Homozygous Sickle Cell Disease after Age of 40: Follow-Up of a Cohort of 209 Patients in Senegal, West Africa.

Objectives: The aim of this study was to describe the morbidity and mortality of homozygous sickle cell disease after the age of 40. Methods: This was a cohort study of 209 patients followed from 1994 to 2022. All hemoglobin electrophoresis-confirmed SS sickle cell patients over 40 years were included. A descriptive study of epidemiological, diagnostic, therapeutic, and evolutionary data was used to assess morbidity and mortality. Results: Sex ratio (M/F) was 0.6. Median age was 47 (41-75). According to morbidity, 95.1% had less than 3 vaso-occlusive crises/year. Acute anemia was the most frequent complication (52.63%). Chronic complications were noted in 32.5%. At diagnosis, mean hemoglobin was 8.1 g/dl ± 1.9, HbS was 86.5 ± 10, and HbF was 9.4 ± 7.6. Number of patients transfused was 66%. We noted that 8.1% of patients died, 29.2% were lost to follow-up, and 62.7% were still being followed up. The risk factors identified for death were geographical origin, comorbidity, high HbS, low HbF, and thrombocytosis. Conclusion: This study shows that homozygous SCD is increasingly becoming an adult disease and that it can be carried into old age in Africa. Advanced age over 40 is marked by an upsurge in chronic complications, making it essential to set up a screening program and to organize multidisciplinary follow-up.

Uncovering the genetic architecture and evolutionary roots of androgenetic alopecia in African men.

Androgenetic alopecia is a highly heritable trait. However, much of our understanding about the genetics of male pattern baldness comes from individuals of European descent. Here, we examined a novel dataset comprising 2,136 men from Ghana, Nigeria, Senegal, and South Africa that were genotyped using a custom array. We first tested how genetic predictions of baldness generalize from Europe to Africa, finding that polygenic scores from European GWAS yielded AUC statistics that ranged from 0.513 to 0.546, indicating that genetic predictions of baldness in African populations performed notably worse than in European populations. Subsequently, we conducted the first African GWAS of androgenetic alopecia, focusing on self-reported baldness patterns at age 45. After correcting for present age, population structure, and study site, we identified 266 moderately significant associations, 51 of which were independent (p-value < 10-5, r2 < 0.2). Most baldness associations were autosomal, and the X chromosomes does not appear to have a large impact on baldness in African men. Finally, we examined the evolutionary causes of continental differences in genetic architecture. Although Neanderthal alleles have previously been associated with skin and hair phenotypes, we did not find evidence that European-ascertained baldness hits were enriched for signatures of ancient introgression. Most loci that are associated with androgenetic alopecia are evolving neutrally. However, multiple baldness-associated SNPs near the EDA2R and AR genes have large allele frequency differences between continents. Collectively, our findings illustrate how evolutionary history contributes to the limited portability of genetic predictions across ancestries.

Association of haemolysis markers, blood viscosity and microcirculation function with organ damage in sickle cell disease in sub-Saharan Africa (the BIOCADRE study).

Sickle cell anaemia (SCA) is a monogenic disease with a highly variable clinical course. We aimed to investigate associations between microvascular function, haemolysis markers, blood viscosity and various types of SCA-related organ damage in a multicentric sub-Saharan African cohort of patients with SCA. In a cross-sectional study, we selected seven groups of adult patients with SS phenotype in Dakar and Bamako based on the following complications: leg ulcer, priapism, osteonecrosis, retinopathy, high tricuspid regurgitant jet velocity (TRV), macro-albuminuria or none. Clinical assessment, echocardiography, peripheral arterial tonometry, laboratory tests and blood viscosity measurement were performed. We explored statistical associations between the biological parameters and the six studied complications. Among 235 patients, 58 had high TRV, 46 osteonecrosis, 43 priapism, 33 leg ulcers, 31 retinopathy and 22 macroalbuminuria, whereas 36 had none of these complications. Multiple correspondence analysis revealed no cluster of complications. Lactate dehydrogenase levels were associated with high TRV, and blood viscosity was associated with retinopathy and the absence of macroalbuminuria. Despite extensive phenotyping of patients, no specific pattern of SCA-related complications was identified. New biomarkers are needed to predict SCA clinical expression to adapt patient management, especially in Africa, where healthcare resources are scarce.

Learning from intersectoral initiatives to respond to the needs of refugees, asylum seekers, and migrants without status in the context of COVID-19 in Quebec and Ontario: a qualitative multiple case study protocol.

BACKGROUND: Refugees, asylum seekers, and migrants without status experience precarious living and working conditions that disproportionately expose them to coronavirus disease 2019 (COVID-19). In the two most populous Canadian provinces (Quebec and Ontario), to reduce the vulnerability factors experienced by the most marginalized migrants, the public and community sectors engage in joint coordination efforts called intersectoral collaboration. This collaboration ensures holistic care provisioning, inclusive of psychosocial support, assistance to address food security, and educational and employment assistance. This research project explores how community and public sectors collaborated on intersectoral initiatives during the COVID-19 pandemic to support refugees, asylum seekers, and migrants without status in the cities of Montreal, Sherbrooke, and Toronto, and generates lessons for a sustainable response to the heterogeneous needs of these migrants. METHODS: This theory-informed participatory research is co-created with socioculturally diverse research partners (refugees, asylum seekers and migrants without status, employees of community organizations, and employees of public organizations). We will utilize Mirzoev and Kane's framework on health systems' responsiveness to guide the four phases of a qualitative multiple case study (a case being an intersectoral initiative). These phases will include (1) building an inventory of intersectoral initiatives developed during the pandemic, (2) organizing a deliberative workshop with representatives of the study population, community, and public sector respondents to select and validate the intersectoral initiatives, (3) interviews (n = 80) with community and public sector frontline workers and managers, municipal/regional/provincial policymakers, and employees of philanthropic foundations, and (4) focus groups (n = 80) with refugees, asylum seekers, and migrants without status. Qualitative data will be analyzed using thematic analysis. The findings will be used to develop discussion forums to spur cross-learning among service providers. DISCUSSION: This research will highlight the experiences of community and public organizations in their ability to offer responsive services for refugees, asylum seekers, and migrants without status in the context of a pandemic. We will draw lessons learnt from the promising practices developed in the context of COVID-19, to improve services beyond times of crisis. Lastly, we will reflect upon our participatory approach-particularly in relation to the engagement of refugees and asylum seekers in the governance of our research.

[Nephropathy associated with monoclonal immunoglobulins: From clonal expansion B to renal toxicity of pathological immunoglobulins]. / Les néphropathies associées aux immunoglobulines monoclonales : de l'expansion clonale B à la toxicité rénale des immunoglobulines pathologiques.

Germinal center regulation pathways are often involved in lymphomagenesis and myelomagenesis. Most of the lymphomas (and multiple myeloma) derive from post-germinal center B-cells that have undergone somatic hypermutation and class switch recombination. Hence, B-cell clonal expansion can be responsible for the presence of a monoclonal component (immunoglobulin) of variable titer which, owing to physicochemical properties, can provoke pathologically defined entities of diseases. These diseases can affect any functional part of the kidney, by multiple mechanisms, either well known or not. The presence of renal deposition is influenced by germinal gene involved, immunoglobulin primary structure, post-translational modifications and microenvironmental interactions. The two ways immunoglobulin can cause kidney toxicity are (i) an excess of production (overcoming catabolism power by proximal tubule epithelial cells) with an excess of free light chains within the distal tubules and a subsequent risk of precipitation due to local physicochemical properties; (ii) by structural characteristics that predispose immunoglobulin to a renal disease (whatever their titer). The purpose of this manuscript is to review literature concerning the pathophysiology of renal toxicities of clonal immunoglobulin, from molecular B-cell expansion mechanisms to immunoglobulin renal toxicity.

Testing the generalizability of ancestry-specific polygenic risk scores to predict prostate cancer in sub-Saharan Africa.

BACKGROUND: Genome-wide association studies do not always replicate well across populations, limiting the generalizability of polygenic risk scores (PRS). Despite higher incidence and mortality rates of prostate cancer in men of African descent, much of what is known about cancer genetics comes from populations of European descent. To understand how well genetic predictions perform in different populations, we evaluated test characteristics of PRS from three previous studies using data from the UK Biobank and a novel dataset of 1298 prostate cancer cases and 1333 controls from Ghana, Nigeria, Senegal, and South Africa. RESULTS: Allele frequency differences cause predicted risks of prostate cancer to vary across populations. However, natural selection is not the primary driver of these differences. Comparing continental datasets, we find that polygenic predictions of case vs. control status are more effective for European individuals (AUC 0.608-0.707, OR 2.37-5.71) than for African individuals (AUC 0.502-0.585, OR 0.95-2.01). Furthermore, PRS that leverage information from African Americans yield modest AUC and odds ratio improvements for sub-Saharan African individuals. These improvements were larger for West Africans than for South Africans. Finally, we find that existing PRS are largely unable to predict whether African individuals develop aggressive forms of prostate cancer, as specified by higher tumor stages or Gleason scores. CONCLUSIONS: Genetic predictions of prostate cancer perform poorly if the study sample does not match the ancestry of the original GWAS. PRS built from European GWAS may be inadequate for application in non-European populations and perpetuate existing health disparities.

Validation of a multi-ancestry polygenic risk score and age-specific risks of prostate cancer: A meta-analysis within diverse populations.

Background: We recently developed a multi-ancestry polygenic risk score (PRS) that effectively stratifies prostate cancer risk across populations. In this study, we validated the performance of the PRS in the multi-ancestry Million Veteran Program and additional independent studies. Methods: Within each ancestry population, the association of PRS with prostate cancer risk was evaluated separately in each case-control study and then combined in a fixed-effects inverse-variance-weighted meta-analysis. We further assessed the effect modification by age and estimated the age-specific absolute risk of prostate cancer for each ancestry population. Results: The PRS was evaluated in 31,925 cases and 490,507 controls, including men from European (22,049 cases, 414,249 controls), African (8794 cases, 55,657 controls), and Hispanic (1082 cases, 20,601 controls) populations. Comparing men in the top decile (90-100% of the PRS) to the average 40-60% PRS category, the prostate cancer odds ratio (OR) was 3.8-fold in European ancestry men (95% CI = 3.62-3.96), 2.8-fold in African ancestry men (95% CI = 2.59-3.03), and 3.2-fold in Hispanic men (95% CI = 2.64-3.92). The PRS did not discriminate risk of aggressive versus nonaggressive prostate cancer. However, the OR diminished with advancing age (European ancestry men in the top decile: ≤55 years, OR = 7.11; 55-60 years, OR = 4.26; >70 years, OR = 2.79). Men in the top PRS decile reached 5% absolute prostate cancer risk ~10 years younger than men in the 40-60% PRS category. Conclusions: Our findings validate the multi-ancestry PRS as an effective prostate cancer risk stratification tool across populations. A clinical study of PRS is warranted to determine whether the PRS could be used for risk-stratified screening and early detection. Funding: This work was supported by the National Cancer Institute at the National Institutes of Health (grant numbers U19 CA214253 to C.A.H., U01 CA257328 to C.A.H., U19 CA148537 to C.A.H., R01 CA165862 to C.A.H., K99 CA246063 to B.F.D, and T32CA229110 to F.C), the Prostate Cancer Foundation (grants 21YOUN11 to B.F.D. and 20CHAS03 to C.A.H.), the Achievement Rewards for College Scientists Foundation Los Angeles Founder Chapter to B.F.D, and the Million Veteran Program-MVP017. This research has been conducted using the UK Biobank Resource under application number 42195. This research is based on data from the Million Veteran Program, Office of Research and Development, and the Veterans Health Administration. This publication does not represent the views of the Department of Veteran Affairs or the United States Government.

Cancer in sub-Saharan Africa: a Lancet Oncology Commission.

In sub-Saharan Africa (SSA), urgent action is needed to curb a growing crisis in cancer incidence and mortality. Without rapid interventions, data estimates show a major increase in cancer mortality from 520 348 in 2020 to about 1 million deaths per year by 2030. Here, we detail the state of cancer in SSA, recommend key actions on the basis of analysis, and highlight case studies and successful models that can be emulated, adapted, or improved across the region to reduce the growing cancer crises. Recommended actions begin with the need to develop or update national cancer control plans in each country. Plans must include childhood cancer plans, managing comorbidities such as HIV and malnutrition, a reliable and predictable supply of medication, and the provision of psychosocial, supportive, and palliative care. Plans should also engage traditional, complementary, and alternative medical practices employed by more than 80% of SSA populations and pathways to reduce missed diagnoses and late referrals. More substantial investment is needed in developing cancer registries and cancer diagnostics for core cancer tests. We show that investments in, and increased adoption of, some approaches used during the COVID-19 pandemic, such as hypofractionated radiotherapy and telehealth, can substantially increase access to cancer care in Africa, accelerate cancer prevention and control efforts, increase survival, and save billions of US dollars over the next decade. The involvement of African First Ladies in cancer prevention efforts represents one practical approach that should be amplified across SSA. Moreover, investments in workforce training are crucial to prevent millions of avoidable deaths by 2030. We present a framework that can be used to strategically plan cancer research enhancement in SSA, with investments in research that can produce a return on investment and help drive policy and effective collaborations. Expansion of universal health coverage to incorporate cancer into essential benefits packages is also vital. Implementation of the recommended actions in this Commission will be crucial for reducing the growing cancer crises in SSA and achieving political commitments to the UN Sustainable Development Goals to reduce premature mortality from non-communicable diseases by a third by 2030.

Urethral Prolapse Case Report: Surgical and Social Considerations in Senegal.

We present three cases of urethral prolapse in prepubertal females in Senegal who presented with vulvar bleeding. Careful gynecologic and urologic physical exams were performed and revealed urethral origin and prolapse. Conservative versus surgical approaches were taken in different patients, but ultimately, each patient received a urethral meatoplasty. Surgical excision of these masses yielded a full recovery in the patients. A careful review of the literature was then undertaken and showed that surgical excision or ligation of the prolapse is preferable to more conservative treatment. The case series article discusses the rare occurrence of urethral prolapse, as well as the epidemiology and prognostic and therapeutic implications of urethral prolapse in prepubertal females. Introduction. Urethral prolapse is a rare condition occurring mostly in young black females. It can be worrying to the parents as it often causes vulvar bleeding. Case Presentation. We present three cases of urethral prolapse in prepubertal females who presented with vulvar bleeding. Physical exams were performed and revealed urethral origin and prolapse. Each patient underwent a urethral meatoplasty and subsequently experienced a full recovery after respective follow-up of 2 years, 1 year, and 1 year. Conclusion. Urethral prolapse is a rare condition which can be managed successfully by surgery. Plain Language Summary. This case report on pediatric urethral prolapse showcases the different presentations and modalities of treatment, as the literature does not show that a specific treatment is always undertaken. In some countries, there are strong social considerations and they demonstrate difficulty separating sexual abuse from genitourinary pathologies, which are important to address in the treatment of these conditions.

Transfusion Practice, Post-Transfusion Complications and Risk Factors in Sickle Cell Disease in Senegal, West Africa.

CONTEXT AND OBJECTIVES: Blood transfusions (BT) remain a mainstay of therapy for patients with sickle cell disease (SCD) but pose significant clinical challenges. We aim to assess infectious markers, red cell alloimmunization, and iron overload secondary to BT in SCD patients. MATERIALS AND METHODS: This case-control study included 253 SCD (153 SCD-transfused and 100 SCD non-transfused). We evaluated the transfusion practice (modalities, indications), post-transfusion complications (infections, alloimmunization, iron overload), and risk factors of these complications (socio-demographic, clinical, biological). RESULTS: Median age was 28.5 years (5 - 59). The sex ratio was 0.86. Homozygous SCD was the most common (95.3%). Simple BT was performed in 92.8% and transfusion exchange in 18.9%. Transfusion indications were dominated by acute anemia (57.06%) and vaso-occlusive crisis (VOCs) (14%). Red blood cell concentrates (RBCSs) were administered to 93.46%. The median RBCs received per patient was 10 (2 - 48). The prevalence of VHC in SCD-transfused was 1.33% and 2% for VHB. Anti-HIV antibodies were not found. Red cell alloimmunization frequency was 16%. The most common alloantibodies were anti-rhesus (34.19%) and anti-Kell (23.67%). Iron overload was detected in 7.84%. The number of RBCs transfused was the only risk factor for alloimmunization (p = 0.03) and iron overload (p = 0.023). BT frequency was not related to infectious transmission. CONCLUSION: BT therapy is still a risk for SCD polytransfused patients despite advances in blood safety. Although infectious transmission has rare, the risk of alloimmunization and iron overload is high in these patients.

A case of pyelo-ureteral junction bilharzioma.

Bilharziomas are inflammatory tumour-like masses which often pose the problem of differential diagnosis with neoplastic processes. Its location at the pyelo-ureteral junction is very uncommon. The pre-operative diagnosis of bilharzia of the pyelo-ureteral junction is difficult. Indeed, the diagnosis is most often made on anatomo-pathological examination of the surgical specimen, which rarely allows for conservative treatment. We report one case of pyeloureteral junction bilharzioma in children living in bilharzia endemic areas and discuss the diagnostic and therapeutic issues of these cases.

Prostate tumors of native men from West Africa show biologically distinct pathways-A comparative genomic study.

BACKGROUND: Native African men (NAM) experience a disproportionate burden of prostate cancer (PCa) and have higher mortality rates compared to European American men (EAM). While socioeconomic status has been implicated as a driver of this disparity, little is known about the genomic mechanisms and distinct biological pathways that are associated with PCa of native men of African origin. METHODS: To understand biological factors that contribute to this disparity we utilized a total of 406 multi-institutional localized PCa samples, collected by Men of African Descent and Carcinoma of the Prostate biospecimen network and Moffitt Cancer Center/University of Pennsylvania Health science system. We performed comparative genomics and immunohistochemistry to identify the biomarkers that are highly enriched in NAM from west Africa and compared them with African American Men (AAM) and EAM. Quantified messenger RNA expression and Median H scores based on immune reactivity of staining cells, were compared using Mann Whitney test. For gene expression analysis, p values were further adjusted for multiple comparisons using false discovery rates. RESULTS: Immunohistochemical analysis on selected biomarkers showed a consistent association between ETS related gene (ERG) status and race with 83% of NAM exhibiting tumors that lacked TMPRSS2-ERG translocation (ERGnegative ) as compared to AAM (71%) and EAM (52%). A higher proportion of NAM (29%) were also found to be double negative (ERGnegative and PTENLoss ) as compared to AAM (6%) and EAM (7%). NAM tumors had significantly higher immunoreactivity (H-score) for PSMA, and EZH2, whereas they have lower H-score for PTEN, MYC, AR, RB and Racemase, (all p < .05). Comparative genomics revealed that NAM had significant transcriptomic variability in AR-activity score. In pathways enrichment analysis NAM tumors exhibited the enrichment of proinflammatory pathways including cytokine, interleukins, inflammatory response, and nuclear factor kappa B signaling. CONCLUSIONS: Prostate tumors in NAM are genomically distinct and are characterized by the dysregulation of several biomarkers. Furthermore, these tumors are also highly enriched for the major proinflammatory pathways. These distinct biological features may have implications for diagnosis and response to targeted therapy among Black men, globally.

New Insights Into c.815_824dup Pathogenic Variant of BRCA1 in Inherited Breast Cancer: A Founder Mutation of West African Origin.

Founder mutations have been reported in BRCA1 and BCRA2 in different ethnic groups with inherited breast cancer. Testing of targeted mutations in specific populations is important for cancer prevention in mutation carriers. In Sub-Saharan Africa, only a few studies have reported specific founder mutations in inherited breast cancer. The pathogenic variant c.815_824dup of BRCA1 has been reported as the most frequent among African American populations with inherited breast cancer and was supposed to have a West African origin. Recent report from Senegal identified this variant in women with inherited breast cancer at the highest frequency ever reported. The variant was linked to a common haplotype confirming its founder effect in West Africa. In this article, we review the mutation history of c.815_824dup and discuss how it spread out of Africa through the transatlantic slave trade.

Epidemiological and Diagnostic Aspects of Bladder Bilharziomas in the Urology Department of Idrissa Pouye General Hospital (HOGIP).

Objective: The aim of our study is to assess the diagnostic aspects of bladder bilharzioma in the Urology Department of Idrissa Pouye General Hospital (Senegal). Materials and Methods: It is a descriptive study from January 2013 to December 2018. The patients included in the study were those who had anatomopathological examination of bladder biopsy that showed a schistosomiasis pseudotumor of the bladder. The variables studied were sociodemographic, clinical symptoms, imaging findings, histology, and treatment. The data have been saved and analyzed by the 2013 Excel software. Results: Thirteen patients were included in our study. The average age was 27 ± 12.1 years. Sex ratio was 1.6. The majority of the patients were from the northern part of Senegal. Hematuria was the main symptom for all the patients. Cystoscopy was performed for all the patients and showed 5 granulomas and 8 fibrocalcic polyps. A transurethral resection of the bladder was performed, and treatment with praziquantel (40 mg/kg of bodyweight) has been carried out. One patient presented precancerous lesions such as metaplasia and dysplasia of the bladder mucosa. After a median follow-up of 40 months (6-57 months), ten patients had a favorable clinical and endoscopic outcome. Conclusion: Granulomas and fibrocalcic polyps of the bladder mucosa are, respectively, confused with squamous cell carcinoma and bladder lithiasis in endemic areas of schistosomiasis. Good cystoscopy interpretation can provide the diagnosis of bladder bilharzioma and start the treatment.

Unusual Presentation of Priapism Associated with Acute and Chronic Myeloid Leukemia in Two Patients: Emergency Management.

Priapism is a rare urological emergency. It is rarely a telltale sign of myeloid leukemia. We report two cases of acute myeloid leukemia in a child and chronic myeloid leukemia in a young adult presenting with priapism. Puncture irrigation of the corpora cavernosa followed by systemic treatment to lower the hyperviscosity of the blood due to leukemia provided optimal outcome. Prompt emergency management is required to lower the complication of erectile dysfunction.

Surgical Management of Urolithiasis of the Upper Tract - Current Trend of Endourology in Africa.

Urolithiasis is a global pathology with increasing prevalence rate. The lifetime recurrence of urolithiasis ranges from 10-75% creating a public health crisis in affected regions. The epidemiology of urolithiasis in most parts of Africa and Asia remains poorly documented as incidence and prevalence rates in these settings are extrapolated from hospital admissions. The surgical management of kidney and ureteral stones is based on the stone location, size, the patient's preference and the institutional capacity. To date, the available modalities in the management of urolithiasis includes external shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), ureterorenoscopy (URS) including flexible and semirigid ureteroscopy. However, regarding the lack of endourological equipment and expertise in most parts of Sub-Saharan Africa (SSA), most urological centers in these regions still consider open surgery for kidney and ureteral stones. This review explores the current trend and surgical management of upper tract urolithiasis in SSA with insight on the available clinical guidelines.

Is Schistosomiasis a Risk Factor for Bladder Cancer? Evidence-Based Facts.

Background . Globally, approximately 20% of malignancy are caused by infection. Schistosoma infection is a major cause of bladder in most part of Africa. In 2018 alone, there were approximately 549,393 new cases and 199,922 deaths from bladder cancer. The presence of Schistosoma ova in the venous plexus of the bladder induces a cascade of inflammation causing significant tissue damage and granulomatous changes. Methodology. A literature review was conducted from 1995 to 2019 using PubMed, Google Scholar, African Journal Online, and Google databases. Relevant data on the association of "Schistosomiasis and Bladder cancer" in sub-Saharan Africa (SSA) were retrieved. Evidence Synthesis. Results from research using animal models to establish the carcinogenesis of Schistosoma and bladder cancer have been helpful but inconclusive. Immunoregulatory cytokines and genetic marker have been identified to play a role in the pathogenesis. In some parts of sub-Saharan Africa, there has been close association of squamous cell carcinoma and histological evidence of Schistosoma ova. Conclusion. There are some data to support the association between schistosomiasis and bladder cancer in sub-Saharan Africa. However, these have been limited by their design and may not sufficiently establish carcinogenesis. There is a need for more genomic and molecular research to better characterize S. haematobium and its effects on the bladder. Such goal will contribute immensely to Schistosoma bladder cancer prevention and control.

A Custom Genotyping Array Reveals Population-Level Heterogeneity for the Genetic Risks of Prostate Cancer and Other Cancers in Africa.

Although prostate cancer is the leading cause of cancer mortality for African men, the vast majority of known disease associations have been detected in European study cohorts. Furthermore, most genome-wide association studies have used genotyping arrays that are hindered by SNP ascertainment bias. To overcome these disparities in genomic medicine, the Men of African Descent and Carcinoma of the Prostate (MADCaP) Network has developed a genotyping array that is optimized for African populations. The MADCaP Array contains more than 1.5 million markers and an imputation backbone that successfully tags over 94% of common genetic variants in African populations. This array also has a high density of markers in genomic regions associated with cancer susceptibility, including 8q24. We assessed the effectiveness of the MADCaP Array by genotyping 399 prostate cancer cases and 403 controls from seven urban study sites in sub-Saharan Africa. Samples from Ghana and Nigeria clustered together, whereas samples from Senegal and South Africa yielded distinct ancestry clusters. Using the MADCaP array, we identified cancer-associated loci that have large allele frequency differences across African populations. Polygenic risk scores for prostate cancer were higher in Nigeria than in Senegal. In summary, individual and population-level differences in prostate cancer risk were revealed using a novel genotyping array. SIGNIFICANCE: This study presents an Africa-specific genotyping array, which enables investigators to identify novel disease associations and to fine-map genetic loci that are associated with prostate and other cancers.