Exploring the genome-wide relation between copy number status and microRNA expression.

The deregulation of miRNAs has been associated with several different cancer types. Deregulation occurs in several ways, but generally little is known about the basis for the distorted expression of miRNAs. We investigated the relation between copy number status and miRNA expression at the genome-wide level using cytogenetic and array-based methods to characterize genomic aberrations in hematopoietic cell lines. For the same cell lines, we obtained global miRNA expression profiles, and analyzed the genome-wide correlation using the Spearman's rank test. This analysis showed that the expression of only a two miRNAs (miR-324-5p encoded by MIR324 at 17p13.1 and miR-660 encoded by MIR660 at Xp11.23) was influenced by copy number status. Our data imply that no direct relation between copy number status and miRNA expression exists in the investigated cell lines.