OPCML and chordoma: DMR identified in comparison of chordoma and NP were located in genes with known role in tumor biology, including TERT, BLM, CDH11, CDH4, DLC1, OPCML, HIF1A, YWHAQ, MGMT, TP63, MTOR, MUPCDH, RIPK4, EGFR or TBC1D16. Most of these DMRs are significantly more hypermethylated in chordoma I (Fig. 1e, Additional File 6).