Integrative Epigenomic and Targeted Protein Analysis in MRONJ: Correlating DNA Methylation with Bone Biomarkers.

Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse effect of antiresorptive agents, including bisphosphonates (BPs) and denosumab (DMB). We conducted a case-control epigenome-wide association study (EWAS) of 24 cancer patients treated with BPs or BPs + DMB using the Infinium® MethylationEPIC v2.0 to explore epigenetic differences associated with MRONJ. Differentially methylated positions (DMPs) and regions (DMRs) were assessed across three analyses: MRONJ vs. controls (main), BPs-MRONJ vs. BPs-controls, and BPs/DMB-MRONJ vs. BPs/DMB-controls. Eight plasma bone biomarkers were quantified by Luminex and correlated with top methylation sites. We identified 10 DMPs and 4 DMRs at suggestive significance (p < 1 × 10-5). cg1913766 in the NOP56 promoter was hypomethylated in the main analysis (p = 2.19 × 10-7) and in BPs-MRONJ (p = 4.80 × 10-6), correlating with osteocalcin (p = 0.02 and 0.03, respectively). TNXB cg21289669 was hypermethylated in the main analyses (p = 6.31 × 10-6), and TNXB locus formed a DMR (p = 3.30 × 10-10) in the main and BPs-MRONJ analyses (p = 2.76 × 10-7). cg11392877 in PDE8A was hypomethylated in BPs/DMB-MRONJ (p = 5.35 × 10-7). TRIM15 was a significant DMR in BPs-MRONJ and the main analysis (p = 3.30 × 10-10). TRIM15, TNXB, and PDE8A regulate collagen I, while NOP56 supports ribosome biogenesis, potentially contributing to MRONJ. Given the small sample size, these findings are preliminary and validation in larger studies is warranted.