Distinguishable DNA methylation defines disease susceptibility influenced by race and ethnicity

Abstract

© The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. The Creative Commons Public Domain Dedication waiver (http:// creat iveco mmons. org/ publi cdoma in/ zero/1. 0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. This editorial refers to: “Race/Ethnicity-Associated Blood DNA Methylation Differences Between Japanese and European American Women: An Exploratory Study”, by M-A Song et al., https:// doi. org/ 10. 1186/ s1314802101171-w. Ancestral differences exist between populations—and when it comes to the study of genetic and epigenetic variations, they are also misinterpreted. Instead of focussing on uniqueness among populations, many genetic consortiums look for commonalities between groups. In the contemporary age of genetics, the field is shifting towards providing insights of singularity based on ancestry, and none more relevant than the validation of biomarkers implicated with the progression of human disease. In actuality biomarkers of high specificity and sensitivity are a clinical requirement when providing pre-emptive therapy to those diagnosed of being at risk. The necessity of identifying unique traits remains underscored when considering disease stratification, which are often extrapolated from different ancestral populations. In this issue of Clinical Epigenetics, scientists in search of methylation indices have identified differences between Japanese and European American women that may be informative for disease progression (CLEP-D-21-00295 official citation). This exploratory study was a nested cohort comprising 60 women, 30 Japanese Americans and 30 European Americans, derived from the MultiEthnic Cohort (MEC) from the same region of Oahu, Hawaii. A population study, the MEC, was originally conceived to assess relationships between diet and cancer in the USA that involve five ancestral backgrounds in Hawaii and California, namely African Americans, Latinos, Japanese Americans, Native Hawaiians and European Americans [1]. The authors sampled this population of women because of the elevated risk of liver disease [2] and NAFLD-associated hepatocellular carcinoma among Asian Americans [3]. In this issue of Clinical Epigenetics, the authors hypothesize that DNA methylation could be a signature that distinguishes Japanese women from European Americans. They postulate that DNA methylation could represent physiological differences in liver function and pathological conditions that are often associated with lifestyle changes including socio-economic disparities. Japanese Americans had significantly higher blood CG methylation when compared to European Americans. The authors reported 174 differentially methylated CG sites with the majority (76%) of these hypermethylated in the Japanese Americans when compared to European counterparts. Differential methylation was predominantly found in the promoter regions of several genes implicated with liver function and disease such as tumour cell proliferation (AFAP1 and CSMD3) and cirrhosis (KIAA0748/TESPA1). The authors of the study found other differentially methylated CG regions in relation to gene expression changes associated with pathophysiological processes such as adipogenesis and insulin signalling (SOX6 and SH3BP4) and inflammation or fibrosis (MIP1B/CCL4). The authors hypothesize that Open Access