Comparative Analysis of Breast Cancer Phenotypes in African American, White American, and West Versus East African patients: Correlation Between African Ancestry and Triple-Negative Breast Cancer

The DARC side of genetics in cancer: Breast cancer disparities

Highlighting the Distinguished Speakers Symposium on "The Future of Human Genetics and Genomics," this collection of articles is based on presentations at the ASHG 2023 Annual Meeting in Washington, DC, in celebration of all our field has accomplished in the past 75 years, since the founding of ASHG in 1948.

Genetic ancestry is related to potential sources of breast cancer health disparities among Colombian women

Breast cancer health disparities are linked to clinical-pathological determinants, socioeconomic inequities, and biological factors such as genetic ancestry. These factors collectively interact in complex ways, influencing disease behavior, especially among highly admixed populations like Colombians. In this study, we assessed contributing factors to breast cancer health disparities according to genetic ancestry in Colombian patients from a national cancer reference center. We collected non-tumoral paraffin embedded (FFPE) blocks from 361 women diagnosed with breast cancer at the National Cancer Institute (NCI) to estimate genetic ancestry using a 106-ancestry informative marker (AIM) panel. Differences in European, Indigenous American (IA) and African ancestry fractions were analyzed according to potential sources of breast cancer health disparities, like etiology, tumor-biology, treatment administration, and socioeconomic-related factors using a Kruskal-Wallis test. Our analysis revealed a significantly higher IA ancestry among overweight patients with larger tumors and those covered by a subsidized health insurance. Conversely, we found a significantly higher European ancestry among patients with smaller tumors, residing in middle-income households, and affiliated to the contributory health regime, whereas a higher median of African ancestry was observed among patients with either a clinical, pathological, or stable response to neoadjuvant treatment. Altogether, our results suggest that the genetic legacy among Colombian patients, measured as genetic ancestry fractions, may be reflected in many of the clinical-pathological variables and socioeconomic factors that end up contributing to health disparities for this disease.

Neighborhood Disadvantage and Breast Cancer-Specific Survival in the US

Importance

Despite improvements in breast cancer screening, treatment, and survival, disparate breast cancer-specific survival outcomes persist, particularly in disadvantaged neighborhoods. Most of these disparities are attributed to disparities in individual, tumor, and treatment characteristics. However, a critical knowledge gap exists as to whether disparities in breast cancer-specific survival remain after accounting for individual, tumor, and treatment characteristics.

Objective

To evaluate if neighborhood disadvantage is associated with shorter breast cancer-specific survival after controlling for individual, tumor, and treatment characteristics in a national population.

Design, Setting, and Participants

This national retrospective cohort study included patients with breast cancer diagnosed from 2013 to 2018 from the Surveillance, Epidemiology, and End Results 17 Census tract-level socioeconomic status and rurality database of the National Cancer Institute. Data analysis was performed from September 2022 to December 2023.

Exposures

Neighborhood disadvantage measured by Yost index quintiles.

Main Outcomes and Measures

Breast cancer-specific survival was evaluated using a competing risks cause-specific hazard model controlling for age, race, ethnicity, rurality, stage, subtype, insurance, and receipt of treatment.

Results

A total of 350 824 patients with breast cancer were included; 41 519 (11.8%) were Hispanic, 39 631 (11.3%) were non-Hispanic Black, and 234 698 (66.9%) were non-Hispanic White. A total of 87 635 patients (25.0%) lived in the most advantaged neighborhoods (group 5) and 52 439 (14.9%) lived in the most disadvantaged neighborhoods (group 1). A larger number of non-Hispanic White patients (66 529 patients [76.2%]) lived in advantaged neighborhoods, while disadvantaged neighborhoods had the highest proportion of non-Hispanic Black (16 141 patients [30.9%]) and Hispanic patients (10 168 patients [19.5%]). Breast cancer-specific survival analysis found the most disadvantaged neighborhoods (group 1) had the highest risk of mortality (hazard ratio, 1.43; 95% CI, 1.36-1.50; P < .001) compared with the most advantaged neighborhoods.

Conclusions and Relevance

In this national cohort study of patients with breast cancer, neighborhood disadvantage was independently associated with shorter breast cancer-specific survival even after controlling for individual-level factors, tumor characteristics, and treatment. This suggests potential unaccounted-for mechanisms, including both nonbiologic factors and biologic factors.

Comparative analysis of breast cancer characteristics in young premenopausal and postmenopausal women in Ghana

Breast cancer is increasingly common among young women in Ghana. BCa is heterogeneous with unique traits that impact causes, prognostic, and predictive outcomes of patients before and after menopause. However, limited evidence exists on differences between young premenopausal (YPM) and postmenopausal cases in Ghana. This study compared breast tumour characteristics between YPM women (under 35 years) and postmenopausal women. We conducted a prospective cross-sectional study involving 140 BCa-diagnosed women at the Breast Care Clinic of Komfo Anokye Teaching Hospital (KATH), Kumasi from November 2019 to June 2021. Thirty-one (22.1%) of participants were YPM and 109 (77.9%) were postmenopausal. The median ages for YPM and postmenopausal were 32.0 (range: 25.0-35.0) and 57.0 (48.0-86.0) respectively. Invasive carcinoma was the most common histological type (97.1%). Left tumour location was the most frequent in both groups (51.6% for YPM and 51.8% for postmenopausal). Lumps detected were frequently in the outer upper quadrant in both groups (61.3% and 56.0%). The majority of the YPM women (80.7%) and postmenopausal women (87.0%) had stage III and IV diseases. Most YPM (64.5%) and postmenopausal women (64.4%) exhibited triple-negative breast cancer (TNBC). Both YPM 13 (56.6%) and postmenopausal participants 40 (56.3%) exhibited a predominantly partial response to neo-adjuvant chemotherapy but YPM women (21.7%) experienced disease progression than the postmenopausal women (12.7%). The study highlights consistent tumour characteristics and advanced clinical stages at diagnosis in both groups with a higher prevalence of TNBC. TNBC and HER2+ subtypes respond better to Anthracycline-based neoadjuvant chemotherapy. Establishing Breast Care Clinics in district and regional hospitals for early detection is crucial and further studies are warranted to understand the higher TNBC prevalence in black Africans and re-evaluate breast education programs to address the persistently late presentations.

Tumor sequencing of African ancestry reveals differences in clinically relevant alterations across common cancers

Cancer genomes from patients with African (AFR) ancestry have been poorly studied in clinical research. We leverage two large genomic cohorts to investigate the relationship between genomic alterations and AFR ancestry in six common cancers. Cross-cancer type associations, such as an enrichment of MYC amplification with AFR ancestry in lung, breast, and prostate cancers, and depletion of BRAF alterations are observed in colorectal and pancreatic cancers. There are differences in actionable alterations, such as depletion of KRAS G12C and EGFR L858R, and enrichment of ROS1 fusion with AFR ancestry in lung cancers. Interestingly, in lung cancer, KRAS mutations are less common in both smokers and non-smokers with AFR ancestry, whereas the association of TP53 mutations with AFR ancestry is only seen in smokers, suggesting an ancestry-environment interaction that modifies driver rates. Our study highlights the need to increase representation of patients with AFR ancestry in drug development and biomarker discovery.

Translational Epidemiology: Genetic Ancestry in Breast Cancer: What Is the Role of Genetic Ancestry and Socioeconomic Status in Triple-Negative Breast Cancer?

Racial/ethnic and socioeconomic disparities seen in triple-negative breast cancer (TNBC) have prompted questions regarding the role of genetic ancestry in breast cancer (BC) subtype development, tumor biology, and ultimately prognosis. The causes of disparities in TNBC are influenced greatly by both sociopolitical factors and genetic ancestry, and now, the potential genomic underpinnings of social factors. To comprehensively understand disparities in TNBC, it is critical to take a translational epidemiologic approach that takes into account genomic and non-genomic factors. Understanding the interplay between genetic ancestry and social genomics and their proportional influence on outcomes can guide our priorities for screening, diagnosis, and interventions for this aggressive BC subtype.

Breast Cancer Phenotypes in Africa: A Scoping Review and Meta-Analysis

PURPOSE

Africans have been associated with more aggressive forms of breast cancer (BC). However, there is a lack of data regarding the incidence and distribution of different subtypes on the basis of phenotypic classification. This scoping review and meta-analysis was undertaken to determine the distribution pattern of BC phenotypes (luminal, human epidermal growth factor receptor 2 [HER2]+, and triple-negative breast cancer [TNBC]) across the African region.

METHODS

Four online databases (PubMed, Scopus, ProQuest, and EBSCOhost) were accessed to identify studies published between 2000 and 2022 reporting the representation of receptor status (estrogen receptor, progesterone receptor, and HER2) in African patients with BC. Furthermore, the meta-analysis was carried out using a random-effects model and pooled using the inverse variance method and logit transformation. 95% CI and I2 statistics were calculated using the Clopper-Pearson method to estimate between-study heterogeneity.

RESULTS

A total of 2,734 records were retrieved, of which 2,133 were retained for further screening. After the screening, 63 studies were finally selected for the scoping review and meta-analysis. The pooled frequency of luminal, HER2-positive (HER2+), and TNBC was estimated at 56.30%, 12.61%, and 28.10%, respectively. Northern Africa had the highest frequency of the luminal subtype, while West Africa showed higher frequencies of HER2+ and TNBC subtypes. The review also had a representation of only 24 countries in Africa.

CONCLUSION

Our results highlight the disparity in the representation of molecular subtypes among the people in different regions of Africa. There is a need to incorporate routine molecular subtyping into the management of African patients with BC.

Circulating natural killer cells and their association with breast cancer and its clinico-pathological characteristics

Purpose

Natural killer (NK) cells play a critical role in cancer immunosurveillance and hold promise as both therapies and prognostic markers in advanced disease. We explore factors that may influence NK cell concentration in the peripheral blood of women with breast cancer in Côte d'Ivoire compared to healthy controls and implications for future research in our context.

Methods

In this cross-sectional case-control study, blood samples were taken from 30 women diagnosed with breast cancer within 6 months of diagnosis and fifteen healthy women at University Teaching Hospital [Centre Hospitalier Universitaire (CHU)] Treichville in Abidjan, Côte d'Ivoire, from March to September 2018. The blood draw could take place at any time following diagnosis and through treatment. Demographic and clinical data were collected. NK cells were isolated, stained, analysed and counted using the flow cytometer at the Department of Immunology at CHU of Cocody. All p-values were two-sided.

Results

Mean age among 30 women with breast cancer was 49 years old compared to 45 years old for 15 controls (p = 0.41). Among 30 women with breast cancer, 4 (13.3%) had Stage 2 disease, 14 (46.7 %) at Stage 3, and 12 (40%) at Stage 4. Fourteen (46.7%) had breast cancer that was hormone receptor-positive (HR+) HER2-negative, 10 (33.3%) had triple-negative cancer, three (10.0%) had HR+HER2+ disease, and three (10.0%) HR-HER2+ cancer. NK cell concentration was not associated with cancer diagnosis, age, cancer stage, subtype, or type of treatment patients received (p > 0.05).

Conclusion

Although we did not find an association between NK cell concentration, cancer characteristics or treatment, our results be limited by the small sample size and timing of blood draw. Our next steps include a larger study to explore circulating NK cells prior to any treatment and NK cell infiltration within breast cancer tumour and correlating this with response to treatment and prognosis.

Immunohistochemistry versus PCR Technology for Molecular Subtyping of Breast Cancer: Multicentered Expereinces from Addis Ababa, Ethiopia

The application of immunohistochemistry (IHC) for molecular characterization of breast cancer (BC) is of paramount importance; however, it is not universally standardized, subject to observer variability and quantifying is a challenge. An alternative molecular technology, such as endpoint reverse transcription (RT)-PCR gene expression analysis, may improve observer variability and diagnostic accuracy. This study was intended to compare IHC with the RT-PCR based technique and assess the potential of RT-PCR for molecular subtyping of BC. In this comparative cross-sectional study, 54 BC tissues were collected from three public hospitals in Addis Ababa and shipped to Gynaecology department at Martin-Luther University (Germany) for laboratory analysis. Only 41 samples were qualified for IHC and RT-PCR investigation of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 protein expression analysis. Kappa statistics was used to assess the concordance between the two techniques. The overall percent agreement between RT-PCR and IHC was 68.3% for ER (positive percent agreement [PPA] 71.1%; negative percent agreement [NPA] 33.3%), 39.0% for PR (PPA 14.3%; NPA 92.3%), and 82.9% for HER2 (PPA 62.5%; NPA 87.9%). Cohen's κ-values of 0.018 (< 0.20), 0.045 (< 0.200), and 0.481 (0.41-0.60) were generated for ER, PR, and HER2, respectively. Concordance for molecular subtypes was only 56.1% (23/41) and 0.20 kappa value. IHC and endpoint RT-PCR techniques have shown to be discordant for 43% samples. Molecular subtyping using endpoint RT-PCR was fairly concordant with IHC. Thus, endpoint RT-PCR may give an objective result, and can be applied for BC subtyping.

Luminal B, Human Epidermal Growth Factor Receptor 2 (HER2/neu), and Triple-Negative Breast Cancers Associated With a Better Chemotherapy Response Than Luminal A Breast Cancers in Postneoadjuvant Settings

Background Breast cancer is a heterogeneous disease with many histological and molecular/intrinsic breast cancer subtypes. Intrinsic breast cancer subtypes include luminal A, luminal B, human epidermal growth factor receptor 2 (HER2/neu), and triple-negative subtypes. The intrinsic breast cancer typing is based on the expression of estrogen receptor (ER), progesterone receptor (PR), HER2/neu, and Ki67-labeling index. One of these patients' foremost prognostic factors upon surgical resection is a response to neoadjuvant chemotherapy. The presence of a pathologically complete response (pCR) indicates a favorable patient outcome compared with a pathologically partial response (pPR). In this study, we compared the neoadjuvant chemotherapy response in breast cancer in different intrinsic breast cancer subtypes. Methodology It was a retrospective cross-sectional study conducted in the Department of Histopathology, Liaquat National Hospital, from January 2019 to December 2022, over three years. A total of 287 post-neoadjuvant chemotherapy cases of breast cancer were included. Anthracyclines and taxanes, coupled with or without anti-HER2/neu therapy, have been used in the neoadjuvant chemotherapy treatment setting contingent upon the patients' HER2/neu status. The post-chemotherapy response was assessed pathologically and categorized into pCR and pPR. Results The mean age of the patients was 47.90 ± 10.34 years, with a mean tumor size and Ki67 index of 5.36 ± 2.59 cm and 36.30 ± 22.14%, respectively. Invasive breast carcinoma of no special type (IBC-NST) made up 88.2% of cases, while grade 2 carcinomas made up 45.5%. The majority of tumors (42.7%) belonged to tumor (T) stage T2, and nodal metastasis was detected in 59.7% of patients. The intrinsic breast cancer subtypes luminal B (40.6%) and triple negative (33.3%) were the most prevalent, followed by luminal A (15.8%) and HER2/neu (10.3%). In 81 cases (24.5%), pCR was detected. The association of post-neoadjuvant chemotherapy response with intrinsic breast cancer subtypes showed a significant difference (P < 0.001). The highest frequency of pCR was noted in HER2/neu cancers (58.8%), followed by luminal B (25.4%) and triple negative (23.6%). Regarding age, T-stage, tumor grade, and histological type of carcinoma, there was no discernible difference between pCR and pPR. Conversely, a significant association was noted for the Ki67 index. A Ki67 index higher than 25% showed a significantly higher frequency of pCR. Conclusions In postchemotherapy specimens, the HER2/neu breast cancer subtype substantially displayed higher pCR, followed by luminal B and triple-negative subtypes. After identifying the patients' subtypes, intrinsic subtyping can help determine the prognosis and anticipated response to chemotherapy. Furthermore, prechemotherapy breast specimens with high Ki67 index values have shown a direct association with neoadjuvant chemotherapy response.

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.

The Landmark Series-Addressing Disparities in Breast Cancer Screening: New Recommendations for Black Women

Randomized, clinical trials have established the efficacy of screening mammography in improving survival from breast cancer for women through detection of early, asymptomatic disease. However, disparities in survival rates between black women and women from other racial and ethnic groups following breast cancer diagnosis persist. Various professional groups have different, somewhat conflicting, guidelines with regards to recommended age for commencing screening as well as recommended frequency of screening exams, but the trials upon which these recommendations are based were not specifically designed to examine benefit among black women. Furthermore, these recommendations do not appear to incorporate the unique epidemiological circumstances of breast cancer among black women, including higher rates of diagnosis before age 40 years and greater likelihood of advanced stage at diagnosis, into their formulation. In this review, we examined the epidemiologic and socioeconomic factors that are associated with breast cancer among black women and assess the implications of these factors for screening in this population. Specifically, we recommend that by no later than age 25 years, all black women should undergo baseline assessment for future risk of breast cancer utilizing a model that incorporates race (e.g., Breast Cancer Risk Assessment Tool [BCRAT], formerly the Gail model) and that this assessment should be conducted by a breast specialist or a healthcare provider (e.g., primary care physician or gynecologist) who is trained to assess breast cancer risk and is aware of the increased risks of early (i.e., premenopausal) and biologically aggressive (e.g., late-stage, triple-negative) breast cancer among black women.

Racial Disparities in Clinical Outcomes on Investigator-Initiated Breast Cancer Clinical Trials at an Urban Medical Center

BACKGROUND

Black women are 40% more likely to die of breast cancer compared to White women. Inadequate representation of Black patients in clinical trials may contribute to health care inequity. We aimed to assess breast cancer clinical outcomes in Non-Hispanic Black (Black) versus Non-Hispanic White (White) women with metastatic breast cancer (MBC) enrolled on investigator-initiated clinical trials at Winship Cancer Institute at Emory University, given the significant number of patients from underrepresented minority groups seen at Winship.

MATERIALS AND METHODS

Black and White women with MBC on investigator-initiated trials at Emory between 2009 and 2019 were retrospectively evaluated. Univariate analyses and multiple logistic regression models were used to assess clinical response and treatment toxicities. Differences in overall survival between groups was assessed using quantile analysis.

RESULTS

Sixty-two women with MBC were included (66% White vs. 34% Black). Black patients had less clinical benefit from the trial therapy as only 57% had partial response or stable disease as best response compared to 78% of White women (P = .09). Quantile analysis showed significant difference in mean survival between Whites and Blacks by the end of follow up (64 vs. 38 months). There were no significant differences in toxicities between groups.

CONCLUSION

Participation rates of Black women with MBC on investigator-initiated clinical trials at an urban cancer center were higher compared to key national trials. Black women had worse treatment response and survival. These results reinforce the need for assessment of tumor differences by ancestry and continued improvement in minority representation on clinical trials.

African Ancestry-Associated Gene Expression Profiles in Triple-Negative Breast Cancer Underlie Altered Tumor Biology and Clinical Outcome in Women of African Descent

Women of sub-Saharan African descent have disproportionately higher incidence of triple-negative breast cancer (TNBC) and TNBC-specific mortality across all populations. Population studies show racial differences in TNBC biology, including higher prevalence of basal-like and quadruple-negative subtypes in African Americans (AA). However, previous investigations relied on self-reported race (SRR) of primarily U.S. populations. Due to heterogeneous genetic admixture and biological consequences of social determinants, the true association of African ancestry with TNBC biology is unclear. To address this, we conducted RNA sequencing on an international cohort of AAs, as well as West and East Africans with TNBC. Using comprehensive genetic ancestry estimation in this African-enriched cohort, we found expression of 613 genes associated with African ancestry and 2,000+ associated with regional African ancestry. A subset of African-associated genes also showed differences in normal breast tissue. Pathway enrichment and deconvolution of tumor cellular composition revealed that tumor-associated immunologic profiles are distinct in patients of African descent.

SIGNIFICANCE

Our comprehensive ancestry quantification process revealed that ancestry-associated gene expression profiles in TNBC include population-level distinctions in immunologic landscapes. These differences may explain some differences in race-group clinical outcomes. This study shows the first definitive link between African ancestry and the TNBC immunologic landscape, from an African-enriched international multiethnic cohort. See related commentary by Hamilton et al., p. 2496. This article is highlighted in the In This Issue feature, p. 2483.

Immune Lymphocyte Infiltrate and its Prognostic Value in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) occurs more frequently in young (<50 years) non-Hispanic black and Hispanic/Latina women. It is considered the most aggressive subtype of breast cancer, although, recently, immune infiltrate has been associated with long-term survival, lower risk of death and recurrence, and response to neoadjuvant chemotherapy. The aim of this review was to evaluate the clinical impact of the immune infiltrate in TNBC by discussing whether its prognostic value varies across different populations. A comprehensive systematic search in databases such as PubMed and Web of Science was conducted to include papers focused on tumor-infiltrating lymphocytes (TILs) in TNBC in different population groups and that were published before January 2021. TNBC patients with higher levels of TILs had longer overall survival and disease-free survival times compared with TNBC patients with low TIL levels. Similar results were observed for CD4+, CD8+ TIL populations. On the other hand, patients with high TIL levels showed a higher rate of pathological complete response regardless of the population group (Asian, European, and American). These results altogether suggest that TIL subpopulations might have a prognostic role in TNBC, but the underlying mechanism needs to be elucidated. Although the prognosis value of TILs was not found different between the population groups analyzed in the revised literature, further studies including underrepresented populations with different genetic ancestries are still necessary to conclude in this regard.

Association of lipid profile biomarkers with breast cancer by molecular subtype: analysis of the MEND study

There is conflicting evidence on the role of lipid biomarkers in breast cancer (BC), and no study to our knowledge has examined this association among African women. We estimated odds ratios (ORs) and 95% confidence intervals (95% CI) for the association of lipid biomarkers-total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides-with odds of BC overall and by subtype (Luminal A, Luminal B, HER2-enriched and triple-negative or TNBC) for 296 newly diagnosed BC cases and 116 healthy controls in Nigeria. Each unit standard deviation (SD) increase in triglycerides was associated with 39% increased odds of BC in fully adjusted models (aOR: 1.39; 95% CI: 1.03, 1.86). Among post-menopausal women, higher total cholesterol (aOR: 1.65; 95% CI: 1.06, 2.57), LDL cholesterol (aOR: 1.59; 95% CI: 1.04, 2.41), and triglycerides (aOR: 1.91; 95% CI: 1.21, 3.01) were associated with increased odds of BC. Additionally, each unit SD increase in LDL was associated with 64% increased odds of Luminal B BC (aOR 1.64; 95% CI: 1.06, 2.55). Clinically low HDL was associated with 2.7 times increased odds of TNBC (aOR 2.67; 95% CI: 1.10, 6.49). Among post-menopausal women, higher LDL cholesterol and triglycerides were significantly associated with increased odds of Luminal B BC and HER2 BC, respectively. In conclusion, low HDL and high LDL are associated with increased odds of TN and Luminal B BC, respectively, among African women. Future prospective studies can definitively characterize this association and inform clinical approaches targeting HDL as a BC prevention strategy.

Breast Cancer Survival in Eastern Region of Ghana

Objective

Five-year overall survival rate of breast cancer in low-income countries (LICs) is significantly lower than in high-resource countries. This study explored clinical and pathological factors influencing mortality in the Eastern region of Ghana.

Methods

We performed a retrospective medical chart review for patients undergoing surgery and chemotherapy for breast cancer at a regional hospital in Ghana from January 2014 to January 2017. Descriptive and survival analysis was done.

Results

One hundred and twenty-nine patients were included in the study. The median age at presentation was 51 years. Sixty percent of patients presented with poorly differential histological grade III. The most common histological type was invasive ductal carcinoma (83%). Based on stage assessment using only tumor size and lymph node status, 60% presented at stage 3. Only 25% were tested for hormone receptor proteins and HER2 status. Of these, 57% had triple-negative breast cancer (TNBC). The 3-year overall survival rate was only 52%.

Conclusion

The cumulative 3-year survival was 52%. Despite success in reducing cancer mortality in northern Africa, survival in sub-Saharan Africa remains poor. A significantly higher percentage of GIII and TNBC is found in breast cancers seen in Ghana. When combined with limited capacity for accurate diagnosis, cancer subtype analysis, adequate therapy, and follow-up, late-stage presentation leads to poor outcomes. Future studies should emphasize the identification of barriers to care and opportunities for cost-effective and sustainable improvements in diagnosing and treating breast cancer in LICs.

Analysis of pathogenic variants in BRCA1 and BRCA2 genes using next-generation sequencing in women with triple negative breast cancer from South India

BACKGROUND

The frequency of triple-negative breast cancer (TNBC) incidence varies among different populations suggesting the involvement of genetic components towards TNBC development. Previous studies have reported that BRCA1/2 germline mutations confer a lifetime risk of developing TNBC. However, there is hardly any information regarding the common pathogenic variants (PVs) in BRCA1/2 genes that contribute to TNBC in the Indian population. Hence, we screened for PVs in BRCA1/2 and their association with clinico-pathological features in TNBC patients.

METHODS AND RESULTS

The study recruited 59 TNBC patients without hereditary breast and ovarian cancer (HBOC) from South India. The entire BRCA1 and BRCA2 genes were sequenced for the 59 patients using the Illumina HiSeq X Ten sequencer. Among the 59 TNBC genomic DNA samples sequenced, BRCA mutations were identified in 8 patients (13.6%), BRCA1 mutations in 6 patients, and BRCA2 mutations in 2 patients. Among the 6 BRCA1 mutations, three were c.68_69delAG (185delAG) mutation. Remarkably, all the TNBC patients with BRCA mutations exhibited higher-grade tumors (grade 2 or 3). However, among all the BRCA mutation carriers, only one patient with a BRCA2 mutation (p.Glu1879Lys) developed metastasis.

CONCLUSION

Our data advocates that South Indian women with higher grade TNBC tumors and without HBOC could be considered for BRCA mutation screening, thereby enabling enhanced decision-making and preventive therapy.

Changing Trends in Estrogen Receptors/Progesterone Receptors/Human Epidermal Growth Factor Receptor 2 Prevalence Rates Among Jordanian Patients With Breast Cancer Over the Years

PURPOSE

Estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal growth factor receptor 2 (HER2) are the mainstay of breast cancer management, and their prevalence rates vary among different populations possibly related to ethnic/genetic and/or socioeconomic status. In a previous study conducted at the King Hussein Cancer Center (published 2006), Jordan ER/PR/HER2 rates for patients diagnosed in 2003-2004 were 50.8%/57.5%/17.5%, respectively. The aim of this study is to revisit the prevalence rates to see if they have changed over the years with changing socioeconomic status.

MATERIALS AND METHODS

We retrieved clinicopathologic data of all patients (1,185) diagnosed with breast cancer during 2018. The data included age, histologic type, grade, and ER/PR/HER2 status as determined by immunohistochemistry and/or fluorescence in situ hybridization for HER2.

RESULTS

The mean age of patients was 52 (median = 51, range = 25-92) years, and the majority (73.2%) had invasive carcinoma of no special type. ER/PR/HER2 were 77.0%/72.4%./23.8%, respectively. Triple-negative breast cancers were 10.1%. In comparison with previous results of 2006, the changes are statistically significant. Similar changes were seen in other Middle Eastern populations. The current rates are close to those of Western populations.

CONCLUSION

Rates of ER/PR/HER2 expression have significantly changed and are close to those of Western populations for ER/PR. We propose that such changes are secondary to the adoption of a westernized lifestyle and socioeconomic changes.

Clinicopathological characteristics of breast cancer patients from Northern Tanzania: common aspects of late stage presentation and triple negative breast cancer

Purpose

Breast cancer (BC) is the second most common cancer among Tanzanian women. Oestrogen (ER), progesterone and human epidermal growth factor receptor 2 play major roles in prognosis and treatment but data for Tanzania are sparse. This study aimed to determine these patterns and histological types, tumour grading and staging of BC patients in northern Tanzania for a better understanding of BC in the Sub-Saharan African (SSA) setting.

Methods

A cross-sectional study recorded newly diagnosed BC cases at Kilimanjaro Christian Medical Centre between October 2018 and March 2019. Receptor status, histological types and grade, clinical stage and socio-demographic were recorded and descriptive and bivariate analyses performed.

Results

116 patients were enrolled. Median age was 53 years, 71.6% were ≥45 years. The commonest molecular subtype was triple negative breast cancer (TNBC) (n = 33; 28.4%). One hundred and two (87.9%) patients had invasive ductal carcinoma (IDC), poorly differentiated tumours (60; 51.7%) and clinical stage III disease (62; 53.0%). ER negative tumours were associated with poorly differentiated histological grade (relative risk (RR): 1.34 (0.87–2.07)), tumour size > 5 cm (RR: 1.67 (0.33–8.35)) and IDC (RR: 3.35 (0.56–20.23)). Clinical stages III & IV (odds ratio (OR): 1.64 (0.63–4.24)) were associated with hormone receptor (HR) negative tumours and metastasis (OR: 1.60 (0.68–3.74)) with TNBC. 18% of the patients reported about first-degree relatives with BC.

Conclusions

Most patients presented in advanced stages and TNBC in their menopause. HR negative tumours were associated with poor histological differentiation and IDC. The high percentage of positive family history of BC and the differences in receptor patterns compared to other parts of the world should urge further genetic research on BC in SSA.

Competitive Endogenous Role of the LINC00511/miR-185-3p Axis and miR-301a-3p From Liquid Biopsy as Molecular Markers for Breast Cancer Diagnosis

Breast cancer (BC) is the leading cause of female cancer-related mortalities. Evidence has illustrated the role of long non-coding RNAs (lncRNA) and microRNAs (miRNA) as promising pool of protein non-coding regulators, for tuning the aggressiveness of several malignancies. This research aims to unravel the expression pattern and the emphases of the diagnostic value of the long intergenic ncRNA00511 (LINC00511) and its downstream microRNA (miR-185-3p) and the pathogenic significance of the onco-miR-301a-3p in naïve BC patients. LINC00511 was chosen and validated, and its molecular binding was confirmed using bioinformatics. LINC00511 was measured in 25 controls and 70 patients using qPCR. The association between the investigated ncRNA’s expression and the BC patients’ clinicopathological features was assessed. Receiver operating characteristic (ROC) curve was blotted to weigh out their diagnostic efficacy over the classical tumor markers (TMs). Bioinformatics and Spearman correlation were used to predict the interaction between LINC00511, miR-185-3p, and miR-301a-3p altogether to patients’ features. LINC00511 and miR-301a-3p, in BC patients’ blood, were overexpressed, and their median levels increased significantly, while miR-185-3p was, in contrast, downregulated, being decreased fourfold. LINC00511 was elevated in BC early stages, when compared to late stages (p < 0.0003). LINC00511, miR-185-3p, and miR-301a-3p showed AUC superior to classical TMs, allowing us to conclude that the investigated ncRNAs, in BC patients’ liquid biopsy, are novel diagnostic molecular biomarker signatures. Lymph node metastasis (LNM) and advanced tumor grade were directly correlated with LINC00511 significantly. Additionally, both LINC00511 and miR-301a-3p were positively correlated with the aggressiveness of BC, as manifested in patients with larger tumors (>2 cm) at (p < 0.001). Therefore, these findings aid our understanding of BC pathogenesis, in the clinical setting, being related in part to the LINC00511/miR axis, which could be a future potential therapeutic target.

Genetic Mutations Associated with Hormone-Positive Breast Cancer in a Small Cohort of Ethiopian Women

In Ethiopia, a breast cancer diagnosis is associated with a prognosis significantly worse than that of Europe and the US. Further, patients presenting with breast cancer in Ethiopia are far younger, on average, and patients are typically diagnosed at very late stages, relative to breast cancer patients of European descent. Emerging data suggest that a large proportion of Ethiopian patients have hormone-positive (ER⁺) breast cancer. This is surprising given (1) that patients have late-stage breast cancer at the time of diagnosis, (2) that African Americans with breast cancer frequently have triple negative breast cancer (TNBC), and (3) these patients typically receive chemotherapy, not hormone-targeting drugs. To further examine the similarity of Ethiopian breast tumors to those of African Americans or of those of European descent, we sequenced matched tumor and normal adjacent tissue from Ethiopian patients from a small pilot collection. We identified mutations in 615 genes across all three patients, unique to the tumor tissue. Across this analysis, we found far more mutations shared between Ethiopian patient tissue and that from white patients (103) than we did comparing to African Americans (3). Several mutations were found in extracellular matrix encoding genes with known roles in tumor cell growth and metastasis. We suggest future mechanistic studies on this disease focus on these genes first, toward finding new treatment strategies for breast cancer patients in Ethiopia.

Opportunities for Improvement in the Administration of Neoadjuvant Chemotherapy for T4 Breast Cancer: A Comparison of the U.S. and Nigeria

BACKGROUND

Neoadjuvant chemotherapy (NAC) is an integral component of T4 breast cancer (BCa) treatment. We compared response to NAC for T4 BCa in the U.S. and Nigeria to direct future interventions.

MATERIALS AND METHODS

Cross-sectional retrospective analysis included all patients with non-metastatic T4 BCa treated from 2010 to 2016 at Memorial Sloan Kettering Cancer Center (New York, New York) and Obafemi Awolowo University Teaching Hospitals Complex (Ile Ife, Nigeria). Pathologic complete response (pCR) and survival were compared and factors contributing to disparities evaluated.

RESULTS

Three hundred and eight patients met inclusion criteria: 157 (51%) in the U.S. and 151 (49%) in Nigeria. All U.S. patients received NAC and surgery compared with 93 (62%) Nigerian patients. Fifty-six out of ninety-three (60%) Nigerian patients completed their prescribed course of NAC. In Nigeria, older age and higher socioeconomic status were associated with treatment receipt. Fewer patients in Nigeria had immunohistochemistry performed (100% U.S. vs. 18% Nigeria). Of those with available receptor subtype, 18% (28/157) of U.S. patients were triple negative versus 39% (9/23) of Nigerian patients. Overall pCR was seen in 27% (42/155) of U.S. patients and 5% (4/76) of Nigerian patients. Five-year survival was significantly shorter in Nigeria versus the U.S. (61% vs. 72%). However, among the subset of patients who received multimodality therapy, including NAC and surgery with curative intent, 5-year survival (67% vs. 72%) and 5-year recurrence-free survival (48% vs. 61%) did not significantly differ between countries.

CONCLUSION

Addressing health system, socioeconomic, and psychosocial barriers is necessary for administration of complete NAC to improve BCa outcomes in Nigeria.

IMPLICATIONS FOR PRACTICE

This cross-sectional retrospective analysis of patients with T4 breast cancer in Nigeria and the U.S. found a significant difference in pathologic complete response to neoadjuvant chemotherapy (5% Nigeria vs. 27% U.S.). Five-year survival was shorter in Nigeria, but in patients receiving multimodality treatment, including neoadjuvant chemotherapy and surgery with curative intent, 5-year overall and recurrence-free survival did not differ between countries. Capacity-building efforts in Nigeria should focus on access to pathology services to direct systemic therapy and promoting receipt of complete chemotherapy to improve outcomes.

Cancer microenvironment and genomics: evolution in process

Cancer heterogeneity is a result of genetic mutations within the cancer cells. Their proliferation is not only driven by autocrine functions but also under the influence of cancer microenvironment, which consists of normal stromal cells such as infiltrating immune cells, cancer-associated fibroblasts, endothelial cells, pericytes, vascular and lymphatic channels. The relationship between cancer cells and cancer microenvironment is a critical one and we are just on the verge to understand it on a molecular level. Cancer microenvironment may serve as a selective force to modulate cancer cells to allow them to evolve into more aggressive clones with ability to invade the lymphatic or vascular channels to spread to regional lymph nodes and distant sites. It is important to understand these steps of cancer evolution within the cancer microenvironment towards invasion so that therapeutic strategies can be developed to control or stop these processes.

Breast cancer disparities in outcomes; unmasking biological determinants associated with racial and genetic diversity

Breast cancer (BC) remains a leading cause of death among women today, and mortality among African American women in the US remains 40% higher than that of their White counterparts, despite reporting a similar incidence of disease over recent years. Previous meta-analyses and studies of BC mortality highlight that tumor characteristics, rather than socio-economic factors, drive excess mortality among African American women with BC. This is further complicated by the heterogeneity of BC, where BC can more appropriately be defined as a collection of diseases rather than a single disease. Molecular phenotyping and gene expression profiling distinguish subtypes of BC, and these subtypes have distinct prognostic outcomes. Racial disparities transcend these subtype-specific outcomes, where African American women suffer higher mortality rates among all BC subtypes. The most striking differences are observed among the most aggressive molecular subtype, triple-negative BC (TNBC), where incidence and mortality are significantly higher among African American women compared to all other race/ethnicity groups. We and others have shown that this predisposition for triple-negative disease may be linked to shared west African ancestry, where the highest rates of TNBC are observed among west African nations, and these high frequencies follow into the African diaspora. Genetic and molecular characterization of breast tumors among subtypes and racial/ethnic groups have begun to identify targets with future therapeutic potential, but more work needs to be done to identify targeted treatment options for all women who suffer from BC.

Investigation of triple-negative breast cancer risk alleles in an International African-enriched cohort

Large-scale efforts to identify breast cancer (BC) risk alleles have historically taken place among women of European ancestry. Recently, there are new efforts to verify if these alleles increase risk in African American (AA) women as well. We investigated the effect of previously reported AA breast cancer and triple-negative breast cancer (TNBC) risk alleles in our African-enriched International Center for the Study of Breast Cancer Subtypes (ICSBCS) cohort. Using case-control, case-series and race-nested approaches, we report that the Duffy-null allele (rs2814778) is associated with TNBC risk (OR = 3.814, p = 0.001), specifically among AA individuals, after adjusting for self-indicated race and west African ancestry (OR = 3.368, p = 0.007). We have also validated the protective effect of the minor allele of the ANKLE1 missense variant rs2363956 among AA for TNBC (OR = 0.420, p = 0.005). Our results suggest that an ancestry-specific Duffy-null allele and differential prevalence of a polymorphic gene variant of ANKLE1 may play a role in TNBC breast cancer outcomes. These findings present opportunities for therapeutic potential and future studies to address race-specific differences in TNBC risk and disease outcome.

Differences in Breast Cancer Presentation at Time of Diagnosis for Black and White Women in High Resource Settings

This paper provides a narrative review of the existing literature on differences in demographic and biological features of breast cancer at time of diagnosis between Black and White women in Canada, the United Kingdom and the United States. Electronic database searches for published peer-reviewed articles on this topic were conducted, and 78 articles were included in the final narrative review. Differences between Black and White women were compared for eight categories including age, tumour stage, size, grade, lymph node involvement, and hormone status. Black women were significantly more likely to present with less favourable tumour features at the time of diagnosis than White women. Significant differences were reported in age at diagnosis, tumour stage, size, grade and hormone status, particularly triple negative breast cancer. Limitations on the generalizability of the review findings are discussed, as well as the implications of these findings on future research, especially within the Canadian context.

Receptor-Defined Breast Cancer in Five East African Countries and Its Implications for Treatment: Systematic Review and Meta-Analysis

PURPOSE

Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) are determinants of treatment and mortality for patients with breast cancer (BC). In East Africa, the estimated 5-year survival (37.7%) is far lower than the US average (90%). This meta-analysis investigates BC receptor subtypes within five East African countries to ascertain cross-country patterns and prioritize treatment needs.

METHODS

From a PubMed search, January 1, 1998-June 30, 2019, for all English-only BC articles for Ethiopia, Kenya, Rwanda, Tanzania, and Uganda, eligible studies had receptor distributions for female BC samples ≥ 30 patients. Outcomes were proportions of ER+, PR+, and HER2-positive (HER2+), and/or molecular subtypes. Data included study characteristics and mean or median patient age. Using metaprop, Stata 16, we estimated pooled proportions (ES) with 95% CIs and assessed heterogeneity.

RESULTS

Among 36 BC studies with receptor data, 21 met criteria. Weighted mean age was 47.5 years and median, 48. Overall ES were as follows: 55% for ER-positive (ER+) (95% CI, 47 to 62), 23% for HER2+ (95% CI, 20 to 26), and 27% for triple-negative BC (TNBC) (95% CI, 23 to 32).

CONCLUSION

We found differences between countries, for example, lower distribution of TNBC in Ethiopia (21%) compared with Uganda (35%). ER+, the dominant BC subtype overall at 55%, emphasizes the need to prioritize endocrine therapy. Overall proportions of HER2+ BC (with or without ER+ or PR+), 23%, approached proportions of TNBC, 27%, yet HER2 testing and treatment were infrequent. Testing and reporting of receptor subtypes would promote delivery of more effective treatment reducing the mortality disparity.

Multiethnic PDX models predict a possible immune signature associated with TNBC of African ancestry

PURPOSE

Triple-negative breast cancer (TNBC) is an aggressive subtype most prevalent among women of Western Sub-Saharan African ancestry. It accounts for 15-25% of African American (AA) breast cancers (BC) and up to 80% of Ghanaian breast cancers, thus contributing to outcome disparities in BC for black women. The aggressive biology of TNBC has been shown to be regulated partially by breast cancer stem cells (BCSC) which mediate tumor recurrence and metastasis and are more abundant in African breast tumors.

METHODS

We studied the biological differences between TNBC in women with African ancestry and those of Caucasian women by comparing the gene expression of the BCSC. From low-passage patient derived xenografts (PDX) from Ghanaian (GH), AA, and Caucasian American (CA) TNBCs, we sorted for and sequenced the stem cell populations and analyzed for differential gene enrichment.

RESULTS

In our cohort of TNBC tumors, we observed that the ALDH expressing stem cells display distinct ethnic specific gene expression patterns, with the largest difference existing between the GH and AA ALDH+ cells. Furthermore, the tumors from the women of African ancestry [GH/AA] had ALDH stem cell (SC) enrichment for expression of immune related genes and processes. Among the significantly upregulated genes were CD274 (PD-L1), CXCR9, CXCR10 and IFI27, which could serve as potential drug targets.

CONCLUSIONS

Further exploration of the role of immune regulated genes and biological processes in BCSC may offer insight into developing novel approaches to treating TNBC to help ameliorate survival disparities in women with African ancestry.

Adherence to endocrine therapy and its relation to disease-free survival among breast cancer patients visiting an out-patient clinic at Khartoum Oncology Hospital, Sudan

RATIONALE

Adherence to endocrine therapy provides substantial reduction in breast cancer (BC) relapses and improve survival. Hence, non-adherence remains an under reported issue mainly in developing countries.

AIMS AND OBJECTIVES

The aim of this study is to evaluate the adherence to endocrine therapy (tamoxifen [TAM] and aromatase inhibitors [AIs]) among BC patients visiting an out-patient clinic (2015-2016) in Khartoum Oncology Hospital, Sudan.

METHODS

Adherence was assessed using pills count and self-reporting methods. A total of 172 patients were interviewed. Also, records were reviewed for demographic and other cancer characteristics.

RESULTS

The patients' mean age at diagnosis was 53 years, with the highest frequency at (41-60) years. Invasive ductal carcinoma 69.2% formed the main pathological diagnosis. T2 tumour size (51.2%) and lymph node involvement (N1) (31.4%) were most evident. Also, the majority of patients were stage III (45.9%) and grade II (48%). The studied women were postmenopausal (49.4%) and premenopausal (47.7%). Regarding hormonal receptors, about 68% were oestrogen (ER)+/progesterone (PR)+ and 23.3% were ER+/PR-. Studying adherence, almost (93%) of the studied group were ≥80% adherent to TAM and AIs. The hormonal therapy persistence mean was 27.2 ± 22.5 months (40-96). While adherence percentage mean was 93.7 ± 13.6% (0%-100%). Also disease-free survival (DFS) mean was 36.3 ± 32.7 months (4-312). Adherence to hormonal therapy and persistence were significantly correlated (P < .000). Also, statistically significant association was found between hormonal therapy adherence (≥80%) and patient poor to average economic status (P = .006), and the marital status "married" (P = .008).

CONCLUSIONS

A high rate of adherence (93%) to endocrine therapy was estimated in the present study. Also, a positive association was found between the hormonal therapy persistence, and the DFS year's groups (P = .000), and the hormonal therapy types (P = .000). Adherence to hormonal therapy and persistence were significantly correlated (P < .000).

Breast cancer in togolese women: immunohistochemistry subtypes

Background

Molecular classification of breast cancer is an important factor for prognostic and clinical outcomes. There are no data regarding molecular breast cancer subtypes among Togolese women. The objective of this study was to evaluate the expression of ER, PR, HER2, and molecular subtypes of breast cancer receptors in Togolese patients and to establish the correlation between clinical and histological data and molecular types.

Methods

Clinicopathologic data of patients were collected from clinical records. Immunohistochemistry biomarkers (ER, PR, and HER2) were assessed in patients who have been diagnosed with invasive breast cancer from March 2016 to March 2020 in the department of oncology. The analysis of variance and the Chi-square Test was used to analyze the data.

Results

A total of 117 cases were collected. The mean age of patients was 52.05 ± 12.38 with an age range of 30 to 85 years. Half of the patients were over 50 years old and the majority (70.9%) was postmenopausal. More than half of patients (52.1%) presented with T3-T4tumors.The most common histologic subtype of breast cancer was invasive ductal carcinoma of no special type (95.7%). Tumors grade 2 were predominant (51.3%) followed by grade 3 (42.7%). Advanced carcinomas were found in 69 patients (59%). The percentage of ER+, PR+, and HER2 positive tumors was 54.7%, 41%, and 15.4% respectively. The predominant molecular subtype was Triple negative (37.6%), followed by Luminal A (30.8.7%), Luminal B subtype (23.9%), and HER2 enriched (7.7%). There was a significant association between stage and breast cancer subtypes (p 0.025), histologic grade, and subtype (p < 0.0001) but no correlation was found with age, menopausal status, and tumor size.

Conclusion

Breast carcinoma in our patients are high grade tumors and are diagnosed at an advanced stage. Triple negative and Luminal A are the two predominant breast cancer subtypes in Togolese women. Consequently, Receptor testing availability should be a priority to offer the best breast cancer treatment.

Frequency and spectrum of mutations across 94 cancer predisposition genes in African American women with invasive breast cancer

African American women are at increased risk of being diagnosed at a young age and/or with triple negative breast cancer, both factors which are included in current guidelines for identifying women who may benefit from genetic testing. Commercial breast cancer predisposition genetic panels, based largely on data derived from women of European ancestry, may not capture the full spectrum of cancer predisposition genes associated with breast cancer in African American women. Between 2001 and 2018, 488 unselected African American women with invasive breast cancer enrolled in the Clinical Breast Care Project. National Comprehensive Cancer Network (NCCN) Hereditary Cancer testing criteria version 1.2020 were applied to determine genetic risk. Targeted sequencing was performed using the TruSight Cancer panel and variants classified using the ClinVar database. Using NCCN criteria, 64.1% of African American women would be eligible for genetic testing. Fifty pathogenic or likely pathogenic mutations were detected in 19 genes with the highest frequencies in BRCA2 (29.4%) and BRCA1 (15.7%). Mutation frequencies in test-eligible and test-ineligible women were 13.1% and 3.5%, respectively. One-third of women harbored variants that could not be classified. While these data do not suggest a need to expand current commercial gene panels, NCCN criteria would fail to identify 12.5% of African American women with mutations in hereditary cancer predisposing genes.

Breast cancer pathology services in sub-Saharan Africa: a survey within population-based cancer registries

BACKGROUND

Pathologists face major challenges in breast cancer diagnostics in sub-Saharan Africa (SSA). The major problems identified as impairing the quality of pathology reports are shortcomings of equipment, organization and insufficiently qualified personnel. In addition, in the context of breast cancer, immunohistochemistry (IHC) needs to be available for the evaluation of biomarkers. In the study presented, we aim to describe the current state of breast cancer pathology in order to highlight the unmet needs.

METHODS

We obtained information on breast cancer pathology services within population-based cancer registries in SSA. A survey of 20 participating pathology centres was carried out. These centres represent large, rather well-equipped pathologies. The data obtained were related to the known population and breast cancer incidence of the registry areas.

RESULTS

The responding pathologists served populations of between 30,000 and 1.8 million and the centres surveyed dealt with 10-386 breast cancer cases per year. Time to fixation and formalin fixation time varied from overnight to more than 72 h. Only five centres processed core needle biopsies as a daily routine. Technical problems were common, with 14 centres reporting temporary power outages and 18 centres claiming to own faulty equipment with no access to technical support. Only half of the centres carried out IHC in their own laboratory. For three centres, IHC was only accessible outside of the country and one centre could not obtain any IHC results. A tumour board was established in 13 centres.

CONCLUSIONS

We conclude that breast cancer pathology services ensuring state-of-the-art therapy are only available in a small fraction of centres in SSA. To overcome these limitations, many of the centres require larger numbers of experienced pathologists and technical staff. Furthermore, equipment maintenance, standardization of processing guidelines and establishment of an IHC service are needed to comply with international standards of breast cancer pathology.

Prevalence of Histological Characteristics of Breast Cancer in Rwanda in Relation to Age and Tumor Stages

Breast cancer is a complex disease, and it is the most common cause of morbidity and mortality among women worldwide. In Sub-Saharan Africa, the clinical characteristics and tumor profiles of breast cancer are still unknown. In the present study we aimed to determine breast tumor profiles of the Rwandan patients in relation to age and tumor stages. We compare our findings to related results from other sub-Saharan Africa studies. Data on age at diagnosis, tumor stage, and hormonal profiles of 138 patients diagnosed between January 2015 and December 2018 were retrospectively retrieved from electronic medical records at three referral hospitals in Rwanda. We compared our results to related findings reported in other Sub-Saharan African countries. All statistical analyses were done using SPSS Inc., Chicago, IL, USA, version 20 and R software languages. The mean age at diagnosis was 49.7 years (SD = 13) and ranged from 17 to 86 years. The majority of patients (57.2%) were diagnosed before 50 years of age compared with 42.8% aged > 50 years. Tumor stage III was the commonest accounting for 62% followed by stage II with 24.8%. The distribution of breast tumor subtypes was ER-, PR-, HER2-: 37.7%; ER+, PR+, HER2-: 31.2%; ER-, PR-, HER2+: 14.5%; ER+, PR+, HER2+: 5.1%; and other subtypes represented 11.6%. There was no statistically significant difference in age and tumor stages between the molecular subtypes. Our findings revealed the predominance of hormonal negative tumors among Rwandan patients with breast cancer. Triple negative was found to be the most common breast tumor subtype regardless of age and tumor stage. Larger prospective studies could examine genetics and environmental factors that may play a role in the differences of tumor characteristics in Sub-Saharan populations.

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

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

Breast cancer in Tanzanian, black American, and white American women: An assessment of prognostic and predictive features, including tumor infiltrating lymphocytes

Introduction

Breast cancer is a major cause of morbidity and mortality for women in Sub-Saharan Africa and for black American women. There is evidence that the pathologic characteristics of breast cancers in both African women and black American women may differ from their counterparts of European ancestry. However, despite the great burden of disease, data on pathologic features of breast carcinoma in Sub-Saharan Africa is limited and often contradictory. This lack of information makes it difficult to prioritize resource use in efforts to improve breast cancer outcomes in the region.

Methods

We examined consecutive cases of breast cancer in Tanzanian women (n = 83), black American women (n = 120), and white American women (n = 120). Each case was assessed for tumor type, grade, mitotic count, ER and HER2 status, and tumor infiltrating lymphocyte involvement.

Results

The Tanzanian subjects were younger and had higher stage tumors than the subjects in either American group. Breast cancers in the Tanzanian and black American groups were more likely to be high grade (p = 0.008), to have a high mitotic rate (p<0.0001), and to be ER-negative (p<0.001) than the tumors in the white American group. Higher levels of tumor infiltrating lymphocyte involvement were seen among Tanzanian and black American subjects compared to white American subjects (p = 0.0001). Among all subjects, tumor infiltrating lymphocyte levels were higher in tumors with a high mitotic rate. Among Tanzanian and black American subjects, tumor infiltrating lymphocyte levels were higher in ER-negative tumors. These findings have implications for treatment priorities for breast cancer in Tanzania and other Sub-Saharan African countries.

Androgen Receptor and ALDH1 Expression Among Internationally Diverse Patient Populations

Purpose

Population-based incidence rates of breast cancers that are negative for estrogen receptor (ER), progesterone receptor, and human epidermal growth factor receptor 2/neu (triple-negative breast cancer [TNBC]) are higher among African American (AA) compared with white American (WA) women, and TNBC prevalence is elevated among selected populations of African patients. The extent to which TNBC risk is related to East African versus West African ancestry, and whether these associations extend to expression of other biomarkers, is uncertain.

Methods

We used immunohistochemistry to evaluate estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2/neu, androgen receptor and aldehyde dehydrogenase 1 (ALDH1) expression among WA (n = 153), AA (n = 76), Ethiopian (Eth)/East African (n = 90), and Ghanaian (Gh)/West African (n = 286) patients with breast cancer through an institutional review board–approved international research program.

Results

Mean age at diagnosis was 43, 49, 60, and 57 years for the Eth, Gh, AA, and WA patients, respectively. TNBC frequency was higher for AA and Gh patients (41% and 54%, respectively) compared with WA and Eth patients (23% and 15%, respectively; P < .001) Frequency of ALDH1 positivity was higher for AA and Gh patients (32% and 36%, respectively) compared with WA and Eth patients (23% and 17%, respectively; P = .007). Significant differences were observed for distribution of androgen receptor positivity: 71%, 55%, 42%, and 50% for the WA, AA, Gh, and Eth patients, respectively (P = .008).

Conclusion

Extent of African ancestry seems to be associated with particular breast cancer phenotypes. West African ancestry correlates with increased risk of TNBC and breast cancers that are positive for ALDH1.

A Review of the Hereditary Component of Triple Negative Breast Cancer: High- and Moderate-Penetrance Breast Cancer Genes, Low-Penetrance Loci, and the Role of Nontraditional Genetic Elements

Triple negative breast cancer (TNBC), representing 10-15% of breast tumors diagnosed each year, is a clinically defined subtype of breast cancer associated with poor prognosis. The higher incidence of TNBC in certain populations such as young women and/or women of African ancestry and a unique pathological phenotype shared between TNBC and BRCA1-deficient tumors suggest that TNBC may be inherited through germline mutations. In this article, we describe genes and genetic elements, beyond BRCA1 and BRCA2, which have been associated with increased risk of TNBC. Multigene panel testing has identified high- and moderate-penetrance cancer predisposition genes associated with increased risk for TNBC. Development of large-scale genome-wide SNP assays coupled with genome-wide association studies (GWAS) has led to the discovery of low-penetrance TNBC-associated loci. Next-generation sequencing has identified variants in noncoding RNAs, viral integration sites, and genes in underexplored regions of the human genome that may contribute to the genetic underpinnings of TNBC. Advances in our understanding of the genetics of TNBC are driving improvements in risk assessment and patient management.

Atypical Chemokine Receptor 1 (DARC/ACKR1) in Breast Tumors Is Associated with Survival, Circulating Chemokines, Tumor-Infiltrating Immune Cells, and African Ancestry

BACKGROUND

Tumor-specific immune response is an important aspect of disease prognosis and ultimately impacts treatment decisions for innovative immunotherapies. The atypical chemokine receptor 1 (ACKR1 or DARC) gene plays a pivotal role in immune regulation and harbors several single-nucleotide variants (SNV) that are specific to sub-Saharan African ancestry.

METHODS

Using computational The Cancer Genome Atlas (TCGA) analysis, case-control clinical cohort Luminex assays, and CIBERSORT deconvolution, we identified distinct immune cell profile-associated DARC/ACKR1 tumor expression and race with increased macrophage subtypes and regulatory T cells in DARC/ACKR1-high tumors.

RESULTS

In this study, we report the clinical relevance of DARC/ACKR1 tumor expression in breast cancer, in the context of a tumor immune response that may be associated with sub-Saharan African ancestry. Briefly, we found that for infiltrating carcinomas, African Americans have a higher proportion of DARC/ACKR1-negative tumors compared with white Americans, and DARC/ACKR1 tumor expression is correlated with proinflammatory chemokines, CCL2/MCP-1 (P <0.0001) and anticorrelated with CXCL8/IL8 (P <0.0001). Sub-Saharan African-specific DARC/ACKR1 alleles likely drive these correlations. Relapse-free survival (RFS) and overall survival (OS) were significantly longer in individuals with DARC/ACKR1-high tumors (P <1.0 × 10-16 and P <2.2 × 10-6, respectively) across all molecular tumor subtypes.

CONCLUSIONS

DARC/AKCR1 regulates immune responses in tumors, and its expression is associated with sub-Saharan African-specific alleles. DARC/ACKR1-positive tumors will have a distinct immune response compared with DARC/AKCR1-negative tumors.

IMPACT

This study has high relevance in cancer management, as we introduce a functional regulator of inflammatory chemokines that can determine an infiltrating tumor immune cell landscape that is distinct among patients of African ancestry.

An Interactive Resource to Probe Genetic Diversity and Estimated Ancestry in Cancer Cell Lines

Recent work points to a lack of diversity in genomics studies from genome-wide association studies to somatic (tumor) genome analyses. Yet, population-specific genetic variation has been shown to contribute to health disparities in cancer risk and outcomes. Immortalized cancer cell lines are widely used in cancer research, from mechanistic studies to drug screening. Larger collections of cancer cell lines better represent the genomic heterogeneity found in primary tumors. Yet, the genetic ancestral origin of cancer cell lines is rarely acknowledged and often unknown. Using genome-wide genotyping data from 1,393 cancer cell lines from the Catalogue of Somatic Mutations in Cancer (COSMIC) and Cancer Cell Line Encyclopedia (CCLE), we estimated the genetic ancestral origin for each cell line. Our data indicate that cancer cell line collections are not representative of the diverse ancestry and admixture characterizing human populations. We discuss the implications of genetic ancestry and diversity of cellular models for cancer research and present an interactive tool, Estimated Cell Line Ancestry (ECLA), where ancestry can be visualized with reference populations of the 1000 Genomes Project. Cancer researchers can use this resource to identify cell line models for their studies by taking ancestral origins into consideration.

Health Behaviors and Lifestyle Interventions in African American Breast Cancer Survivors: A Review

Background: African American breast cancer survivors have a higher incidence of estrogen receptor negative and basal-like (e.g., triple negative) tumors, placing them at greater risk for poorer survival when compared to women of other racial and ethnic groups. While access to equitable care, late disease stage at diagnosis, tumor biology, and sociodemographic characteristics contribute to health disparities, poor lifestyle characteristics (i.e., inactivity, obesity, and poor diet) contribute equally to these disparities. Lifestyle interventions hold promise in shielding African American survivors from second cancers, comorbidities, and premature mortality, but they are often underrepresented in studies promoting positive behaviors. This review examined the available literature to document health behaviors and lifestyle intervention (i.e., obesity, physical activity, and sedentary behavior) studies in African American breast cancer survivors. Methods: We used PubMed, Academic Search Premier, and Scopus to identify cross-sectional and intervention studies examining the lifestyle behaviors of African American breast cancer survivors. Identified intervention studies were assessed for risk of bias. Other articles were identified and described to provide context for the review. Results: Our systematic review identified 226 relevant articles. The cross-sectional articles indicated poor adherence to physical activity and dietary intake and high rates of overweight and obesity. The 16 identified intervention studies indicated reasonable to modest study adherence rates (>70%), significant reductions in weight (range -1.9 to -3.6%), sedentary behavior (-18%), and dietary fat intake (range -13 to -33%) and improvements in fruit and vegetable intake (range +25 to +55%) and physical activity (range +13 to +544%). The risk of bias for most studies were rated as high (44%) or moderate (44%). Conclusions: The available literature suggests that African American breast cancer survivors adhere to interventions of various modalities and are capable of making modest to significant changes. Future studies should consider examining (a) mediators and moderators of lifestyle behaviors and interventions, (b) biological outcomes, and (c) determinants of enhanced survival in this population.

Racial Disparity and Triple-Negative Breast Cancer in African-American Women: A Multifaceted Affair between Obesity, Biology, and Socioeconomic Determinants

Triple negative breast cancer (TNBC) is a molecularly heterogeneous disease whose incidence is disproportionately higher in African American (AA) women compared to European American (EA) women. Earlier onset, more advanced stage at diagnosis, and aggressive tumor phenotype are some of the characteristic features of TNBC in women with African ethnicity in comparison to EA women, denoting one of the most significant examples of racial disparity in oncology. It is still contentious whether health disparities result in aggressive behavior of TNBC in AA women or it is indeed a molecularly distinct disease. Given the “gaps-in-knowledge” surrounding racial disparity in TNBC, this review discusses various socioeconomic factors and the genetic predispositions contributing to poor prognosis of TNBC in AA women. While socioeconomic factors may contribute to poorer survival, multiple preclinical and clinical studies suggest inherent genetic risk factors and aberrant activation of oncogenic pathways in AA TNBC. Additionally, AA women are more likely to be obese and obesity is known to drive a molecular circuitry resulting in aggressive tumor progression indicating a potential obesity-TNBC axis at work in AA women. Given the multifactorial nature of AA TNBC, a transdisciplinary approach may help bridge the disparity that exists between AA and EA TNBC.

Addition of triple negativity of breast cancer as an indicator for germline mutations in predisposing genes increases sensitivity of clinical selection criteria

Background

Breast cancer is the most common cancer in women. 12–15% of all tumors are triple-negative breast cancers (TNBC). So far, TNBC has been mainly associated with mutations in BRCA1. The presence of other predisposing genes seems likely since DNA damage repair is a complex process that involves several genes. Therefore we investigated if mutations in other genes are involved in cancer development and whether TNBC is an additional indicator of mutational status besides family history and age of onset.

Methods

We performed a germline panel-based screening of 10 high and low-moderate penetrance breast cancer susceptibility genes (BRCA1, BRCA2, ATM, CDH1, CHEK2, NBN, PALB2, RAD51C, RAD51D and TP53) in 229 consecutive individuals affected with TNBC unselected for age, family history or bilateral disease. Within this cohort we compared the number of mutation carriers fulfilling clinical selection criteria with the total number of carriers identified.

Results

Age at diagnosis ranged from 23 to 80 years with an average age of 50.2 years. In 57 women (24.9%) we detected a pathogenic mutation, with a higher frequency (29.7%) in the group manifesting cancer before 60 years. Deleterious BRCA1 mutations occurred in 14.8% of TNBC patients. These were predominantly recurrent frameshift mutations (24/34, 70.6%). Deleterious BRCA2 mutations occurred in 5.7% of patients, all but one (c.1813dupA) being unique.

While no mutations were found in CDH1 and TP53, 10 mutations were detected in one of the six other predisposition genes. Remarkably, neither of the ATM, RAD51D, CHEK2 and PALB2 mutation carriers had a family history. Furthermore, patients with non-BRCA1/2 mutations were not significantly younger than mutation negative women (p = 0.3341). Most importantly, among the 57 mutation carriers, ten (17.5%) would be missed using current clinical testing criteria including five (8%) with BRCA1/2 mutations.

Conclusions

In summary, our data confirm and expand previous studies of a high frequency of germline mutations in genes associated with ineffective repair of DNA damage in women with TNBCs. Neither age of onset, contralateral disease nor family history were able to discern all mutation positive individuals. Therefore, TNBC should be considered as an additional criterion for panel based genetic testing.

Breast Cancer Disparities: How Can We Leverage Genomics to Improve Outcomes?

Breast cancer mortality rates are higher in African American compared with white American women. Disproportionately rising incidence rates, coupled with higher rates of biologically aggressive disease among African Americans is resulting in a widening of the mortality disparity. Higher rates of triple-negative breast cancer among African American women, as well as women from western sub-Saharan Africa, has prompted questions regarding the role of African ancestry as a marker of hereditary susceptibility for specific disease phenotypes. Advances in germline genetics, as well as somatic tumor genomic research, hold great promise in the effort to understand the biology of breast cancer variations between different population subsets.