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

A novel role for KIFC1-MYH9 interaction in triple-negative breast cancer aggressiveness and racial disparity

African American (AA) women are twice as likely to develop triple-negative breast cancer (TNBC) as women of European descent. Additionally, AA women with TNBC present a much more aggressive disease course than their European American (EA) counterparts. Thus, there is an unmet clinical need to identify race-specific biomarkers and improve survival outcomes in AA patients with TNBC. The minus-end directed microtubule motor protein kinesin family member C1 (KIFC1) promotes centrosome clustering and chromosomal instability and is often overexpressed in TNBC. Previous findings suggest that KIFC1 plays a role in cell proliferation and migration in TNBC cells from AAs and that the levels of nuclear KIFC1 (nKIFC1) are particularly high in AA patients with TNBC. The nuclear localization of KIFC1 in interphase may underlie its previously unrecognized race-specific association. In this study, we found that in TNBC cells derived from AAs, nKIFC1 interacted with the tumor suppressor myosin heavy chain 9 (MYH9) over EA cells. Treatment of AA TNBC cells with commercial inhibitors of KIFC1 and MYH9 disrupted the interaction between KIFC1 and MYH9. To characterize the racial differences in the KIFC1-MYH9-MYC axis in TNBC, we established homozygous KIFC1 knockout (KO) TNBC cell lines. KIFC1 KO significantly inhibited proliferation, migration, and invasion in AA TNBC cells but not in EA TNBC cells. RNA sequencing analysis showed significant downregulation of genes involved in cell migration, invasion, and metastasis upon KIFC1 KO in TNBC cell lines from AAs compared to those from EAs. These data indicate that mechanistically, the role of nKIFC1 in driving TNBC progression and metastasis is stronger in AA patients than in EA patients, and that KIFC1 may be a critical therapeutic target for AA patients with TNBC.

Clinical outcomes of chemotherapy in cancer patients with different ethnicities

BACKGROUND

Choosing the most effective chemotherapeutic agent with safest side effect profile is a common challenge in cancer treatment. Although there are standardized chemotherapy protocols in place, protocol changes made after extensive clinical trials demonstrate significant improvement in the efficacy and tolerability of certain drugs. The pharmacokinetics, pharmacodynamics, and tolerance of anti-cancer medications are all highly individualized. A driving force behind these differences lies within a person's genetic makeup.

RECENT FINDINGS

Pharmacogenomics, the study of how an individual's genes impact the processing and action of a drug, can optimize drug responsiveness and reduce toxicities by creating a customized medication regimen. However, these differences are rarely considered in the initial determination of standardized chemotherapeutic protocols and treatment algorithms. Because pharmacoethnicity is influenced by both genetic and nongenetic variables, clinical data highlighting disparities in the frequency of polymorphisms between different ethnicities is steadily growing.  Recent data suggests that ethnic variations in the expression of allelic variants may result in different pharmacokinetic properties of the anti-cancer medication. In this article, the clinical outcomes of various chemotherapy classes in patients of different ethnicities were reviewed.

CONCLUSION

Genetic and nongenetic variables contribute to the interindividual variability in response to chemotherapeutic drugs. Considering pharmacoethnicity in the initial determination of standard chemotherapeutic protocols and treatment algorithms can lead to better clinical outcomes of patients of different ethnicities.

The coming decade in precision oncology: six riddles

High-throughput methods to investigate tumour omic landscapes have quickly catapulted cancer specialists into the precision oncology era. The singular lesson of precision oncology might be that, for it to be precise, treatment must be personalized, as each cancer's complex molecular and immune landscape differs from patient to patient. Transformative therapies include those that are targeted at the sequelae of molecular abnormalities or at immune mechanisms, and, increasingly, pathways previously thought to be undruggable have become druggable. Critical to applying precision medicine is the concept that the right combination of drugs must be chosen for each patient and used at the right stage of the disease. Multiple puzzles remain that complicate therapy choice, including evidence that deleterious mutations are common in normal tissues and non-malignant conditions. The host's role is also likely to be key in determining treatment response, especially for immunotherapy. Indeed, maximizing the impact of immunotherapy will require omic analyses to match the right immune-targeted drugs to the individualized patient and tumour setting. In this Perspective, we discuss six key riddles that must be solved to optimize the application of precision oncology to otherwise lethal malignancies.

Quantification of Women Who Could Benefit from Hormone Therapy after Endometrial Cancer Treatment: An Analysis of SEER Data

Our primary aim was to estimate the magnitude of stage I endometrial cancer (EC) survivors that could benefit from hormonal therapy (HT). Our secondary aims were to assess EC incidence in women below 50 and below 60 over the years, and analyze the overall survival and any influencing factors. We analyzed the endometrioid EC data from the Surveillance, Epidemiology, and End Results (SEER) program according to women's age, tumor stage, and grade. We analyzed the proportions of EC survivors below 50 and below 60 years of age and stratified those age groups by race. For age distribution and survival analysis SEER, 18 registries' research data (2000-2018) were analyzed. We analyzed the SEER 12 registries' research data (1992-2019) for incidence time trends. Our investigation found a 14% and 40% cumulative prevalence of stage I EC that occurs in women below 50 or 60 years, respectively. EC's prevalence has progressively risen in recent decades, but cancer-specific mortality remains low. The increasing number of women affected by EC in premenopause or early postmenopause face an 18 years-survival rate of 96.86% and 95.73%, respectively. A significant proportion of low-grade EC survivors can potentially benefit from HT treatment, and this requires awareness of other aspects of their health or quality of life, in addition to cancer treatments.

Reproductive factors and the risk of breast cancer among Nigerian women by age and oestrogen receptor status

PURPOSE OF THE STUDY

The aim of the study was to investigate the association between reproductive factors and breast cancer risk in Nigeria. This has not been widely investigated in sub-Saharan Africa.

METHODS

We conducted a hospital-based case-control study involving participants from five hospitals in Lagos and Abuja. Women were interviewed in-person between October 2016 and May 2017 using a semi-structured questionnaire. We collected data on parity, breastfeeding, age at first and last birth, age at menarche, oral contraceptive use and history of abortion. The data were analysed using multivariable logistic regression adjusting for relevant confounders.

RESULTS

Every additional 6 months of breastfeeding over a lifetime reduced breast cancer odds by: 7% (95% CI: 1%, 12%) in all women, 15% (95% CI: 5%, 24%) in women < 50 years, and 8% (95% CI: 0%, 12%, p for trend = 0.043) in oestrogen receptor negative (ER-) cases. Each additional 1-year delay before the first full-term pregnancy increased oestrogen receptor positive breast cancer odds by 9% (95% CI: 2%, 17%). Each additional 1-year delay before the last full-term pregnancy increased breast cancer odds by: 7% (95% CI: 2%, 12%) in all women, 12% (95% CI: 4%, 21%) in ER- breast cancer patients, and 14% (95% CI: 4%, 25%) in triple negative breast cancer patients. Other reproductive factors did not significantly increased breast cancer odds.

CONCLUSION

While advanced age at first and last full-term pregnancies increased breast cancer odds, breastfeeding reduced it. These associations varied by age and oestrogen receptor status. Improved breastfeeding practices and timely births should be promoted in Nigeria.

Haplotypes of single cancer driver genes and their local ancestry in a highly admixed long-lived population of Northeast Brazil

Admixed populations have not been examined in detail in cancer genetic studies. Here, we inferred the local ancestry of cancer-associated single nucleotide polymorphisms (SNPs) and haplotypes of a highly admixed Brazilian population. SNP array was used to genotype 73 unrelated individuals aged 80-102 years. Local ancestry inference was performed by merging genotyped regions with phase three data from the 1000 Genomes Project Consortium using RFmix. The average ancestry tract length was 9.12-81.71 megabases. Strong linkage disequilibrium was detected in 48 haplotypes containing 35 SNPs in 10 cancer driver genes. All together, 19 risk and eight protective alleles were identified in 23 out of 48 haplotypes. Homozygous individuals were mainly of European ancestry, whereas heterozygotes had at least one Native American and one African ancestry tract. Native-American ancestry for homozygous individuals with risk alleles for HNF1B, CDH1, and BRCA1 was inferred for the first time. Results indicated that analysis of SNP polymorphism in the present admixed population has a high potential to identify new ancestry-associated alleles and haplotypes that modify cancer susceptibility differentially in distinct human populations. Future case-control studies with populations with a complex history of admixture could help elucidate ancestry-associated biological differences in cancer incidence and therapeutic outcomes.

Metabolic Syndrome and Risk of Breast Cancer by Molecular Subtype: Analysis of the MEND Study

Metabolic syndrome is a cluster of biological irregularities that is a known risk factor for cardiovascular disease, stroke, and diabetes. In a case-control study of 555 West African women, we observed that metabolic syndrome was strongly associated with breast cancer and the aggressive triple-negative molecular subtype, highlighting a need for clinical and lifestyle interventions targeting metabolic syndrome to reduce breast cancer risk in this population.

Few Losses to Follow-up in a Sub-Saharan African Cancer Cohort via Active Mobile Health Follow-up

Accurate survival estimates are needed for guiding cancer control efforts in sub-Saharan Africa, but previous studies have been hampered by unknown biases due to excessive loss to follow-up (LTFU). In the African Breast Cancer-Disparities in Outcomes Study, a prospective breast cancer cohort study, we implemented active mobile health follow-up, telephoning each woman or her next-of-kin (NOK) trimonthly on her mobile phone to update information on her vital status. Dates of every contact with women/NOK were analyzed from diagnosis in 2014-2017 to the earliest of September 1, 2018, death, or 3 years postdiagnosis. The cumulative incidence of being LTFU was calculated considering deaths as competing events. In all, 1,490 women were followed for a median of 24.2 (interquartile range (IQR), 14.2-34.5) months, corresponding to 8,529 successful contacts (77% of total contacts) with the women/NOK. Median time between successful contacts was 3.0 (IQR, 3.0-3.7) months. In all, 71 women (5.3%) were LTFU at 3 years: 0.8% in Nigeria, 2.2% in Namibia, and 5.6% in Uganda. Because of temporary discontinuity of active follow-up, 20.3% of women were LTFU after 2 years in Zambia. The median time to study notification of a death was 9.1 (IQR, 3.9-14.0) weeks. Although the present study was not a randomized controlled trial, in this cancer cohort with active mobile health follow-up, LTFU was much lower than in previous studies and enabled estimation of up-to-date and reliable cancer survival.

Distribution of Breast Cancer Subtypes Among Nigerian Women and Correlation to the Risk Factors and Clinicopathological Characteristics

Background

Breast cancer in African women differs from the Caucasian. Understanding the profile of Nigerian women with breast cancer will help with preventive measures and treatment. This study focused on the clinico-pathological characteristics, with risk factors of breast cancer patients in Nigeria.

Methods

Newly diagnosed female patients with breast cancer were assessed over 12 months. Patients were reviewed using a predesigned proforma which focused on socio-demographic information, clinical information, risk factors and tumor biology.

Results

A total of 251 women were identified; their mean age was 46 years. More than half (62.5%) are premenopausal at presentation, 37.8% with Eastern Cooperative Oncology Group (ECOG) score of 0 and right side (50.2%) as the most common primary site of disease. Less than half of them (43.0%) are estrogen receptor (ER) positive, 27.9% are progesterone receptor (PR) positive, 43.8% and 47.4% are hormone receptor positive and triple negative, respectively. Most patients presented at the latter stage of the disease, stage III (66.9%) and stage IV (18.3%). Only 15.9% are well differentiated and almost all (92.8%) had invasive ductal histological type. Obesity (66.2%) and physical inactivity (41.9%) are the most common risk factors for the disease. A significant relationship was found between immunohistochemistry status and family history of breast cancer, tumor site, previous breast surgery, previous lump and alcohol intake.

Conclusion

Findings from this study showed that Nigerian breast cancer patients differ from their counterparts in the high human development index (H-HDI) countries in terms of the patients and disease characteristics. In view of this, prevention and treatment options should consider this uniqueness to ensure better outcome.

Distinct temporal trends in breast cancer incidence from 1997 to 2016 by molecular subtypes: a population-based study of Scottish cancer registry data

BACKGROUND

We describe temporal trends in breast cancer incidence by molecular subtypes in Scotland because public health prevention programmes, diagnostic and therapeutic services are shaped by differences in tumour biology.

METHODS

Population-based cancer registry data on 72,217 women diagnosed with incident primary breast cancer from 1997 to 2016 were analysed. Age-standardised rates (ASR) and age-specific incidence were estimated by tumour subtype after imputing the 8% of missing oestrogen receptor (ER) status. Joinpoint regression and age-period-cohort models were used to assess whether significant differences were observed in incidence trends by ER status.

RESULTS

Overall, ER-positive tumour incidence increased by 0.4%/year (95% confidence interval (CI): -0.1, 1.0). Among routinely screened women aged 50-69 years, we observed an increase in ASR from 1997 to 2011 (1.6%/year, 95% CI: 1.2-2.1). ER-negative tumour incidence decreased among all ages by 2.5%/year (95% CI: -3.9 to -1.1%) over the study period. Compared with the 1941-1959 birth cohort, women born in 1912-1940 had lower incidence rate ratios (IRR) for ER+ tumours and women born in 1960-1986 had lower IRR for ER- tumours.

CONCLUSIONS

Future incidence and survival reporting should be monitored by molecular subtypes to inform clinical planning and cancer control programmes.

Does race predict survival for women with invasive breast cancer?

BACKGROUND

Black women with breast cancer have lower survival rates and higher recurrence rates in comparison with white women. This study compared treatment and survival outcomes for black and white women at a highly specialized tertiary care cancer center.

METHODS

An institutional review board-approved, retrospective institutional database review was performed to identify all black women treated for invasive breast cancer between 2005 and 2010. Women with a prior history of breast cancer, stage IV cancer, or bilateral breast cancer were excluded. White women had similar exclusion criteria applied and were then matched to black women 1:1 by age and diagnosis year. Clinicopathologic and treatment variables were compared by race. Kaplan-Meier methodology was used to estimate overall survival (OS) and disease-free survival (DFS); a multivariable analysis was conducted with Cox regression models.

RESULTS

The study group consisted of 1332 women (666 black). The median tumor size was larger in black women (1.6 vs 1.3 cm; P < .001). Black women had more nodal disease (41.1% vs 32%; P < .001) and had tumors that were more frequently an estrogen receptor-negative (32.9% vs 15%; P < .001), progesterone receptor-negative (47.1% vs 30.2%; P < .001), or triple-negative (TN) subtype (24% vs 8.9%; P < .001) in comparison with white women. Black women also had inferior DFS and OS; race was not an independent prognostic indicator in the multivariable analysis.

CONCLUSIONS

Black women had more advanced disease and adverse prognostic indicators at diagnosis, but race was not an independent predictor of outcome. Black women were significantly more likely to have TN breast cancer. Further research is necessary to understand the differences in tumor biology associated with race.

Survival Analysis of Cancer Patients in North Eastern Nigeria from 2004 - 2017 - A Kaplan - Meier Method

BACKGROUND:

Cancer is a deadly malignant disease and is prevalent in Sub Saharan Africa. The North East part of Nigeria in particular and the country, in general, are struggling to cope with the increasing burden of cancer and other communicable and non-communicable diseases. The situation is worsened by the ongoing insurgency and terrorist activities in the area.

AIM:

The aim of this paper is to present the research findings from a cohort study aimed at the analysis of the estimation of the survivorship time of the real data of cancer patients in the North-eastern part of Nigeria and to establish if the insurgency in the region has contributed negatively to the life expectancy of its inhabitants.

MATERIAL AND METHODS:

The record of 1,090 patients from medical records departments of the University of Maiduguri Teaching Hospital (UMTH), located in Maiduguri, the capital city of Borno State in northeast Nigeria was obtained. The record showed patients that were diagnosed and died of one type of cancer or the other from 2004 to 2017. All the cancer cases included in the present study were grouped into sex, age, marital status, occupation, date admitted and date of death/discharge. Descriptive statistics and Kaplan-Meier method were used to analyse the data using SPSS version 23 while Microsoft EXCEL and Minitab 16.0 were used for data cleansing and organisation.

RESULTS:

Of the 1,090 patients analysed, 920 (84.40%) experienced the event, i.e. death, while 170 (15.60%) patients were censored. The data were analysed based on the ages and sex of the patients. 50.20% of the patients were of ages 21-50 years. The proportions of patients in this age bracket surviving past 7 days are 75%, while those between ages 80 years and above is 12 days. Others are of survival time of 5 days (ages 0-20 years) and 7 days (51-79 years). Using sex, 75% of the patients’ survival time is 7 days in the case of male and 6 days for females. It is safe to say that the survival time for cancer patients of the university the Maiduguri is 6 days and the result reflects the Northeastern part of Nigeria. This is because the hospital is one of few tertiary healthcare facilities in that area and consequently, cancer cases are often referred there.

CONCLUSION:

Cancer incidence is high, and the probability of survival reduces as the survival time increases. This is a dire situation in need of urgent intervention from the government, groups and individuals to tackle the scourge of cancer, thereby improving on the life expectancy battered by the ongoing Boko Haram insurgency in that region.

Checkpoint Kinase 1 Expression Predicts Poor Prognosis in Nigerian Breast Cancer Patients

BACKGROUND

Checkpoint kinase 1 (CHEK1), a DNA damage sensor and cell death pathway stimulator, is regarded as an oncogene in tumours, where its activities are considered essential for tumourigenesis and the survival of cancer cells treated with chemotherapy and radiotherapy. In breast cancer, CHEK1 expression has been associated with an aggressive tumour phenotype, the triple-negative breast cancer subtype, an aberrant response to tamoxifen, and poor prognosis. However, the relevance of CHEK1 expression has, hitherto, not been investigated in an indigenous African population. We therefore aimed to investigate the clinicopathological, biological, and prognostic significance of CHEK1 expression in a cohort of Nigerian breast cancer cases.

MATERIAL AND METHODS

Tissue microarrays of 207 Nigerian breast cancer cases were tested for CHEK1 expression using immunohistochemistry. The clinicopathological, molecular, and prognostic characteristics of CHEK1-positive tumours were determined using the Chi-squared test and Kaplan-Meier and Cox regression analyses in SPSS Version 16.

RESULTS

Nuclear expression of CHEK1 was present in 61% of breast tumours and was associated with tumour size, triple-negative cancer, basal-like phenotype, the epithelial-mesenchymal transition, p53 over-expression, DNA homologous repair pathway dysfunction, and poor prognosis.

CONCLUSIONS

The rate expression of CHEK1 is high in Nigerian breast cancer cases and is associated with an aggressive phenotype and poor prognosis.

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.

Breast cancer survival in Soweto, Johannesburg, South Africa: A receptor-defined cohort of women diagnosed from 2009 to 11

BACKGROUND

South Africa's public healthcare system is better equipped to manage breast cancer than most other SSA countries, but survival rates are unknown.

METHODS

A historical cohort of 602 women newly diagnosed with invasive breast carcinoma during 2009-2011 at Chris Hani Baragwanath Academic Hospital, Soweto, Johannesburg, was followed using health systems data to December 2014. 'Overall survival' time was defined from diagnosis to death or terminal illness. Cox regression was used to estimate hazard ratios (HR) associated with woman and tumour characteristics.

RESULTS

During a median 2.1 years follow-up (IQR 0.5-3.8), 149 women died or were classified terminally ill; 287 were lost-to-follow-up. 3-year survival was 84% for early stage (I/II) and 56% for late stage (III/IV) tumours (late v early: HR 2.8 (95% confidence interval (CI): 1.9-4.1), however the 42% cumulative losses to follow-up over this period were greater for late stage, half of which occurred within 6 months of diagnosis. After mutual adjustment for stage, grade, age, receptor subtype and HIV status, lower survival was also associated with triple negative (HR 3.1 (95% CI: 1.9-5.0)) and HER2-enriched (2.5 (95% CI: 1.4-4.5)) compared to ER/PR+ HER2- tumours, but not with age or HIV-infection (1.4 (95% CI: 0.8, 2.3)).

CONCLUSION

In this South African cohort, breast cancer survival is suboptimal, but was better for early stage and hormone receptor-positive tumours. Efforts to reduce clinic losses in the immediate post-diagnosis period, in addition to early presentation and accelerated diagnosis and treatment, are needed to prevent breast cancer deaths, and survival improvements need to be monitored using prospective studies with active follow-up.

Kaiso is highly expressed in TNBC tissues of women of African ancestry compared to Caucasian women

Purpose

Triple-negative breast cancer (TNBC) is most prevalent in young women of African ancestry (WAA) compared to women of other ethnicities. Recent studies found a correlation between high expression of the transcription factor Kaiso, TNBC aggressiveness, and ethnicity. However, little is known about Kaiso expression and localization patterns in TNBC tissues of WAA. Herein, we analyze Kaiso expression patterns in TNBC tissues of African (Nigerian), Caribbean (Barbados), African American (AA), and Caucasian American (CA) women.

Methods

Formalin-fixed and paraffin embedded (FFPE) TNBC tissue blocks from Nigeria and Barbados were utilized to construct a Nigerian/Barbadian tissue microarray (NB-TMA). This NB-TMA and a commercially available TMA comprising AA and CA TNBC tissues (AA-CA-YTMA) were subjected to immunohistochemistry to assess Kaiso expression and subcellular localization patterns, and correlate Kaiso expression with TNBC clinical features.

Results

Nigerian and Barbadian women in our study were diagnosed with TNBC at a younger age than AA and CA women. Nuclear and cytoplasmic Kaiso expression was observed in all tissues analyzed. Analysis of Kaiso expression in the NB-TMA and AA-CA-YTMA revealed that nuclear Kaiso H scores were significantly higher in Nigerian, Barbadian, and AA women compared with CA women. However, there was no statistically significant difference in nuclear Kaiso expression between Nigerian versus Barbadian women, or Barbadian versus AA women.

Conclusions

High levels of nuclear Kaiso expression were detected in patients with a higher degree of African heritage compared to their Caucasian counterparts, suggesting a role for Kaiso in TNBC racial disparity.

Electronic supplementary material

The online version of this article (doi:10.1007/s10552-017-0955-2) contains supplementary material, which is available to authorized users.

Breast cancer in Angola, molecular subtypes: a first glance

Purpose

The aim of this study was to investigate the breast cancer (BC) molecular subtypes according to its surrogate immunohistochemistry (IHC) markers. We conducted a preliminary study, to correlate the clinical pathological profiles and molecular subtypes of breast cancer in Luanda, Angola.

Methods

From January 2011 to 30 December 2014, 140 consecutive cases of microscopically confirmed invasive breast carcinoma were classified regarding histology and IHC (ER, PR, HER2, and Ki-67). Surrogate molecular subtypes were classified according to ESMO recommendations.

Results

All patients were female; the median age was 47 years (24–84 years). Invasive carcinoma NST was the most common type (91.4%) and grade 2 was prevalent (70.7%). Most tumours were locally advanced (stage III – 65% and stage IV – 3.6%). In 140 studied cases, 74 (52.8%) malignancies were hormone receptor positive; 25.7% were luminal A like, 19.3% luminal B and HER2 negative like, 7.9% luminal B and HER2-positive like, 15.7% HER2 positive, and 31.4% were triple negative.

Conclusion

Women’s BC in Luanda-Angola is diagnosed at a young age and at an advanced stage. The two predominant molecular subtypes are HR positive and triple negative. The percentage of HER2-positive BC cases was high. Determining the molecular subtype using surrogate IHC markers has important treatment and prognostic implications for Angolan women with BC. There is an urgent need to study a prospective BC series in order to confirm the present results.

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

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

Clinicopathological and molecular characteristics of Ku 70/80 expression in Nigerian breast cancer and its potential therapeutic implications

Ku 70/80 is a regulator of the Non-Homologous End Joining (NHEJ) roles in clinicopathological features, and has prognostic significance in breast cancer (BC) in Caucasian populations. However, its significance in the Nigerian BC population, which is characterized by a higher rate of the triple-negative and basal phenotype, p53 mutation rate and BRCA1 deficiency, still needs to be investigated. We hypothesize that Ku70/80 expression shows adverse expression in Nigerian BC and, furthermore, that it is likely to have a therapeutic implication for Black BC management. This study investigated the biological, clinicopathological and prognostic significance of Ku 70/80 expression in a BC cohort from a Nigerian population. Ku 70/80 expression was determined in 188 well-characterized formalin-fixed, paraffin-embedded (FFPE) BC samples using tissue microarray and immunohistochemistry. Ku 70/80 expression was correlated with clinicopathological, molecular and prognostic characteristics of patients. Ku 70/80 was expressed in 113 (60.1%) tumors, and was positively associated with metastatic disease, triple-negative and basal phenotype, BRCA1 down regulators (MTA-1 and ID4), p-cadherin, PI3KCA and p53 expression. It inversely correlated with BRCA1, BRCA2, BARD1 and p27. Ku 70/80 was predictive of breast cancer-specific survival in multivariate analysis, but not of disease-free interval. This study demonstrated that Ku 70/80 expression is associated with triple negativity and down-regulation of the homologous recombination pathway of DNA repair. Therefore, the development of novel drugs to target KU70/80 may improve the patients' outcome in the treatment of Black BC.

Histological Features and Tissue Microarray Taxonomy of Nigerian Breast Cancer Reveal Predominance of the High-Grade Triple-Negative Phenotype

INTRODUCTION

Little is known about the biology, molecular profile and hence optimal treatment of African Nigerian breast cancer. The aim of this work, therefore, was to characterize the histology and molecular profile of Nigerian breast cancer.

METHODS

Breast carcinomas from women at 6 centres of similar tribal origin in Nigeria were reviewed and assembled into tissue microarrays (TMAs), and sections were stained for hormone receptors, i.e. estrogen receptor (ER)α, ERβ1, ERβ progesterone receptor (PR) and androgen receptor, cyclin D, HER2, Ki67 and cytokeratins (CKs), i.e. CK5/6 and CK14 (basal) and CK18 and 19 (luminal).

RESULTS

A total of 835 tumours were analysed. The mean age at diagnosis was 48.62 ± 12.41 years. The most common histological subtype was ductal NST (no-special-type) carcinoma (87.3%). Over 90% of the tumours were grade 2 or 3. The predominant molecular phenotype was the non-basal, triple-negative type (47.65%) followed by the HER2-positive group (19.6%). The percentage of ER-, PR- and HER2-positive tumours was 22.4, 18.9 and 18.8%, respectively.

CONCLUSION

Nigerian breast cancer predominantly has a high-grade, triple-negative profile. It occurs at a younger age and bears similarities at the molecular level to pre-menopausal breast cancer in white women, with remarkably lower levels of ERβ expression. The early presentation and histological and molecular phenotype may explain the poor prognosis, and tailoring treatment strategies to target this unique profile are required.

Cancer Genomics: Diversity and Disparity Across Ethnicity and Geography

Ethnic and geographic differences in cancer incidence, prognosis, and treatment outcomes can be attributed to diversity in the inherited (germline) and somatic genome. Although international large-scale sequencing efforts are beginning to unravel the genomic underpinnings of cancer traits, much remains to be known about the underlying mechanisms and determinants of genomic diversity. Carcinogenesis is a dynamic, complex phenomenon representing the interplay between genetic and environmental factors that results in divergent phenotypes across ethnicities and geography. For example, compared with whites, there is a higher incidence of prostate cancer among Africans and African Americans, and the disease is generally more aggressive and fatal. Genome-wide association studies have identified germline susceptibility loci that may account for differences between the African and non-African patients, but the lack of availability of appropriate cohorts for replication studies and the incomplete understanding of genomic architecture across populations pose major limitations. We further discuss the transformative potential of routine diagnostic evaluation for actionable somatic alterations, using lung cancer as an example, highlighting implications of population disparities, current hurdles in implementation, and the far-reaching potential of clinical genomics in enhancing cancer prevention, diagnosis, and treatment. As we enter the era of precision cancer medicine, a concerted multinational effort is key to addressing population and genomic diversity as well as overcoming barriers and geographical disparities in research and health care delivery.

Prognostic features of breast cancer differ between women in the Democratic Republic of Congo and Belgium

OBJECTIVES

Compared to European women, breast cancers in African women present at a younger age, with a higher tumor grade and are more often estrogen receptor (ER)/progesterone receptor (PR) negative. We here investigate the histopathological and immunohistochemical characteristics (ER, PR and human epidermal growth receptor 2 (HER2)) and the proportion of triple negative (Tneg) invasive breast cancers from an unselected series of patients diagnosed in Kinshasa, and compare them to a population of Caucasian women with a palpable breast cancer.

MATERIALS AND METHODS

From 2010 till 2013, during the first breast cancer awareness campaign, organized in Kinshasa, 87 patients were diagnosed with invasive breast cancer. Diagnose was based on core biopsy. The control group consisted of Caucasian women (University Hospitals of Leuven, Belgium) with a palpable mass, diagnosed between 2000 till 2009, treated with surgery of which the histopathological and immunohistochemical characteristics were collected on excision specimens. Each patient in the Kinshasa group was matched based on age and tumor size to one or more patients of the Leuven database. Differences between both groups with respect to hormone receptors (ER, PR, HER2, Tneg) or grade are presented as relative risks (RR). The analysis is based on a log-binomial model accounting for clustering through matching by a random intercept for cluster. Differences between both groups with respect to hormone receptors correcting for grade is performed by the inclusion of grade as a covariate in the model.

RESULTS

After adjusting for age, tumor volume and tumor grade, ER was more frequently negative (RR = 0.71, p < 0.001), with a trend in the same direction for PR (RR = 0.87, p = 0.057), and HER2 more often positive (RR = 1.60, p = 0.015) compared to the group from the University Hospitals of Leuven. There was no difference in the proportion of breast cancers being triple negative. Sub-analysis showed that the higher HER2 positive rate was only observed in older patients (≥50y: RR = 2.07, p = 0.007) whereas no difference in HER2 positive rate was found in younger patients (<50y: RR = 1.30, p = 0.358). A higher ER negative rate was observed in both age groups, however more pronounced in older patients (≥50y: RR = 0.64, p = 0.001; <50y: RR = 0.79, p = 0.018).

CONCLUSION

Breast cancer in women of Kinshasa presents at younger age and is more aggressive (more frequently ER negative and HER2 positive) compared to Caucasian women and this is more pronounced in older women (>50y). Only the ER results were concordant with the results of two similar studies (comparing an African with a European group), but were different when compared to studies on African-American women with breast cancer. This information is very important considering the treatment option: as more tumors are ER negative, endocrine therapy cannot be given while chemotherapy is often too expensive.

Differences in biological features of breast cancer between Caucasian (Italian) and African (Tanzanian) populations

Information on hormone receptor and human epidermal growth factor receptor-2 (HER2) expression in breast cancer is acknowledged as mandatory for prognostic stratification and treatment planning. Data on the biological features of African breast cancers are poor. We decided to compare histopathological and biomolecular characteristics (estrogen and progesterone receptor—ER, PgR, and HER2) of Tanzanian and Italian breast cancers. Differences in proliferating index and androgen receptor (AR) expression in triple-negative patients from the two case series were also assessed. Of the 103 consecutive patients seen at the Bugando Medical Center (Mwanza, Tanzania) from 2003 to 2010, who underwent biopsy or surgical resection of primary breast cancer, 69 patients had tissue samples that were evaluable for estrogen receptor (ER), progesterone receptor (PgR), and HER2. Histopathological assessment and biomolecular determinations were performed at the Cancer Institute of Romagna (IRST IRCCS, Meldola, Italy). Caucasian breast cancers were randomly extracted from an electronic database and matched (1:2 ratio) for year of diagnosis and age at diagnosis. Median age of both populations was 51 years (range 27–84). With respect to Caucasian tumors, Tanzanian breast cancers at diagnosis more frequently showed high histological grade (mainly grade 3) (P = 0.03), advanced clinical stage (III or IV) (P\0.001), ER negativity (52.2 %, P\0.001) and high proliferation (P = 0.0002). Triple-negative tumors were over-represented in Tanzanian women. AR was positive in 38.5 and 38 %of triple-negative Tanzanian and Italian breast cancers, respectively. Our results show that histopathological and biomolecular characteristics in Tanzanian and Italian breast cancers differ substantially. The high frequency of poorly differentiated, ER-negative, highly proliferating tumors, together with advanced stage at presentation, could be considered as the main prognostic factors linked to the high mortality rates for breast cancer in the African population.

Breast Evaluation Findings in Calabar, Nigeria

BACKGROUND:  X-ray and sonomammography constitute a significant option in the early detection and management of breast diseases in the developed world. Unfortunately these modalities became available in Nigeria, only in the past few decades.AIM: The aim of this audit is therefore to document the imaging findings, in the past three years in a developing facility in Nigeria relating them with the demograghic features.METHODS: We prospectively studied the x-ray and sonomammography in all patients, presenting over a three year period, for breast evaluation with the hope of discerning the epidemiologic pattern of breast lesions in this environment.RESULTS: One hundred and forty-five females and four males. Median was 38 years (IQR=30-48). The commonest reason for evaluation was screening. Patients that were below 38 years showed no significant difference in frequency and type of lesion compared with patients over 38 years. The commonest breast pattern was fatty replaced. The upper outer quadrant was the commonest site.CONCLUSION: Patients presenting for breast evaluation in Calabar do so for screening mainly. Patients below 38 are nearly equally affected by malignant breast disease as their older counterparts. The commonest breast pattern was fatty replaced. Digital mammography should be available in all tertiary institutions.

Racial comparison of receptor-defined breast cancer in Southern African women: subtype prevalence and age-incidence analysis of nationwide cancer registry data

BACKGROUND

Receptor-defined breast cancer proportions vary across Africa. They have important implications for survival prospects and research priorities.

METHODS

We studied estrogen receptor (ER), progesterone receptor (PR), and HER2 receptor statuses in two multiracial Southern African countries with routine diagnostic immunohistochemistry. A total of 12,361 women with histologically confirmed breast cancer diagnosed at age ≥20 years during (i) 2009-2011 from South Africa's national cancer registry (public sector) and (ii) 2011-2013 from Namibia's only cancer hospital were included. Crude, age, and age + laboratory-adjusted ORs of receptor status were analyzed using logistic regression, and age-incidence curves were analyzed using Poisson regression.

RESULTS

A total of 10,047 (81%) women had known ER status. Ranking of subtypes was consistent across races: ER(+)/PR(+)HER2(-) was most common (race-specific percentage range, 54.6%-64.8%), followed by triple-negative (17.4%-21.9%), ER(+)/PR(+)HER2(+) (9.6%-13.9%), and ER(-)PR(-)HER2(+) (7.8%-10.9%). Percentages in black versus white women were 33.8% [95% confidence (CI), 32.5-35.0] versus 26.0% (24.0-27.9) ER(-); 20.9% (19.7-22.1) versus 17.5% (15.4-19.6) triple-negative; and 10.7% (9.8-11.6) versus 7.8% (6.3-9.3) ER(-)PR(-)HER2(+). Indian/Asian and mixed-ancestry women had intermediate values. Age-incidence curves had similar shapes across races: rates increased by 12.7% per year (12.2-13.1) across ER subtypes under the age of 50 years, and thereafter slowed for ER(+) (1.95%) and plateaued for ER(-) disease (-0.1%).

CONCLUSIONS

ER(+) breast cancer dominates in all Southern African races, but black women have a modest excess of aggressive subtypes.

IMPACT

On the basis of the predominant receptor-defined breast tumors in Southern Africa, improving survival for the growing breast cancer burden should be achievable through earlier diagnosis and appropriate treatment.

Molecular breast cancer subtypes and therapies in a public hospital of northeastern Brazil

BACKGROUND

The frequencies of molecular breast cancer subtypes vary among different human populations. The Northeastern region of Brazil has a mixed population of African, Indigenous and European ancestry. This retrospective study investigated breast cancer subtypes and applied therapies in a public hospital of Northeastern Brazil.

METHODS

Data of 633 patients with invasive breast cancer from 2005 to 2011 were obtained from medical records. Status of hormone receptor (HR), HER2 and Ki67 expression index of 269 out of 633 patients were used to define subtypes of Luminal A and B, HER2 and triple negative (TN) breast cancer. Expression index of Ki67 ≥ 14% was applied to distinguish Luminal A from Luminal B subtypes.

RESULTS

Overall, 185 (68.77%) and 132 (49.07%) patients showed positive hormone receptor (HR+) and positive HER2 (HER2+) tumors. The mean age ranged from 53.33 to 58.25 years for patients with tumors of Luminal B and Luminal A subtypes, respectively (p = 0.0182). In general, 67.39% of patients with TN tumors aged over 50 and 19.57% aged between 31 and 40 years (p = 0.0046). The rate of small tumors (T1: ≤ 2.0 cm) varied from 22.73% to 52.46% for TN and Luminal A subtypes (p = 0.0088). The rate of high graded (G3) tumors was increased for HER2 and TN subtypes (35.29% and 34.28%) compared to Luminal A and Luminal B subtypes (3.92% and 12.62%), respectively (p < 0.0001). The five-year survival rate ranged from 92.86% to 75.00%, for Luminal A, HER2 and TN subtypes, respectively (HR: 0.260 to 1.015; 95% CI: 0.043 to 3.594; p = 0.2589). Patients with HER2 positive (HER2+) breast tumors did not receive immunotherapy and chemotherapy application varied from 54.84% to 86.49% for Luminal A and HER2 subtypes, respectively (p = 0.0131).

CONCLUSIONS

The results of this study revealed a high percentage of HER2+ breast tumors and an increased rate of patients with TN tumors aged over 50 years. This emphasizes the need for establishing immunotherapy as an additional therapeutic option to improve clinical outcomes for patients with HER2+ tumors and to investigate the risk factors of TN breast cancer.

Receptor-defined subtypes of breast cancer in indigenous populations in Africa: a systematic review and meta-analysis

BACKGROUND

Breast cancer is the most common female cancer in Africa. Receptor-defined subtypes are a major determinant of treatment options and disease outcomes but there is considerable uncertainty regarding the frequency of poor prognosis estrogen receptor (ER) negative subtypes in Africa. We systematically reviewed publications reporting on the frequency of breast cancer receptor-defined subtypes in indigenous populations in Africa.

METHODS AND FINDINGS

Medline, Embase, and Global Health were searched for studies published between 1st January 1980 and 15th April 2014. Reported proportions of ER positive (ER+), progesterone receptor positive (PR+), and human epidermal growth factor receptor-2 positive (HER2+) disease were extracted and 95% CI calculated. Random effects meta-analyses were used to pool estimates. Fifty-four studies from North Africa (n=12,284 women with breast cancer) and 26 from sub-Saharan Africa (n=4,737) were eligible. There was marked between-study heterogeneity in the ER+ estimates in both regions (I2>90%), with the majority reporting proportions between 0.40 and 0.80 in North Africa and between 0.20 and 0.70 in sub-Saharan Africa. Similarly, large between-study heterogeneity was observed for PR+ and HER2+ estimates (I2>80%, in all instances). Meta-regression analyses showed that the proportion of ER+ disease was 10% (4%-17%) lower for studies based on archived tumor blocks rather than prospectively collected specimens, and 9% (2%-17%) lower for those with ≥ 40% versus those with <40% grade 3 tumors. For prospectively collected samples, the pooled proportions for ER+ and triple negative tumors were 0.59 (0.56-0.62) and 0.21 (0.17-0.25), respectively, regardless of region. Limitations of the study include the lack of standardized procedures across the various studies; the low methodological quality of many studies in terms of the representativeness of their case series and the quality of the procedures for collection, fixation, and receptor testing; and the possibility that women with breast cancer may have contributed to more than one study.

CONCLUSIONS

The published data from the more appropriate prospectively measured specimens are consistent with the majority of breast cancers in Africa being ER+. As no single subtype dominates in the continent availability of receptor testing should be a priority, especially for young women with early stage disease where appropriate receptor-specific treatment modalities offer the greatest potential for reducing years of life lost. Please see later in the article for the Editors' Summary.

Breast cancer in Sub-Saharan Africa: opportunities for prevention

Although breast cancer is a growing health problem in sub-Saharan Africa, reasons for its increased occurrence remain unclear. We reviewed the published literature to determine the magnitude of the increase in breast cancer, associated risk factors (including for breast cancer subtypes), and ways to reduce incidence and mortality. Some of the increased breast cancer occurrence likely reflects that women are living longer and adopting lifestyles that favor higher incidence rates. However, a greater proportion of breast cancers occur among premenopausal women as compared to elsewhere, which may reflect unique risk factors. Breast cancers diagnosed among African women reportedly include a disproportionate number of poor prognosis tumors, including hormone receptor negative, triple negative, and core basal phenotype tumors. However, it is unclear how lack of standardized methods for tissue collection, fixation, and classification contribute to these rates. Given appropriate classifications, it will be of interest to compare rates with other populations and to identify risk factors that relate to specific tumor subtypes. This includes not only risk factors that have been recognized in other populations but also some that may play unique roles among African women, such as genetic factors, microbiomata, xenoestrogens, hair relaxers, and skin lighteners. With limited opportunities for effective treatment, a focus is needed on identifying etiologic factors that may be amenable to intervention. It will also be essential to understand reasons why women delay seeking care after the onset of symptoms and for there to be educational campaigns about the importance of early detection.

Breast cancer survival in Ethiopia: a cohort study of 1,070 women

There is little information on breast cancer (BC) survival in Ethiopia and other parts of sub-Saharan Africa. Our study estimated cumulative probabilities of distant metastasis-free survival (MFS) in patients at Addis Ababa (AA) University Radiotherapy Center, the only public oncologic institution in Ethiopia. We analyzed 1,070 females with BC stage 1-3 seen in 2005-2010. Patients underwent regular follow-up; estrogen receptor-positive and -unknown patients received free endocrine treatment (an independent project funded by AstraZeneca Ltd. and facilitated by the Axios Foundation). The primary endpoint was distant metastasis. Sensitivity analysis (worst-case scenario) assumed that patients with incomplete follow-up had events 3 months after the last appointment. The median age was 43.0 (20-88) years. The median tumor size was 4.96 cm [standard deviation (SD) 2.81 cm; n = 709 information available]. Stages 1, 2 and 3 represented 4, 25 and 71%, respectively (n = 644). Ductal carcinoma predominated (79.2%, n = 1,070) as well as grade 2 tumors (57%, n = 509). Median follow-up was 23.1 (0-65.6) months, during which 285 women developed metastases. MFS after 2 years was 74% (69-79%), declining to 59% (53-64%) in the worst-case scenario. Patients with early stage (1-2) showed better MFS than patients with stage 3 (85 and 66%, respectively). The 5-year MFS was 72% for stages 1 and 2 and 33% for stage 3. We present a first overview on MFS in a large cohort of female BC patients (1,070 patients) from sub-Saharan Africa. Young age and advanced stage were associated with poor outcome.

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

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