GDF15 and neoplasm: Hypermethylation was associated with advanced tumor grade for BRCA1 (P = 0.003), CDH1 (P = 0.002), HSPA2 (P = 0.009), RASSF1A (P = 0.017), and THBS1 (P = 0.000), while methylated GDF15 (P = 0.002) promoter was associated with low tumor grade.