Ancillary Study of Methylation Biomarkers in a Randomized Controlled Trial of a Personalized Prevention of Colorectal Cancer

Based on the magnesium tolerance test (MTT, "gold standard" for assessing magnesium (Mg) status), it was found that over 50% of participants in the US exhibited Mg deficiency. Studies suggest that the relationship between high Mg intake and disease risks may be varied by an individual's Mg status. Despite its importance, MTT is not commonly employed in routine clinical practice or research studies. Instead, serum Mg levels are typically used for clinical diagnosis, although this method has shown limited efficacy in identifying Mg deficiency accurately. Consequently, there is a pressing need to develop practical, sensitive, and specific biomarkers that can efficiently identify individuals with Mg deficiency.

It is known that DNA methylation changes are inducible by environmental exposures, including nutrients, and reversible when the exposure disappears. There are two major types of DNA methylation modifications, 5-hydroxymethylcytosine (5-hmC) and 5-methylcytosine (5-mC). 5-mC is often associated with suppressed gene expression. 5-hmC, generated by the oxidation of 5-mC, is specifically enriched in expressed genes and play a critical role in activating and/or maintaining gene expression. We plan identify 5-hmC and 5-mC for Mg deficiency by a 4- phase comprehensive epigenome-wide association study (EWAS) using the samples collected in the "Personalized Prevention of Colorectal Cancer Trial [PPCCT, R01CA149633; PI, Dai & Yu]" .

The parent trial [NCT04196023] that supports this ancillary research is a randomized controlled trial to evaluate the efficacy of reducing the Ca:Mg ratio among those who consume high Ca:Mg ratio diets to decrease the risk of colorectal cancer. For this ancillary trial research, the investigators are examining ancillary measures of Changes of Cytosine Modification in TMPRSS2.