Figure S1: Consort diagram of the analyzed samples

Figure S5: MHC I expression in SSA

Figure S6: Multivariate Cox regression analysis of patient's survival.

Figure S3: Immune cell subpopulations in SSA

Figure S4:PD-L1 expression and cytotoxicity

BACKGROUND AND OBJECTIVE:The impact of germline pathogenic variants (PVs) in cancer predisposition genes on risk of prostate cancer (PCa) remains understudied in large populations of African ancestry. This study aims to characterize the range of genetic risk of PCa and aggressive disease phenotypes in men of African ancestry. METHODS:We analyzed 7176 PCa cases and 4873 controls from seven countries across North America and Africa to assess the association between PVs in 37 cancer predisposition genes and the risk of overall, aggressive, and metastatic PCa. Genes significantly associated with PCa risk were used to estimate lifetime absolute risk based on family history, polygenic risk score (PRS), and PV carrier status. KEY FINDINGS AND LIMITATIONS:PVs in ATM, BRCA2, CHEK2, HOXB13, and PALB2 were presented in 4% of aggressive/metastatic PCa cases and were significantly associated with an increased risk of aggressive PCa (odds ratio 2.18-5.96, p < 0.05). Lifetime absolute risk varied widely depending on PV carrier status, PRS, and family history, ranging from 3.0% to 74% for overall PCa, 0.6% to 41% for aggressive PCa, and 0.2% to 37% for metastatic PCa. PV carriers with a positive family history and a PRS in the 90th percentile had seven, 18, and 34 times the risks of overall, aggressive, and metastatic PCa, respectively, compared with average-risk individuals. Oversampling of aggressive cases may limit the generalizability of these findings to screening populations. CONCLUSIONS AND CLINICAL IMPLICATIONS:Integration of PV status, PRS, and family history enables more refined PCa risk estimates. The wide range of PCa risk observed among men of African ancestry in our study supports future prospective studies in the development of risk-stratified cancer screening programs to identify high-risk individuals who may benefit from screening at an earlier age.

Men of African descent have the highest prostate cancer incidence and mortality rates, yet the genetic basis of prostate cancer in African men has been understudied. We used genomic data from 3,963 cases and 3,509 controls from Ghana, Nigeria, Senegal, South Africa and Uganda to infer ancestry-specific genetic architectures and fine-map disease associations. Fifteen independent associations at 8q24.21, 6q22.1 and 11q13.3 reached genome-wide significance, including four new associations. Intriguingly, multiple lead associations are private alleles, a pattern arising from recent mutations and the out-of-Africa bottleneck. These African-specific alleles contribute to haplotypes with odds ratios above 2.4. We found that the genetic architecture of prostate cancer differs across Africa, with effect size differences contributing more to this heterogeneity than allele frequency differences. Population genetic analyses reveal that African prostate cancer associations are largely governed by neutral evolution. Collectively, our findings emphasize the utility of conducting genetic studies that use diverse populations. Genome-wide association analyses of prostate cancer in men from sub-Saharan Africa identify population-specific risk variants and regional differences in effect sizes. Founder effects contribute to continental differences in the genetic architecture of prostate cancer.

In sub-Saharan Africa, colorectal cancer (CRC) has historically been considered a rare disease, although some previous studies have suggested that the incidence is increasing. We examine time trends in the incidence of CRC using data from 12 population-based cancer registries in 11 countries of sub-Saharan Africa that were able to provide time series data for periods of 12 or more years, or with earlier data with which recent rates may be compared. Age-standardized incidence rates were highest in the higher-income countries, and were increasing in all of the populations studied, and these increases were statistically significant in all but three. Current evidence has suggested a link between the increased adoption of western lifestyle habits with colorectal cancer, and along with increasing urbanization of African populations, there is an increase in body weight, as well as evidence of increasing consumption of meat, sugars, and alcohol.

PURPOSEProstate cancer disproportionately affects men of African descent, yet their representation in tissue-based studies is limited. This multinational, multicenter pilot study aims to establish the groundwork for collaborative research on prostate cancer in sub-Saharan Africa.METHODSThe Men of African Descent and Carcinoma of the Prostate network formed a pathologist working group representing eight institutions in five African countries. Formalin-fixed paraffin-embedded prostate tissue specimens were collected from Senegal, Nigeria, and Ghana. Histology slides were produced and digitally scanned. A central genitourinary pathologist (P.L.) and eight African general pathologists reviewed anonymized digital whole-slide images for International Society of Urological Pathology grade groups and other pathologic parameters. Discrepancies were re-evaluated, and consensus grading was assigned. A virtual training seminar on prostate cancer grading was followed by a second assessment on a subcohort of the same tissue set.RESULTSOf 134 tissue blocks, 133 had evaluable tissue; 13 lacked cancer evidence, and four were of insufficient quality. Post-training, interobserver agreement for grade groups improved to 56%, with a median Cohen's quadratic weighted kappa of 0.83 (mean, 0.74), compared with an initial 46% agreement and a quadratic weighted kappa of 0.77. Interobserver agreement between African pathologist groups was 40%, with a quadratic weighted kappa of 0.66 (95% CI, 0.51 to 0.76). African pathologists tended to overgrade (36%) more frequently than undergrade (18%) compared with the reference genitourinary pathologist. Interobserver variability tended to worsen with a decrease in tissue quality.CONCLUSIONTissue-based studies on prostate cancer in men of African descent are essential for a better understanding of this common disease. Standardized tissue handling protocols are crucial to ensure good tissue quality and data. The use of digital slide imaging can enhance collaboration among pathologists in multinational, multicenter studies.

Abstract Background: Gastrointestinal tract (GIT) tumors are predominantly seen among middle-aged and elderly persons. However, there are reports of an increasing incidence among adolescents and young adults. Objective: We sought to describe the morphological characteristics of malignancies involving the GIT among adolescents and young adults in our center. Materials and Methods: This is a retrospective review of all histologically diagnosed cases of gastrointestinal malignancies in persons between the ages of 10 and 35, over a 10-year period (2010–2019). Results: There were 79 cases of GIT tumors in adolescents and young adults during the study period amounting to 14.2% of total GIT malignancies. The male: female ratio was 1:1.1. Colonic malignancies predominated, accounting for 75% of cases; these were mostly adenocarcinomas. Gastric cancers showed a female predilection; small intestinal tumors were observed more in males. Conclusion: Gastrointestinal tract tumors affecting adolescents and young adults are not uncommon. Most of these tumors are adenocarcinomas and affect the colon. Gastric cancers showed a female predilection.

BACKGROUND AND OBJECTIVE:The demonstration of HER2 in gastric adenocarcinoma (GA) tissues by immunohistochemistry assists in deciding whether targeted therapy would optimise the treatment of GA patients who are HER2 positive. However, this has not been extensively studied in our patients hence the need for this study.METHODS:Recipient tissue microarray blocks were constructed from donor archival formalin fixed paraffin embedded gastric tumour tissue from 80 patients seen over a period of 17 years in a retrospective descriptive study. Slides cut from these blocks were stained with antihuman HER2 antibody by immunohistochemistry and scored using the trastuzumab in gastric adenocarcinomas (ToGA) trial criteria. Data on age, gender, site of lesion and histological subtype of the gastric adenocarcinomas were also retrieved and reviewed.RESULTS:Eighty cases (52 males and 28 females; male to female ratio of 1.9:1), 55.65 ±13.50 years (modal age group 60-69 years), were studied. Most tumours (91.2%) involved the distal parts (pylorus, antrum and body) with a few (8.8%) involving the proximal part (cardia and fundus) of the stomach. HER2 was overexpressed in a total of 6 (7.5%) cases only. Two of seven (28.6%) proximal tumours showed HER2 positivity whereas only 4 of 73 (5.5%) of the distal tumours showed HER2 positivity.CONCLUSION:We had only a slightly lower HER2 overexpression rate than in studies from many other parts of the world. The observed overexpression was significantly higher in proximal than distally located tumours suggesting that distal tumours are less likely to respond to Trastuzumab than proximal tumours. The known association of distal gastric tumours with Helicobacter pylori infection probably provides for a possible difference in the molecular aetiopathogenesis of GAs by site of occurrence. The exact mechanisms for proximal gastric carcinogenesis remain to be more clearly elucidated. More studies, including clinical trials with larger sample sizes, are recommended to elucidate this differential expression of HER2 in gastric adenocarcinoma.

Background:Triple-negative breast cancers (TNBC) have been particularly challenging to manage due to their lack of intrinsic cellular receptors, with the resultant relatively higher morbidity and mortality. Recently, the programmed cell death 1/programmed cell death ligand 1 (PD-1/PD- L1) immune checkpoint pathway has become the focus of immunotherapy, especially for TNBCs. This study aimed to determine the pattern of expression of PD-L1 in TNBC cases in Benin City.Methods:It was a 3-year retrospective study that involved the PD-L1 immunostaining of the TNBC cases that were diagnosed in the Department of Anatomical Pathology, University of Benin Teaching Hospital, Benin City, from January 1, 2017 to December 31, 2019.Result:Ninety-two cases of TNBC were tested for PD-L1 expression. Thirteen (14.1%) of the TNBC cases were PDL1 positive to varying degrees on tumour and immune cells. Diffuse tumoural PD-L1 staining was seen in 4 (30.8%) of the PD-L1 positive cases. PD-L1 expression was significantly associated with increasing age up to the fifth decade (p =0.030). All the PD-L1 positive TNBC were invasive breast carcinoma of no special type and mostly grade 2 tumours; however, there was no significant association between PD-L1 expression and histological subtype or grade.Conclusion:PD-L1 expression was shown to occur at a relatively low rate among TNBC cases in this environment and was significantly associated with increasing age. This study has shown that 14.1% (1 in 7) of our TNBC patients could benefit from immune checkpoint inhibitor therapy.

The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry ( P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups.

Abstract The low overall survival rates of patients with breast cancer in sub-Saharan Africa (SSA) are driven by regionally differing tumor biology, advanced tumor stages at diagnosis, and limited access to therapy. However, it is not known whether regional differences in the composition of the tumor microenvironment (TME) exist and affect patients’ prognosis. In this international, multicentre cohort study, 1,237 formalin-fixed, paraffin-embedded breast cancer samples, including samples of the “African Breast Cancer-Disparities in Outcomes (ABC-DO) Study,” were analyzed. The immune cell phenotypes, their spatial distribution in the TME, and immune escape mechanisms of breast cancer samples from SSA and Germany (n = 117) were investigated using histomorphology, conventional and multiplex IHC, and RNA expression analysis. The data revealed no regional differences in the number of tumor-infiltrating lymphocytes (TIL) in the 1,237 SSA breast cancer samples, while the distribution of TILs in different breast cancer IHC subtypes showed regional diversity, particularly when compared with German samples. Higher TIL densities were associated with better survival in the SSA cohort (n = 400), but regional differences concerning the predictive value of TILs existed. High numbers of CD163+ macrophages and CD3+CD8+ T cells accompanied by reduced cytotoxicity, altered IL10 and IFNγ levels and downregulation of MHC class I components were predominantly detected in breast cancer samples from Western SSA. Features of nonimmunogenic breast cancer phenotypes were associated with reduced patient survival (n = 131). We therefore conclude that regional diversity in the distribution of breast cancer subtypes, TME composition, and immune escape mechanisms should be considered for therapy decisions in SSA and the design of personalized therapies. See related Spotlight by Bergin et al., p. 705

Men of African descent have the highest prostate cancer (CaP) incidence and mortality rates, yet the genetic basis of CaP in African men has been understudied. We used genomic data from 3,963 CaP cases and 3,509 controls recruited in Ghana, Nigeria, Senegal, South Africa, and Uganda, to infer ancestry-specific genetic architectures and fine-mapped disease associations. Fifteen independent associations at 8q24.21, 6q22.1, and 11q13.3 reached genome-wide significance, including four novel associations. Intriguingly, multiple lead SNPs are private alleles, a pattern arising from recent mutations and the out-of-Africa bottleneck. These African-specific alleles contribute to haplotypes with odds ratios above 2.4. We found that the genetic architecture of CaP differs across Africa, with effect size differences contributing more to this heterogeneity than allele frequency differences. Population genetic analyses reveal that African CaP associations are largely governed by neutral evolution. Collectively, our findings emphasize the utility of conducting genetic studies that use diverse populations.

Background: Genetic factors play an important role in prostate cancer (PCa) susceptibility.Objective: To discover common genetic variants contributing to the risk of PCa in men of African ancestry.Design, setting, and participants: We conducted a meta-analysis of ten genome-wide association studies consisting of 19 378 cases and 61 620 controls of African ancestry. Outcome measurements and statistical analysis: Common genotyped and imputed variants were tested for their association with PCa risk. Novel susceptibility loci were identified and incorporated into a multiancestry polygenic risk score (PRS). The PRS was evaluated for associations with PCa risk and disease aggressiveness.Results and limitations: Nine novel susceptibility loci for PCa were identified, of which seven were only found or substantially more common in men of African ancestry, including an African-specific stop-gain variant in the prostate-specific gene anoctamin 7 (ANO7). A multiancestry PRS of 278 risk variants conferred strong associations with PCa risk in African ancestry studies (odds ratios [ORs] >3 and >5 for men in the top PRS decile and percentile, respectively). More importantly, compared with men in the 40-60% PRS category, men in the top PRS decile had a significantly higher risk of aggressive PCa (OR = 1.23, 95% confidence interval = 1.10-1.38, p = 4.4 x 10-4). Conclusions: This study demonstrates the importance of large-scale genetic studies in men of African ancestry for a better understanding of PCa susceptibility in this high -risk population and suggests a potential clinical utility of PRS in differentiating between the risks of developing aggressive and nonaggressive disease in men of African ancestry.Patient summary: In this large genetic study in men of African ancestry, we discovered nine novel prostate cancer (PCa) risk variants. We also showed that a multiancestry polygenic risk score was effective in stratifying PCa risk, and was able to differentiate risk of aggressive and nonaggressive disease.& COPY; 2023 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Background:This study aimed to characterise epithelial cell adhesion molecule (EpCAM) expression patterns in colorectal carcinomas (CRC) from Nigerian patients, its association with E-cadherin and tumour characteristics, to forecast patient selection for anti-EpCAM therapy among whom no data existed previously.Methods:Tissue microarray blocks of formalin-fixed and paraffin-embedded CRC tissues, with their non-cancer margins of resection, were sectioned and stained with EpCAM and E-cadherin primary antibodies. Scoring for antibody staining was done semiquantitatively by combining staining proportion and intensity. The outcome was correlated with patient age, gender and tumour histological parameters with p ≤ 0.05 regarded as statistically significant.Results:Sixty-three carcinoma tissues had staining status for the two markers and were included in this study. Of these, 36 (57.1%) showed positive EpCAM expression (immunoscore ≥3) out of which 83% (30/36 positive cases) were overexpressed (combined immunoscore ≥4) while 12 (19%) tissues were positive for E-cadherin. Non-tumour margins of resection tissues showed less EpCAM positivity in 24% (6/25) of histospots. The difference in staining between tumour and non-tumour margin tissues with EpCAM was significant (p < 0.001). Also, EpCAM overexpression was significantly associated with reduced E-cadherin (p < 0.035) expression in tumour cells. Tumour extent within the gut wall was equal (50% each) for early and late pT stages among EpCAM overexpressing tumours but two-thirds (8/12) of cases expressing E-cadherin had later pT stage paradoxically, while distant metastasis was negligible among tumours bearing both markers. Also, tumours overexpressing EpCAM had significant association with tumour-associated lymphocytes (p < 0.02 each).Conclusion:CRC in this study preferentially overexpress EpCAM over E-cadherin whose strong cell-cell contact inhibitory role is weakened even when expressed, resulting in further local tumour spread. This, and the observed immune response, supports targeted therapy among eligible patients.