DNA methylation status at promoters of miRNAs down-regulated in CLL. DNA methylation status of promoter regions associated with down-regulated miRNAs (n = 10) was examined in CLL samples (●; n = 70) and compared with peripheral blood CD19⁺ B cells (PB, ○) and tonsillar CD19⁺ B cells (TS, ) from healthy donors. The statistical analysis was done using the Wilcoxon test between CLL and PB or CLL and TS. *P < .05; **P < .001. For miR-181a2b2, the mean value of the CLL samples showed lower methylation compared with PB and TS samples because the majority of CLL samples had very low methylation levels, although some patients showed highly methylated promoters.