Faruk, Mohammed

Abstract Background: Vitamin C has long been recognized for its plethora of immune system and anti-inflammatory properties. Various cancers have been identified to have similarities in epigenetic inflammatory components. Because rates of prostate cancer have exhibited significant disparities in Black men with increased incidence and mortality, an examination of the intersection of diet, inflammation, and cancer and chronic disease diagnoses necessitates researchers to consider vitamin C. This study utilized data collected from the Prostate Cancer Transatlantic Consortium (CaPTC) Familial Cohort Study, an ongoing longitudinal cohort study initiated in 2017 which explores risk factors of prostate cancer among African Black men in Nigeria, Cameroon, and the United States (U.S.). Aim: The aim of this study was to examine the consumption habits of vitamin C-rich foods in African Black men and determine if dietary patterns influenced risk of cancer diagnosis. Methodology: Descriptive analyses compared vitamin C-rich food consumption among the countries of Nigeria, Cameroon, and the U.S. Unadjusted logistic regression models were used to identify association of cancer diagnosis with consumption of vitamin C fruits and vegetables. Odds ratios and 95% confidence intervals were estimated. Results: From 803 unique participants included in this study, most resided in Nigeria (82.6%), were married (92.9%) with a median age of 50.7 years. Chi square tests revealed significant differences in dietary consumption of vitamin C-rich fruits and vegetables among the three countries. Men in Nigeria presented with the highest weekly fruit consumption (p < 0.001). Men in the U.S. exhibited the greatest weekly vegetable consumption (p < 0.001), while men in Cameroon showed the least weekly consumption of both fruits and vegetable (p < 0.001). Fourteen Cameroon and zero U.S. men reported a cancer diagnosis. Logistic regression models were significant only for Nigeria where age (p < 0.001), leafy vegetable (0.04), berries (p = 0.05), and citrus fruit consumption (p = 0.04) were identified to be significant predictors of increased risk of cancer diagnoses. Conclusion: Regular consumption of vitamin C rich foods assists with reduction of inflammatory components that may contribute to cancer genesis. Dietary consumption patterns of vitamin C rich fruits and vegetables show significant disparities in Nigeria, Cameroon and the U.S. with men in Cameroon reporting the least weekly consumption of both vitamin C-rich fruits and vegetables. Future investigation into revisiting these associations as well as including an assessment of access to quality nutrition in both cost and availability should be explored, as regular consumption of leafy vegetables, berries, and citrus fruit were found to significantly decrease risk of cancer diagnosis in this study. Citation Format: Jennifer M. Crook, Emeka Iweala, Ademola Popoola, Paul Jibrin, Mohammed Faruk, Anthonia Sowumi, Omolara Fatiregun, Nkegoum Blaise, Catherine Oladoyinbo, Ifeoma Okoye, Abdulkadir Ayo Salako, Abidemi Omonisi, Iya Eze Bassey, Kayode Adeniji, Nggada Haruna Asura, Ernest Kaninjing, Oluwole Kukoyi, Parisa Fathi, Ruth Enuka, Oluwaseyi Toye, CaPTC Investigators, Folakemi Odedina. Vitamin C prediction of cancer diagnosis in men of African ancestry in Nigeria, Cameroon, and the United States: An analysis of the CaPTC prostate cancer study [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C068.

In this study, we used whole-exome sequencing of a cohort of 45 advanced-stage, treatment-naïve Nigerian (NG) primary prostate cancer tumors and 11 unmatched nontumor tissues to compare genomic mutations with African American (AA) and European American (EA) The Cancer Genome Atlas (TCGA) prostate cancer. NG samples were collected from six sites in central and southwest Nigeria. After whole-exome sequencing, samples were processed using GATK best practices. BRCA1 (100%), BARD1 (45%), BRCA2 (27%), and PMS2(18%) had germline alterations in at least two NG nontumor samples. Across 111 germline variants, the AA cohort reflected a pattern [BRCA1 (68%), BARD1 (34%), BRCA2 (28%), and PMS2 (16%)] similar to NG samples. Of the most frequently mutated genes, BRCA1 showed a statistically (P ≤ 0.05) higher germline mutation frequency in men of African ancestry (MAA) and increasing variant frequency with increased African ancestry. Disaggregating gene-level mutation frequencies by variants revealed both ancestry-linked and NG-specific germline variant patterns. Driven by rs799917 (T>C), BRCA1 showed an increasing mutation frequency as African ancestry increased. BRCA2_rs11571831 was present only in MAA, and BRCA2_rs766173 was elevated in NG men. A total of 133 somatic variants were present in 26 prostate cancer–associated genes within the NG tumor cohort. BRCA2 (27%), APC (20%), ATM (20%), BRCA1 (13%), DNAJC6 (13%), EGFR (13%), MAD1L1 (13%), MLH1 (11%), and PMS2 (11%) showed mutation frequencies >10%. Compared with TCGA cohorts, NG tumors showed statistically significant elevated frequencies of BRCA2, APC, and BRCA1. The NG cohort variant pattern shared similarities (cosign similarities ≥0.734) with Catalogue of Somatic Mutations in Cancer signatures 5 and 6, and mutated genes showed significant (q < 0.001) gene ontology (GO) and functional enrichment in mismatch repair and non-homologous repair deficiency pathways. Here, we showed that mutations in DNA damage response genes were higher in NG prostate cancer samples and that a portion of those mutations correlate with African ancestry. Moreover, we identified variants of unknown significance that may contribute to population-specific routes of tumorigenesis and treatment. These results present the most comprehensive characterization of the NG prostate cancer exome to date and highlight the need to increase diversity of study populations. Significance: MAA have higher rates of prostate cancer incidence and mortality, however, are severely underrepresented in genomic studies. This is the first study utilizing whole-exome sequencing in NG men to identify West African ancestry-linked variant patterns that impact DNA damage repair pathways.

Abstract Men of African ancestry (MAA) have the highest global incidence and mortality of prostate cancer (PCa); however, the biology underlying this harsh disease presentation remains poorly understand, largely due to Africans and people within the African diaspora being under-represented in genomics research. MAA are younger at diagnosis, have higher tumor volume at diagnosis and have higher tumor aggression compared to European American men. Additionally, genomic profiling continues to show that PCa etiology and phenotype are influenced by higher amounts of African ancestry and that West African ancestry is associated with unique genomic alterations. Herein we utilize whole exome sequencing of a unique cohort of 45 advanced stage, treatment naïve Nigerian primary PCa tumors and 11 unmatched non-tumor tissue to compare genomic variants with African (AA) and European (EA) American TCGA PCa tumors. Nigerian samples were collected from 6 sites in central and southwest Nigeria. After whole exome sequencing, samples were processed using GATK best practices. Four genes [BRCA1 (100%), BARD1 (45%), BRCA2 (27%) and PMS2 (18%)] had germline variants in at least two Nigerian non-tumor samples. Across 111 germline variants, the AA cohort reflected a pattern [BRCA1 (68%), BARD1 (34%), BRCA2 (28%) and PMS2 (16%)] similar to Nigerian samples. Of the most frequently mutated genes, BRCA1 showed a statistically (p ≤ 0.05) higher mutation frequency in MAA. Disaggregating gene level mutation frequencies by variant revealed both ancestry linked and Nigerian specific germline variant patterns. Driven by rs799917, BRCA1 showed increasing mutation frequency as African admixture increased. BRCA2_rs11571831 was only present in MAA and BRCA2_rs766173 was increased in Nigerian men. 133 somatic variants were present in 26 PCa associated genes within the Nigerian tumor cohort. Nine genes [BRCA2 (27%), APC (20%), ATM (20%), BRCA1 (13%), DNAJC6 (13%), EGFR (13%), MAD1L1 (13%), MLH1 (11%) and PMS2 (11%)] showed mutation frequencies above 10%. Compared to TCGA cohorts, BRCA2, APC and BRCA1 showed statistically significant increases in Nigerian tumors. The Nigerian cohort variant pattern shared similarities (cosign similarities ≥ 0.734) with COSMIC signatures 5 and 6 and mutated genes showed significant (q < 0.001) GO and functional enrichment in mismatch repair and non-homologous repair deficiency (HRD) pathways. Here, we show that variants in DDR genes are increased in Nigerian PCa and that a portion of those variants correlate with increased African ancestry. Moreover, we identify variants of unknown significance that may contribute to population specific routes of tumorigenesis and treatment. These results present the most comprehensive characterization of the Nigerian PCa exome to date and further highlight the need to increase study population diversity. Citation Format: Jason A. White, Ernest Kaninjing, Kayode A. Adeniji, Paul Jibrin, John O. Obafunwa, Chidiebere N. Ogo, Mohammed Faruk, Solomon Rotimi, Ademola Popoola, Omolara A. Fatiregun, Olabode P. Oluwole, Balasubramanyam Karanam, Wei Tang, Stefan Ambs, Folake T. Odedina, Damali N. Martin, Clayton Yates. Tumor only analysis of whole exome sequencing from a multi-institutional Nigerian prostate cancer cohort reveals DNA repair genes associated with African ancestry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1507.