Correlation between microRNA expression on microarray and RQ-PCR. For a subset of microRNAs (miRNAs) and samples we performed RQ-PCR to independently assess miRNA expression. RQ-PCR data are normalized using let-7a and miR-16. There is generally good correlation between miRNA expression using the two techniques. probe-specific differences were observed, however. R value using Pearson correlation, P < 0.05 significant.