The coming of age of microRNA for B cell lymphomas

The human genome is made up of only approximately one-third of gene coding sequences. The remainder of non-coding sequences, the majority of the DNA code, are poorly understood, but it is now recognized that short portions are transcribed into RNA sequences with common structures sharing length and shape. They have the ability to regulate the expression of genes by binding and inhibiting the RNA coding for genes. These were named microRNA (miRNA). Over the last decade much has been learnt about miRNAs. They are fewer than 1000 in number for the human genome, but each influences a large number of genes and functional pathways, being important controlling influences in both normal function and disease. In the field of lymphoid malignancies we are entering a new era with greater understanding of the role miRNAs in normal B cell development and their disruption in B cell malignancies. This opens the door for both prognostic and diagnostic markers, as well as potential for novel therapies related to identification of the deranged pathways they control. This review outlines the current state of our knowledge of miRNA for B cell malignancies and while already of some clinical utility, there is still much to learn.