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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

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

Supplementary Data from 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

Women of sub-Saharan African ancestry have disproportionately higher incidence of aggressive, early-onset Triple Negative Breast Cancer (TNBC), and TNBC mortality across all race groups. Population-based comparative studies show racial differences in TNBC tumor biology, with higher prevalence of basal-like and Quadruple-Negative subtypes in African Americans (AA). However, most investigations relied on self-reported race (SRR) of primarily United States (US) populations. However, given that genetic admixture in AAs is extremely heterogenous, and race-correlated social determinants can translate into biological differences, the true association of African ancestry with TNBC biology and gene expression is currently unclear. To address this, we conducted RNAseq on an international cohort of AAs, west and east Africans with TNBC. Using genetic ancestry estimation in this African-enriched cohort, we identified 613 genes associated with African ancestry and more than 2200 genes associated with regional-level African ancestry. Functional enrichment and deconvolution revealed tumor-associated immune cell infiltration and activity.STATEMENT OF SIGNIFICANCEUsing a rigorous ancestry quantification process, we show that TNBC has ancestry-associated gene expression profiles, linked to immunological landscapes, which may contribute to racial differences in clinical outcomes. This is the first study to show the definitive link to tumor immunological landscape, associated with African ancestry, using a multiethnic African-enriched cohort.

To investigate subtype-specific risk of germline alleles associated with triple negative breast cancer (TNBC) in African ancestry populations.Breast cancer (BC) mortality is higher in African American (AA) compared to White American (WA) women; this disparity is partly explained by 2-fold higher TNBC incidence.We used a surgically maintained biospecimen cohort of 2884 BC cases. Subsets of the total (760 AA; 962 WA; 910 West African/Ghanaian; 252 East African/Ethiopian) were analyzed for genotypes of candidate alleles. A subset of 417 healthy controls were also genotyped, to measure associations with overall BC risk and TNBC.TNBC frequency was highest in Ghanaian and AA cases (49% and 44% respectively; P0.0001) and lowest in Ethiopian and WA cases (17% and 24% respectively; P0.0001). TNBC cases had higher West African ancestry than non-TNBC (P0.0001). Frequency of the Duffy-null allele (rs2814778; an African ancestral variant adopted under selective pressure as protection against malaria) was associated with TNBC-specific risk (P0.0001), quantified West African Ancestry (P0.0001) and was more common in AA, Ghanaians, and TNBC cases. Additionally, rs4849887 was significantly associated with overall BC risk, and both rs2363956 and rs13000023 were associated with TNBC-specific risk, although none as strongly as the Duffy-null variant.West African ancestry is strongly correlated with TNBC status, as well as germline variants related to BC risk. The Duffy-null allele was associated with TNBC risk in our cohort.

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.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.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.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.

DARC/ACKR1 erythrocyte expression, also known as the “Duffy blood group,” is understood to sequester pro-inflammatory chemokines and thereby regulate circulating gradients that direct immune cell infiltration. We hypothesize that this function also determines immune cell landscapes in the tumor microenvironment. Due to evolutionary selection pressures of malaria, individuals with sub-Saharan African ancestry typically carry the Duffy-null allele (rs4849887) and this lack of DARC/ACKR1 expression gives immunity to malaria while also allowing chronically high inflammation levels. Over 68% of African Americans (AA) have been found to have the Duffy-null genotype, compared to a rare 1-3% in European American individuals and we have shown it increases predisposition for Triple-Negative Breast Cancer (TNBC). In addition, we are currently studying if Duffy-null may contribute to higher breast cancer mortality that disproportionately affects AA women. This may be in part due to the role that low-DARC/ACKR1 expression plays in chronic inflammation, altering levels of several chemokines that modulate the migration and differentiation of specific immune cells. This role will impact tumor immune cell infiltration as well as the immune cell population composition overall, depending upon levels of DARC/ACKR1. Using RNA sequencing, our initial results indicated that for breast cancer tumors with high DARC/ACKR1 expression there was a higher estimated presence of CD8+ T cells, CD4+ T cells, regulatory T cells, follicular helper T cells, and memory B cells. Whereas with low DARC/ACKR1 expression, there was markedly less expression of resting dendritic cells and memory B cells. Therefore, in order to ascertain the influence DARC status has on spatial deposition and functional status of immune cell landscapes across the tumor microenvironment, we performed imaging mass cytometry on primary TNBC tumors. The panel contained tumor, structural, and immune markers, and was used to characterize the spatial differences between samples that had been verified to be DARC-high or DARC-low through immunohistochemistry. Our imaging analyses indicated that high DARC/ACKR1 expression correlates with infiltration of monocytes, macrophages, and cytotoxic T cells into the solid tumor microenvironment. Conversely, tumors with low DARC/ACKR1 expression showed monocytes and cytotoxic T cells contained in the tumor stroma. Using single-cell phenotyping, we were also able to identify distinct cell populations between DARC-high and -low. The tSNE analysis and heatmaps performed using Histology Topography Cytometry Analysis Toolbox (histoCAT), allowed us to visualize the spatial distribution of these cell populations, indicating an immune-suppressive tumor microenvironment in DARC-low tumors. These differences may be implicated in the causality of tumor progression as well as how to approach treatment given the cell heterogeneity of TNBC. This work provides greater context on the role that Duffy-null plays in chronic inflammation on the tumor microenvironment. Citation Format: Yanira Guerra, Rachel Martini, Jessica Bensenhaver, Yalei Chen, Joseph K. Oppong, Ishmael Kyei, Frances S. Aitpillah, Michael O. Adinku, Joseph K. Oppong, Ernest K. Adjei, Aisha Jibril, Baffour Awuah, Mahteme Bekele, Engida Abebe, Kwasi Ankomah, Ernest B. Osei-Bonsu, Kofi K. Gyan, Clayton Yates, Kim Blenman, Olivier Elemento, Lisa Newman, Melissa B. Davis. The role of African Duffy-null allele related inflammation on the tumor microenvironment [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-141.

Purpose Breast cancer, the most common cancer worldwide, is the leading cause of cancer mortality in Ghanaian women. Previous studies find Ghanaian women are diagnosed at a younger age and at more advanced stages (III and IV), and have tumors with characteristics similar to African American women. We sought to remedy gaps in knowledge about breast cancer survival in Ghana and its relation to demographic and biologic factors of the tumors at diagnosis to assist in cancer control and registration planning. Methods Individuals with a breast cancer diagnosis who sought care at Komfo Anokye Teaching Hospital from 2009 to 2014 were identified via medical records. Follow-up telephone interviews were held to assess survival. Kaplan-Meier plots and Cox proportional hazards models assessed survival associated with clinical and demographic characteristics. Results A total of 223 patients completed follow-up and were analyzed. The median survival was 3.8 years. Approximately 50% of patients were diagnosed with grade 3 tumors, which significantly increased the risk of recurrence or death (hazard ratio [HR] for grade 2 versus 1, 2.98; 95% CI, 1.26 to 7.02; HR grade 3 v 1, 2.56; 95% CI, 1.08 to 6.07; P = .04). No other variables were significantly associated with survival. Conclusion Higher tumor grade was significantly associated with shorter survival, indicating impact of aggressive biology at diagnosis on higher risk of cancer spread and recurrence. Contrary to prevailing notions, telephone numbers were not reliable for follow-up. Collecting additional contact information will likely contribute to improvements in patient care and tracking. A region-wide population-based active registry is important to implement cancer control programs and improve survival in sub-Saharan Africa.

Background Significant clinical and research applications are driving large scale adoption of individualized tumor sequencing in cancer in order to identify tumors-specific mutations. When a matched germline sample is available, somatic mutations may be identified using comparative callers. However, matched germline samples are frequently not available such as with archival tissues, which makes it difficult to distinguish somatic from germline variants. While population databases may be used to filter out known germline variants, recent studies have shown private germline variants result in an inflated false positive rate in unmatched tumor samples, and the number germline false positives in an individual may be related to ancestry. Methods First, we examined the relationship between the germline false positives and ancestry. Then we developed and implemented a tumor only caller (LumosVar) that leverages differences in allelic frequency between somatic and germline variants in impure tumors. We used simulated data to systematically examine how copy number alterations, tumor purity, and sequencing depth should affect the sensitivity of our caller. Finally, we evaluated the caller on real data. Results We find the germline false-positive rate is significantly higher for individuals of non-European Ancestry largely due to the limited diversity in public polymorphism databases and due to population-specific characteristics such as admixture or recent expansions. Our Bayesian tumor only caller (LumosVar) is able to greatly reduce false positives from private germline variants, and our sensitivity is similar to predictions based on simulated data. Conclusions Taken together, our results suggest that studies of individuals of non-European ancestry would most benefit from our approach. However, high sensitivity requires sufficiently impure tumors and adequate sequencing depth. Even in impure tumors, there are copy number alterations that result in germline and somatic variants having similar allele frequencies, limiting the sensitivity of the approach. We believe our approach could greatly improve the analysis of archival samples in a research setting where the normal is not available. Electronic supplementary material The online version of this article (10.1186/s12920-017-0296-8) contains supplementary material, which is available to authorized users.

To design interventions to reduce the burden of breast cancer (BC) in women with African ancestry, there is the need to understand the factors - heritable or non-heritable, modifiable or non-modifiable - that are associated with the disease. Patients and tumors from black women have been underrepresented in clinical research which are the main route to identifying new and improved treatments. Triple negative breast cancer (TNBC) is a clinically aggressive form of BC with propensity to metastasize and is enriched in patients with hereditary predisposition to BC. TNBC is most prevalent among black women despite lacking strong links with the known BC. This phenotype prevalence contributes to disparities in BC outcomes between blacks and other populations. There is an urgent need to represent black tumors in clinical research. Here we describe the process we used to transport fresh breast tumors from Ghana, west Africa to the USA to develop PDXs. Considering the shared ancestry between west Africans and diasporan African American, the results of this work will benefit both populations. Through an international collaboration between investigators at University of Michigan (UM) and Komfo Anokye Teaching Hospital (KATH) in Ghana, regular team site visits were initiated to generate surgical specimens for transport to the United States of America (USA). These specimens were used to create in vivo models. With informed consent, excess patient tumor tissue was taken from the operating room, at KATH. The tumors were cut into small pieces, and slow- frozen to -80°C in 10% DMSO/90%FBS. The samples were then transported overnight on dry ice in a commercial flight to UM. At UM, the tumor pieces were rapidly thawed and rinsed off with HBSS or PBS. The tumor sample was cut into smaller fragments (approximately 1-2 mm in diameter), mixed with matrigel (BD), and 25 μl of matrigel per injection site was injected into the mammary fat pad of female NOD/scid/IL2Rgnull (NSG) mice with an 18-gauge needle. From 2012 to 2017, we obtained fresh tumor samples from 49 Ghanaian patients. Of these, 23 (47%) were TNBC and 26 (53%) were other subtypes. Of the 23 TNBC samples, we implanted 18 into NSG mice and developed PDXs from 12. This gave us a success rate of 67%. We have fully characterized these tumors and their corresponding primary tumors. Our results demonstrate a maintenance of the histology and marker expression in the corresponding PDXs. Additionally, we obtained samples and developed PDXs from 17 Caucasian Americans, 13 African Americans, and 2 Asian patients from UM. 20 samples were TNBCs and 13 were non-TNBC. 18 were implanted in mice (12 TNBC, 4 ER+, and 2 Her2+). Of these, 11 developed into PDXs (9 TNBC, 2 ER+). Transporting African tumors to the USA is expensive, challenging, and limits large scale studies. These challenges can be overcome by enhancing African based research resources in order to conduct research in Africa. Citation Format: Evelyn M. Jiagge, Tahra K. Suhan, Jessica M. Bensenhaver, Michele Dziubinski, Joseph K. Oppong, Francis Aitpillah, Awuah Baffour, John D. Carpten, Lisa A. Newman, Sofia D. Merajver, Max S. Wicha. Creating PDXs from continental African breast tumors: addressing racial inequity through science [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2996.

Triple-negative breast cancer (TNBC) is more common among African American (AA) and western sub-Saharan African breast cancer (BC) patients compared with White/Caucasian Americans (WA) and Europeans. Little is known about TNBC in east Africa. Invasive BC diagnosed 1998–2014 were evaluated: WA and AA patients from the Henry Ford Health System in Detroit, Michigan; Ghanaian/west Africans from the Komfo Anokye Teaching Hospital in Kumasi, Ghana; and Ethiopian/east Africans from the St. Paul’s Hospital Millennium Medical College in Addis Ababa, Ethiopia. Histopathology and immunohistochemistry for estrogen receptor (ER), progesterone receptor (PR), and HER2/neu expression was performed in Michigan on formalin-fixed, paraffin-embedded samples from all cases. A total of 234 Ghanaian (mean age 49 years), 94 Ethiopian (mean age 43 years), 272 AA (mean age 60 years), and 321 WA (mean age 62 years; p = 0.001) patients were compared. ER-negative and TNBC were more common among Ghanaian and AA compared with WA and Ethiopian cases (frequency ER-negativity 71.1 and 37.1 % vs. 19.8 and 28.6 % respectively, p

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.

The androgen receptor (AR) is a commonly-expressed hormone receptor in breast cancer and may be a marker of response to targeted anti-androgen therapy, a particularly attractive option for triple-negative breast cancer (TNBC). Gene expression studies suggest that ARs may distinguish a luminal/AR TNBC subtype from stem cell-like subtypes. TNBC frequency is two to three times higher in African American and African breast cancers compared with White American and European breast cancers, yet little is known regarding TNBC subtypes in high-frequency African-ancestry populations. We evaluated ARs and the mammary stem cell marker aldehyde dehydrogenase 1 (ALDH1) among breast cancers from Ghana, Africa.Overall, 147 formalin-fixed, paraffin-embedded invasive breast cancers from the Komfo Anoyke Teaching Hospital in Ghana were studied at the University of Michigan, and analyzed immunohistochemically for estrogen receptor (ER), progesterone receptor (PR), HER2/neu, ALDH1, and AR expression.The median age of patients was 45 years. Only 31 cases (21 %) were ER-positive, and 14 (10 %) were HER2-positive; 89 (61 %) were TNBCs. For the entire group, 44 % were AR-positive and 45 % were ALDH1-positive. ER/PR-positive tumors were more likely to be AR-positive compared with ER/PR-negative tumors (87 vs. 26 %; p0.0001), but there was no association between ALDH1 and AR expression. Among the TNBC cases, 45 % were ALDH1-positive and 24 % were AR-positive. ALDH1 positivity was associated with AR positivity within the subset of TNBC (36 vs. 14 %; p = 0.019).We confirmed other studies showing a high frequency of TNBC in Africa. Surprisingly, ALDH1 was found to correlate with AR expression among TNBC, suggesting that novel TNBC subtypes may exist among populations with African ancestry.

Disparities in breast cancer incidence and outcome between African American and white American women are multifactorial in etiology. The increased frequency of triple-negative breast cancers (TNBC) in African American patients suggests the possible contribution of hereditary factors related to African ancestry. The University of Michigan (UM)-Komfo Anoyke Teaching Hospital (KATH) Breast Cancer Research Collaborative and International Breast Registry was established in 2004. It features epidemiologic information, tumor tissue, and germline DNA specimens from African American, white American, and Ghanaian women. This research collaborative has generated valuable findings regarding the pathogenesis and patterns of TNBC while concomitantly improving the standard of breast oncology care in Ghana. This partnership has also yielded important opportunities for academic and educational exchange. It has expanded to involve other sites in Africa and Haiti. The UM-KATH collaborative is a model for demonstrating the research and academic exchange value of international partnerships.

Women with African ancestry in western, sub-Saharan Africa and in the United States represent a population subset facing an increased risk of being diagnosed with biologically aggressive phenotypes of breast cancer that are negative for the estrogen receptor, the progesterone receptor, and the HER2/neu marker. These tumors are commonly referred to as triple-negative breast cancer. Disparities in breast cancer incidence and outcome related to racial or ethnic identity motivated the establishment of the International Breast Registry, on the basis of partnerships between the Komfo Anokye Teaching Hospital in Kumasi, Ghana, the University of Michigan Comprehensive Cancer Center in Ann Arbor, Michigan, and the Henry Ford Health System in Detroit, Michigan. This research collaborative has featured educational training programs as well as scientific investigations related to the comparative biology of breast cancer in Ghanaian African, African American, and white/European American patients. Currently, the International Breast Registry has expanded to include African American patients throughout the United States by partnering with the Sisters Network (a national African American breast cancer survivors’ organization) and additional sites in Ghana (representing West Africa) as well as Ethiopia (representing East Africa). Its activities are now coordinated through the Henry Ford Health System International Center for the Study of Breast Cancer Subtypes. Herein, we review the history and results of this international program at its 10-year anniversary.

BACKGROUND: In case-control studies, population controls can help ensure generalizability; however, the selection of population controls can be challenging in environments that lack population registries. We developed a population enumeration and sampling strategy to facilitate use of population controls in a breast cancer case-control study conducted in Ghana.METHODS: Household enumeration was conducted in 110 census-defined geographic areas within Ghana's Ashanti, Central, Eastern, and Greater Accra Regions. A pool of potential controls (women aged 18 to 74 years, never diagnosed with breast cancer) was selected from the enumeration using systematic random sampling and frequency-matched to the anticipated distributions of age and residence among cases. Multiple attempts were made to contact potential controls to assess eligibility and arrange for study participation. To increase participation, we implemented a refusal conversion protocol in which initial non-participants were re-approached after several months.RESULTS: 2,528 women were sampled from the enumeration listing, 2,261 (89%) were successfully contacted, and 2,106 were enrolled (overall recruitment of 83%). 170 women were enrolled through refusal conversion. Compared with women enrolled after being first approached, refusal conversion enrollees were younger and less likely to complete the study interview in the study hospital (13% vs. 23%). The most common reasons for non-participation were lack of interest and lack of time.CONCLUSIONS: Using household enumeration and repeated contacts, we were able to recruit population controls with a high participation rate. Our approach may provide a blue-print for others undertaking epidemiologic studies in populations that lack accessible population registries.

Although breast cancer is becoming more prevalent in Africa, few epidemiologic studies have been undertaken and appropriate methodologic approaches remain uncertain. We therefore conducted a population-based case-control study in Accra and Kumasi, Ghana, enrolling 2,202 women with lesions suspicious for breast cancer and 2,161 population controls. Biopsy tissue for cases prior to neoadjuvant therapy (if given), blood, saliva and fecal samples were sought for study subjects. Response rates, risk factor prevalences and odds ratios for established breast cancer risk factors were calculated. A total of 54.5% of the recruited cases were diagnosed with malignancies, 36.0% with benign conditions and 9.5% with indeterminate diagnoses. Response rates to interviews were 99.2% in cases and 91.9% in controls, with the vast majority of interviewed subjects providing saliva (97.9% in cases vs. 98.8% in controls) and blood (91.8% vs. 82.5%) samples; lower proportions (58.1% vs. 46.1%) provided fecal samples. While risk factor prevalences were unique as compared to women in other countries (e.g., less education, higher parity), cancer risk factors resembled patterns identified elsewhere (elevated risks associated with higher levels of education, familial histories of breast cancer, low parity and larger body sizes). Subjects with benign conditions were younger and exhibited higher socioeconomic profiles (e.g., higher education and lower parity) than those with malignancies, suggesting selective referral influences. While further defining breast cancer risk factors in Africa, this study showed that successful population-based interdisciplinary studies of cancer in Africa are possible but require close attention to diagnostic referral biases and standardized and documented approaches for high-quality data collection, including biospecimens.

This abstract was withdrawn by the authors.

BACKGROUND: Breast cancers that are negative for the estrogen receptor (ER), the progesterone receptor (PR), and the HER2 (human epidermal growth factor receptor 2) marker are more prevalent among African women, and the biologically aggressive nature of these triple-negative breast cancers (TNBCs) may be attributed to their mammary stem cell features. Little is known about expression of the mammary stem cell marker aldehyde dehydrogenase 1 (ALDH1) in African women. Novel data are reported regarding ALDH1 expression in benign and cancerous breast tissue of Ghanaian women. METHODS: Formalin-fixed, paraffin-embedded specimens were transported from the Komfo Anoyke Teaching Hospital in Kumasi, Ghana to the University of Michigan for centralized histopathology study. Expression of ER, PR, HER2, and ALDH1 was assessed by immunohistochemistry. ALDH1 staining was further characterized by its presence in stromal versus epithelial and/or tumor components of tissue. RESULTS: A total of 173 women contributed to this study: 69 with benign breast conditions, mean age 24 years, and 104 with breast cancer, mean age 49 years. The proportion of benign breast conditions expressing stromal ALDH1 (n = 40, 58%) was significantly higher than those with cancer (n = 44, 42.3%) (P = .043). Among the cancers, TNBC had the highest prevalence of ALDH1 expression, either in stroma or in epithelial cells. More than 2-fold higher likelihood of ALDH1 expression was observed in TNBC cases compared with other breast cancer subtypes (odds ratio = 2.38, 95% confidence interval 1.03-5.52, P = .042). CONCLUSIONS: ALDH1 expression was higher in stromal components of benign compared with cancerous lesions. Of the ER-, PR-, and HER2-defined subtypes of breast cancer, expression of ALDH1 was highest in TNBC. Cancer 2013. © 2012 American Cancer Society.

Background: Population-based incidence rates of breast cancer (BC) that does not express the estrogen receptor (ER), progesterone receptor (PR) or overexpress the human epidermal growth factor 2 HER2/ neu (triple negative breast cancer, TNBC) are higher among Africans compared with white women. However the underlying biologic and genetic differences among different ethnicities are poorly understood and there are currently very few ethnically diverse BC models available for identifying new therapeutic options. Aim: Establish an international collaboration to: i, characterize African breast tumors ii, create models for studying these tumors and iii, identify biomarkers for early detection and treatment personalization. Methods: We have collected tumors from 154 white Americans WA, 76 African Americans, AA, 190 Ethiopians, Eth, and 286 Ghanaian (Gh) BC patients. We then established a unique resource of patient derived xenografts (PDX) from these tumors. The PDXs were then fully characterized using whole exome and RNA sequencing for the primary tumor, matched normal DNA, and corresponding low passage PDXs. Using immunohistochemistry, we evaluated the ER, PR, HER2/ neu, androgen receptor (AR), and ALDH1 (cancer stem cell marker) expression among these tumors. Based on biomarker expression the PDXs were then tested against a panel of IND drugs, either alone or in combinations, in an ex vivo organoid culture system to discover potential new therapeutic options. Results: Mean age at BC diagnosis was 43; 49; 60; and 57 years for the Eth; Gh; AA; and WA patients, respectively. The proportion of TNBC was significantly higher for the AA and Gh patients (41% and 54%, respectively) compared with the WA and Eth patients (23% and 15%, respectively); P < 0.001. Significant differences were observed for distribution of AR positivity, which was 71%; 55%; 42% and 50% for the WA; AA; Gh; and Eth cases, respectively ( P = 0.008). The Gh breast tumors exhibited the highest number of loss of function and missense mutations that are likely to impact therapy with a high frequency of P53, APC, and FGFR mutations. These mutations were maintained in the corresponding PDXs that were developed, and were thus used as biomarkers for drug screening. These tumors exhibited a gene expression signature based on the ethnicity of the patients with 2385 genes differentially expressed between Gh and AA, 1573 between AA and CA and 1317 between GH and CA. Results from our ongoing drug screening and biomarker identification will be available soon. Conclusions: Establishing the molecular and genetic platform of aggressive breast cancers occurring in women with African ancestry will help in identifying biomarkers for early cancer detection and targeted treatment stratification for optimum patient outcome. The availability of tumor models based on tumors from diverse African populations is the important missing pieces that have to be incorporated into current drug discovery efforts.

e13114Background: 80% of breast cancers - BC are basal; aggressive, and negative for ER, PR and HER2 over expression, termed triple negative - TNBC. In the US, the incidence rate of TNBC is two-fol...

1101 Background: Population-based incidence rates of breast cancers that are negative for estrogen receptor (ER), progesterone receptor (PR), and HER2/ neu(triple negative breast cancer {TNBC}) are higher among African American (AA) compared to White American (WA) women. Several studies show higher TNBC frequency among selected populations of African patients. The colonial-era trans-Atlantic slave trade resulted in shared West African ancestry between contemporary AA and Ghanaian (Gh) populations. The extent to which TNBC susceptibility is related to East African versus West African ancestry, and whether these associations extend to expression of other biomarkers such as Androgen Receptor (AR) and mammary stem cell marker ALDH1 is unknown. Methods: We used immunohistochemistry to assess ER, PR, HER2/ neu, AR and ALDH1 among WA (n = 153); AA (n = 76); Ethiopian (Eth)/East African (n = 90) and (Gh)/West African (n = 286) breast cancers through an IRB-approved international research program. Results: Mean age at breast cancer diagnosis was 43; 49; 60; and 57 years for the Eth; Gh; AA; and WA patients, respectively. Frequency of TNBC was significantly higher for AA and Gh patients (54% and 41%, respectively) compared to WA and Eth patients (23% and 15%, respectively); p < 0.001. These associations were unchanged when limited to patients age 50 and younger (47% and 49% for AA and Gh, respectively; versus 18% and 16% for WA and Eth, respectively); p < 0.001. Frequency of ALDH1 positivity was also higher for tumors from AA and Gh patients (32% and 36%, respectively) compared to those from WA and Eth patients (23% and 17%, respectively); p = 0.007. Significant differences were observed for distribution of AR positivity, which was 71%; 55%; 42% and 50% for the WA; AA; Gh; and Eth cases, respectively (p = 0.008). Conclusions: We found a correlation between extent of African ancestry and risk of particular BC phenotypes. West African ancestry was associated with increased risk of TNBC and breast cancers that are positive for ALDH1. Future studies of hereditary TNBC susceptibility among women with African ancestry are warranted.

In our communities there are large numbers of longstanding external hernias that remain untreated. This paper describes the epidemiological characteristics of these hernias. The data is expected to provide guidelines for sustained national and international efforts to reduce the burden of hernia by performing large-scale elective hernia repairs.Between January 1998 and December 2007, a simple pro-forma was designed and used to record, in a prospective manner, the age, sex of patient and anatomical site of all external hernias seen and operated on both as emergencies and non-emergencies. These were patients who presented to a single general and paediatric surgeon at the Komfo Anokye Teaching Hospital in Kumasi, Ghana.A total of 2,506 patients were studied, of which 1,930 were male and 576 female, giving a male:female ratio of 3.4:1. Inguinal hernia was seen in 1,766 patients: 1,613 males and 153 females, a male:female ratio of 10.5:1. Children 4 years old or younger accounted for 20.9% of inguinal hernias. Femoral hernia was seen in 79 patients: 70 females and 9 males. These groin hernias were diagnosed in 1,845 patients, accounting for 73.6% of all patients. Incisional hernia was diagnosed in 380 patients (15.2%): 179 males and 201 females-a male:female ratio of 1:1.1. These two hernia types (groin and incisional) were seen in 2,225 patients, representing 88.8% of all the patients studied. All other hernias studied, including para-umbilical, umbilical and epigastric, were seen in 281 patients, representing 11.2% of the hernias studied.The epidemiology of external hernias seen and treated in our hospital is no different from that of hernias in other communities. Sustained efforts at elective repair will reduce the vast numbers of untreated accumulated hernias in our communities and thus prevent unnecessary morbidity and mortality.

596 Background: Breast cancer (BC) is now emerging as the most commonly diagnosed cancer among women in sub-Saharan Africa, surpassing cervical cancer. Although its incidence is relatively low in w...

Background Data on cancers is a challenge in most developing countries. Population-based cancer registries are also not common in developing countries despite the usefulness of such registries in informing cancer prevention and control programmes. The availability of population-based data on cancers in Africa varies across different countries. In Ghana, data and research on cancer have focussed on specific cancers and have been hospital-based with no reference population. The Kumasi Cancer Registry was established as the first population-based cancer registry in Ghana in 2012 to provide information on cancer cases seen in the city of Kumasi. Methods This paper reviews data from the Kumasi Cancer Registry for the year 2012. The reference geographic area for the registry is the city of Kumasi as designated by the 2010 Ghana Population and Housing Census. Data was from all clinical departments of the Komfo Anokye Teaching Hospital, Pathology Laboratory Results, Death Certificates and the Kumasi South Regional Hospital. Data was abstracted and entered into Canreg 5 database. Analysis was conducted using Canreg 5, Microsoft Excel and Epi Info Version 7.1.2.0. Results The majority of cancers were recorded among females accounting for 69.6% of all cases. The mean age at diagnosis for all cases was 51.6 years. Among males, the mean age at diagnosis was 48.4 compared with 53.0 years for females. The commonest cancers among males were cancers of the Liver (21.1%), Prostate (13.2%), Lung (5.3%) and Stomach (5.3%). Among females, the commonest cancers were cancers of the Breast (33.9%), Cervix (29.4%), Ovary (11.3%) and Endometrium (4.5%). Histology of the primary tumour was the basis of diagnosis in 74% of cases with clinical and other investigations accounting for 17% and 9% respectively. The estimated cancer incidence Age Adjusted Standardised Rate for males was 10.9/100,000 and 22.4/100, 000 for females. Conclusion This first attempt at population-based cancer registration in Ghana indicates that such registries are feasible in resource limited settings as ours. Strengthening Public Health Surveillance and establishing more Population-based Cancer Registries will help improve data quality and national efforts at cancer prevention and control in Ghana.