CD19 and acute lymphoblastic leukemia: To verify that the “top” 5139 differentially methylated CpG sites corresponded to a signature characteristic of B-ALL, independent from the different proportion of blood cells in the samples, we compared the CpG site methylation levels among the leukemic samples (S1, A1d, A2d, and A3d) and non-leukemic samples (S2, S3, A1r, A2r, and A3r) and the non-leukemic CD19+ B cells and CD34+ cells isolated from the adult donors and cord blood samples, respectively.