CD5 and leukemia: We compared the methylation levels at the 4752 progression CpGs of the 27 paired leukemia samples in our study to that of six naive (CD5+ and normal) and six memory B cells (class switched and nonclass switched) using 450 k array data from the International Cancer Genome Consortium (ICGC).34 Using hierarchical clustering, we observed that in all patients the methylation status at these CpG loci were more similar to that of memory B cells than to that of naive B cells (Figure 4a).