Feasibility of circulating miRNA microarray analysis from archival plasma samples

MicroRNAs have been found to be deregulated in several diseases and, due to their high stability in body fluids, represent promising noninvasively detectable biomarkers. However, numerous technical variables can affect accurate measurement of circulating miRNAs. Using a microarray-based method we assessed the: (i) adequate intra- and inter-array reproducibility of miRNA profiling; (ii) feasibility of using archival plasma samples stored for an extended period of time and available in limited amounts; (iii) good correlation between different batches; and (iv) time-dependent increase of background signals close to the chip expiration date.