By comparing methylation patterns of blood from healthy individuals and chordoma patients we found 20 significantly differentially methylated genes; 15 hypermethylated in chordoma (for example RASSF1, KL, RARB, HIC1, and FMR1) and 5 hypomethylated (HSD17B4, BAZIA, STAT1, NEUROGL, and JUP). This evidence concerns the gene HSD17B4 and chordoma.