Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jul 7;9(7):e18035.
doi: 10.1016/j.heliyon.2023.e18035. eCollection 2023 Jul.

Microbiome diversity in African American, European American, and Egyptian colorectal cancer patients

Amr Elkholy  1   2 , Nagavardhini Avuthu  3 , Mohammed Abdalla  2 , Michael Behring  1 , Prachi Bajpai  1 , Hyung-Gyoon Kim  1 , Doaa Header  4 , Reham Ah Abo Elwafa  5 , Hesham Saed  2 , Amira Embaby  2 , Nefertiti El-Nikhely  2 , Sarah Obuya  6 , Mostafa Mohamed  1   2 , Ahmed Ashour Badawy  7 , Ahmed Nawar  7 , Farrukh Afaq  1 , Laura Q Rogers  8   9 , Sejong Bae  8   9 , James M Shikany  8   9 , Lori Brand Bateman  8   9 , Mona Fouad  8   9 , Mansoor Saleh  10 , Temesgen Samuel  11 , Sooryanarayana Varambally  1   9 , Chittibabu Guda  3 , Waleed Arafat  7 , Upender Manne  1   9
Affiliations

Microbiome diversity in African American, European American, and Egyptian colorectal cancer patients

Amr Elkholy et al. Heliyon. .

Abstract

Purpose: Although there is an established role for microbiome dysbiosis in the pathobiology of colorectal cancer (CRC), CRC patients of various race/ethnicities demonstrate distinct clinical behaviors. Thus, we investigated microbiome dysbiosis in Egyptian, African American (AA), and European American (EA) CRC patients.

Patients and methods: CRCs and their corresponding normal tissues from Egyptian (n = 17) patients of the Alexandria University Hospital, Egypt, and tissues from AA (n = 18) and EA (n = 19) patients at the University of Alabama at Birmingham were collected. DNA was isolated from frozen tissues, and the microbiome composition was analyzed by 16S rRNA sequencing. Differential microbial abundance, diversity, and metabolic pathways were identified using linear discriminant analysis (LDA) effect size analyses. Additionally, we compared these profiles with our previously published microbiome data derived from Kenyan CRC patients.

Results: Differential microbiome analysis of CRCs across all racial/ethnic groups showed dysbiosis. There were high abundances of Herbaspirillum and Staphylococcus in CRCs of Egyptians, Leptotrichia in CRCs of AAs, Flexspiria and Streptococcus in CRCs of EAs, and Akkermansia muciniphila and Prevotella nigrescens in CRCs of Kenyans (LDA score >4, adj. p-value <0.05). Functional analyses showed distinct microbial metabolic pathways in CRCs compared to normal tissues within the racial/ethnic groups. Egyptian CRCs, compared to normal tissues, showed lower l-methionine biosynthesis and higher galactose degradation pathways.

Conclusions: Our findings showed altered mucosa-associated microbiome profiles of CRCs and their metabolic pathways across racial/ethnic groups. These findings provide a basis for future studies to link racial/ethnic microbiome differences with distinct clinical behaviors in CRC.

Keywords: African American; Colorectal cancer; Egyptian; European American; Microbiome.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
a: Stacked bar plots depicting the relative abundance of microbiota at the phylum level in each sample of CRCs and normal tissues of different racial/ethnic groups. b: Alpha diversity analysis of the microbiota of tumor (CRC) and normal samples of different racial/ethnic groups. Boxplot representing different alpha diversity indices of each group, (A) Shannon index, B) ACE index, C) Pielou's evenness index, and D) Chao1 index. ns indicates statistically non-significant differences within the alpha diversity indices between CRCs and normal samples (Wilcoxson signed-rank test, P > 0.05). c: Principal coordinate analysis (PCoA) based on weighted UniFrac distances of microbial communities in each race/ethnic group. Differences between tumor (CRC) and normal samples are shown in A) African Americans (p-value 0.12087), B) European American (p-value 0.64035), and C). Egyptians (p-value 0.83716). p-Values are from the adonis2 test of vegan package R.
Fig. 1
Fig. 1
a: Stacked bar plots depicting the relative abundance of microbiota at the phylum level in each sample of CRCs and normal tissues of different racial/ethnic groups. b: Alpha diversity analysis of the microbiota of tumor (CRC) and normal samples of different racial/ethnic groups. Boxplot representing different alpha diversity indices of each group, (A) Shannon index, B) ACE index, C) Pielou's evenness index, and D) Chao1 index. ns indicates statistically non-significant differences within the alpha diversity indices between CRCs and normal samples (Wilcoxson signed-rank test, P > 0.05). c: Principal coordinate analysis (PCoA) based on weighted UniFrac distances of microbial communities in each race/ethnic group. Differences between tumor (CRC) and normal samples are shown in A) African Americans (p-value 0.12087), B) European American (p-value 0.64035), and C). Egyptians (p-value 0.83716). p-Values are from the adonis2 test of vegan package R.
Fig. 2
Fig. 2
LEfSe analysis shows histograms of differential microbial taxa, at the species level, between tumor (CRC) and normal samples in each race/ethnic group. A) African Americans, B) European Americans, and C) Egyptians. Differential species with LDA score >2 at P < 0.05 are shown here.
Fig. 3
Fig. 3
LEfSe analysis shows histograms of differential microbial taxa between tumor (CRC) samples of different races at the species level. Differential species with LDA score >2 at P < 0.05 are shown here.
Fig. 4
Fig. 4
LEfSe analysis showing differential predicted metabolic pathways between tumors (CRC) and normal tissues in each racial/ethnic group. Differential pathways with LDA score (log10) >2 at P < 0.05 are shown in the histograms.
See this image and copyright information in PMC

References

    1. Ferlay J., et al. Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN 2012. Int. J. Cancer. 2015;136(5):E359–E386. - PubMed
    1. Carethers J.M. Racial and ethnic disparities in colorectal cancer incidence and mortality. Adv. Cancer Res. 2021;151:197–229. - PMC - PubMed
    1. Ibrahim A.S., et al. Cancer incidence in Egypt: results of the national population-based cancer registry program. J Cancer Epidemiol. 2014;2014 - PMC - PubMed
    1. Siegel R.L., et al. Colorectal cancer statistics, 2020. Ca - Cancer J. Clin. 2020;70(3):145–164. - PubMed
    1. Beaugerie L., Itzkowitz S.H. Cancers complicating inflammatory bowel disease. N. Engl. J. Med. 2015;372(15):1441–1452. - PubMed

LinkOut - more resources