Accumulation of miR-155 and BIC RNA in human B cell lymphomas

Proc Natl Acad Sci U S A. 2005 Mar 8;102(10):3627-32. doi: 10.1073/pnas.0500613102. Epub 2005 Feb 28.


We show that the microRNA miR-155 can be processed from sequences present in BIC RNA, a spliced and polyadenylated but non-protein-coding RNA that accumulates in lymphoma cells. The precursor of miR-155 is likely a transient spliced or unspliced nuclear BIC transcript rather than accumulated BIC RNA, which is primarily cytoplasmic. By using a sensitive and quantitative assay, we find that clinical isolates of several types of B cell lymphomas, including diffuse large B cell lymphoma (DLBCL), have 10- to 30-fold higher copy numbers of miR-155 than do normal circulating B cells. Similarly, the quantities of BIC RNA are elevated in lymphoma cells, but ratios of the amounts of the two RNAs are not constant, suggesting that the level of miR-155 is controlled by transcription and processing. Significantly higher levels of miR-155 are present in DLBCLs with an activated B cell phenotype than with the germinal center phenotype. Because patients with activated B cell-type DLBCL have a poorer clinical prognosis, quantification of this microRNA may be diagnostically useful.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Line, Tumor
  • Humans
  • Lymphoma, B-Cell / genetics*
  • Lymphoma, Large B-Cell, Diffuse / genetics*
  • MicroRNAs / analysis
  • MicroRNAs / metabolism*
  • RNA, Messenger / metabolism
  • RNA, Untranslated / analysis
  • RNA, Untranslated / metabolism*


  • MicroRNAs
  • RNA, Messenger
  • RNA, Untranslated