Sustained significant differential methylation between low and high ptgs2-expressing tumours was observed at loci COX2_cg07422329 (p < 0.001), COX2_cg08482694 (p = 0.036), COX2_cg16101346 (p < 0.001), COX2_cg18335243 (p = 0.028), COX2_cg24887140 (p = 0.003) and COX2_cg25147026 (p < 0.001). The gene discussed is PTGS2; the disease is neoplasm.