A few studies have demonstrated ethnic diversity in the overall DNA methylation levels. Methylation of leukocyte DNA levels are highest in Hispanics, lowest in Blacks, and of intermediate levels in Whites (Terry et al. 2008). Ethnic differences have also been observed in the overall methylation of tumor DNA. For example, methylation of the IGTBP-3 gene in malignant mesothelioma was higher in Japanese patients than patients from the USA (Tomii et al. 2006) and the TMS1/ASC gene is more methylated in prostate cancer cases than controls in White patients, but not in Black patients (Das et al. 2006).
