that these features vary substantially across tissue submitting sites in TCGA for over 3,000 patients with six cancer subtypes. Additionally, we show that histologic image differences between submitting sites can easily be identified with DL. Site detection remains possible despite commonly used color normalization and augmentation methods, and we quantify the image characteristics constituting this site-specific digital histology signature. We demonstrate that these site-specific signatures lead to biased accuracy for prediction of features including survival, genomic mutations, and tumor stage. Furthermore, ethnicity can also be inferred from site-specific signatures, which must be accounted for to ensure equitable application of DL. These site-specific signatures can lead to overoptimistic estimates of model performance, and we propose a quadratic programming method that abrogates this bias by ensuring models are not trained and validated on samples from the same site.

Building a breast cancer detection and treatment platform in the Democratic Republic of the Congo by integrating training, service and infrastructure development

Background

Breast cancer is a leading cause of cancer-related morbidity and mortality in sub-Saharan Africa, a global region where opportunities for breast care of any type are extremely limited due to insufficient infrastructure, a paucity of clinical services and vast shortages of trained human resources.

Methods

A team of Zambian and US gynaecologic and breast oncology experts and nurse-specialists made multiple visits (each lasting 5 working days) to the Democratic Republic of the Congo (DRC), over a 2-year period. During each of five week-long site visits, hands-on training of local Congolese health providers was conducted during which time they were taught clinical breast exam (CBE), breast and axillary ultrasound, ultrasound-guided core needle biopsy/fine needle aspiration (FNA) and breast surgery. Simultaneous with the training exercises, a new breast care clinic was established and operationalised, and existing surgical theatres were upgraded. All activities were implemented in a private sector health care facility - Biamba Marie Mutombo Hospital - in the capital city of Kinshasa.

Results

From April 2017 to August 2020, a total of 5,211 women were identified as having breast abnormalities on CBE. Ages ranged from 26 to 86 years; median age: 42.0 (±14.1) years. Ultrasound abnormalities were noted in 1,420 (27%) clients, of which 516 (36%) met the criteria (indeterminate cystic lesion, solid or suspicious masses) for ultrasound-guided core needle biopsy or FNA. Pathology reports were available for 368 (71%) of the 516 clients who underwent biopsy, of which 164 were malignant and 204 benign. The majority (88%) of the cancers were advanced (TNM stages 3 and 4). Surgical procedures consisted of 183 lumpectomies, 58 modified radical mastectomies and 45 axillary lymph node dissections. Clinical competency for diagnostic and surgical procedures was reached early in the course of the training programme.

Conclusion

By integrating onsite training with simultaneous investments in clinical service and infrastructure development, the barriers to breast cancer diagnosis and treatment were disrupted and a modern breast care service platform was established in a private sector health care facility in the DRC.

Molecular markers, pathology, and ultrasound features of invasive breast cancer

INTRODUCTION

Ultrasound is commonly used in breast cancer screening and diagnosis. The use of ultrasound features to predict the subtypes of invasive breast cancer is of great clinical significance, since it facilitates a fast and early diagnosis and treatment. The correlation between breast lesion ultrasound features and the breast cancer subtypes requires further investigation.

METHODS

388 patients with invasive breast cancer were retrospectively analyzed by two sonographers. The tumor size, shape, margin, echogenicity, echotexture, posterior echo attenuation microcalcification, and blood vessel density were recorded. The correlation between the tumor ER, PR, HER2, and Ki67 status, the molecular subtypes, and the ultrasound features was analyzed using the chi-square test, Fisher's exact test, and multiple logistic regression.

RESULTS

ER and PR positivity were correlated with a low histologic grade, lymph node metastasis, and smaller-sized tumors. A hyperechoic or a mixed echogenicity was rare in the tumors of all groups but was enriched in the ER and PR tumors (9.57% and 7.64%, respectively, p < 0.01). A high percentage of posterior echo attenuation was found in the Ki67 low (53.94%) and ER+ (51.28%) tumors. Furthermore, heterogeneous and microcalcifications were enriched in HER2-positive tumors. In terms of the molecular subtypes, the luminal A subtype group had the lowest lymph node positivity and the smallest primary tumor size. The luminal B subtype had the lowest percentage of hyperechoic or mixed tumors. The HER2 subtype was positively correlated with microcalcification. Finally, TNBC showed the highest percentage of hyperechoic or mixed tumors and the lowest percentage of posterior echo attenuation and microcalcification.

CONCLUSION

Tumor pathologic and ultrasound features were correlated with invasive breast tumor molecular marker positivity and its molecular subtypes.

Comparative analysis of triple-negative breast cancer transcriptomics of Kenyan, African American and Caucasian Women

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The current study determined the molecular fingerprints of TNBCs of women from kenya (KE) and compared them with those of African–American (AA) and Caucasian (CA) women.

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RNA sequencing analysis highlights the role of molecular alterations in TNBCs and the potential benefit of targeting pathways in this disease for the KE population as compared to AAs and CAs.

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The dysregulated genes and signaling pathways could contributes to the aggressive phenotypes of TNBCs of KE women.

Purpose

: Triple-negative breast cancer (TNBC) patients of various ethnic groups often have discrete clinical presentations and outcomes. Women of African descent have a disproportionately higher chance of developing TNBCs. The aim of the current study was to establish the transcriptome of TNBCs from Kenyan (KE) women of Bantu origin and compare it to those TNBCs of African-Americans (AA) and Caucasians (CA) for identifying KE TNBC-specific molecular determinants of cancer progression and potential biomarkers of clinical outcomes.

Patients and Methods

: Pathology-confirmed TNBC tissues from Kenyan women of Bantu origin (n = 15) and age and stage range matched AA (n = 19) and CA (n = 23) TNBCs of patients from Alabama were included in this study. RNA was isolated from paraffin-embedded tissues, and expression was analyzed by RNA sequencing.

Results

: At clinical presentation, young KE TNBC patients have tumors of higher stages. Differential expression analysis identified 160 up-regulated and 178 down-regulated genes in KE TNBCs compared to AA and CA TNBCs. Validation analyses of the TCGA breast cancer data identified 45 KE TNBC-specific genes that are involved in the apoptosis (ACTC1, ERCC6 and CD14), cell proliferation (UHRF2, KDM4C, UHMK1, KCNH5, KRT18, CSF1R and S100A13), and Wnt signaling (BCL9L) pathways.

Conclusions

: In this study, we identified biomarkers that are specific for KE TNBC patients of Bantu origin. Further study with a larger sample size of matched tumors could confirm our findings. If biologically confirmed, these molecular determinants could have clinical and biological implications and serve as targets for development of personalized therapeutics for KE TNBC patients.

An overview of cancer health disparities: new approaches and insights and why they matter

Cancer health disparities remain stubbornly entrenched in the US health care system. The Affordable Care Act was legislation to target these disparities in health outcomes. Expanded access to health care, reduction in tobacco use, uptake of other preventive measures and cancer screening, and improved cancer therapies greatly reduced cancer mortality among women and men and underserved communities in this country. Yet, disparities in cancer outcomes remain. Underserved populations continue to experience an excessive cancer burden. This burden is largely explained by health care disparities, lifestyle factors, cultural barriers, and disparate exposures to carcinogens and pathogens, as exemplified by the COVID-19 epidemic. However, research also shows that comorbidities, social stress, ancestral and immunobiological factors, and the microbiome, may contribute to health disparities in cancer risk and survival. Recent studies revealed that comorbid conditions can induce an adverse tumor biology, leading to a more aggressive disease and decreased patient survival. In this review, we will discuss unanswered questions and new opportunities in cancer health disparity research related to comorbid chronic diseases, stress signaling, the immune response, and the microbiome, and what contribution these factors may have as causes of cancer health disparities.

Ancestry-associated transcriptomic profiles of breast cancer in patients of African, Arab, and European ancestry

Breast cancer largely dominates the global cancer burden statistics; however, there are striking disparities in mortality rates across countries. While socioeconomic factors contribute to population-based differences in mortality, they do not fully explain disparity among women of African ancestry (AA) and Arab ancestry (ArA) compared to women of European ancestry (EA). In this study, we sought to identify molecular differences that could provide insight into the biology of ancestry-associated disparities in clinical outcomes. We applied a unique approach that combines the use of curated survival data from The Cancer Genome Atlas (TCGA) Pan-Cancer clinical data resource, improved single-nucleotide polymorphism-based inferred ancestry assignment, and a novel breast cancer subtype classification to interrogate the TCGA and a local Arab breast cancer dataset. We observed an enrichment of BasalMyo tumors in AA patients (38 vs 16.5% in EA, p = 1.30E - 10), associated with a significant worse overall (hazard ratio (HR) = 2.39, p = 0.02) and disease-specific survival (HR = 2.57, p = 0.03). Gene set enrichment analysis of BasalMyo AA and EA samples revealed differences in the abundance of T-regulatory and T-helper type 2 cells, and enrichment of cancer-related pathways with prognostic implications (AA: PI3K-Akt-mTOR and ErbB signaling; EA: EGF, estrogen-dependent and DNA repair signaling). Strikingly, AMPK signaling was associated with opposing prognostic connotation (AA: 10-year HR = 2.79, EA: 10-year HR = 0.34). Analysis of ArA patients suggests enrichment of BasalMyo tumors with a trend for differential enrichment of T-regulatory cells and AMPK signaling. Together, our findings suggest that the disparity in the clinical outcome of AA breast cancer patients is likely related to differences in cancer-related and microenvironmental features.

Epidemiology of Triple-Negative Breast Cancer: A Review

ABSTRACT

Triple-negative breast cancer accounted for 12% of breast cancers diagnosed in the United States from 2012 to 2016, with a 5-year survival 8% to 16% lower than hormone receptor-positive disease. However, preventive and screening strategies remain tailored to the demographics of less lethal luminal cancers. This review examines the ethnic, genetic, and modifiable risk factors associated with triple-negative breast cancer, which providers must recognize to address the societal disparities of this deadly disease. Most notable is that triple-negative cancers disproportionately affect African American women and carriers of germline BRCA and PALB2 mutations. Even controlling for treatment delays, stage, and socioeconomic factors, African Americans with triple-negative breast cancer remain nearly twice as likely to die of their disease. To level the playing field, we must integrate genomic predictors of disease and epidemiologic characteristics of molecular breast cancer subtypes to provide personalized risk assessment, screening, and treatment for each patient.