miRNAs are a group of small noncoding RNAs measuring 19-25 nucleotides. 
Sequence-specific binding of miRNAs to the 3´ untranslated regions of target 
genes leads to translational repressions. Dysregulation of miRNA expression 
involved in cancer can be triggered by multiple mechanisms including aberrant 
DNA methylation of the miRNA gene promoter. Of note, DNA methylation of tumor 
suppressor miRNAs has been implicated in various human cancers. Moreover, miRNA 
silencing mediated by aberrant promoter DNA methylation can potentially be 
reversed by hypomethylating agents, and hence may pose a new therapeutic target 
in cancer. In this review, the authors will focus on the aberrant methylation of 
miRNAs in the pathogenesis of lymphoid malignancies including chronic 
lymphocytic leukemia, multiple myeloma and acute lymphoblastic leukemia.