Methylation frequency of CpG sites and association between the ID4 methylation percentage. (A) Methylation frequency of CpG sites in the ID4 gene in NBM, MDS and MDS-AL. Filled circle and empty circle represent one methylated CpG site (CG) and unmethylated CpG site (TG), respectively. P < 0.001. (B) Association between the ID4 methylation percentage using bisulfite sequencing PCR and methylight. Using linear regression, we obtained a goodness of fit of r
2 = 0.7168. Using an exponential curve, the goodness of fit was r
2 = 0.8485. AL, acute leukemia; MDS, myelodysplastic syndrome; NBM, normal bone marrow; TSS, transcriptional start site.