The authors performed microRNA and mRNA expression profiling of 90 lymphoblastoid cell lines and adopted correlation coefficient analysis to discover postive- or negative-correlation miRNA-mRNA pairs. For genes with significant correlation, they used TargetScan to check prediction, GO tool (http://discover.nci.nih.gov/gominer/) to check overpresented biological process genes and chromosomal location for the suspect that co-located genes and microRNAs tend to be correlated. They also pointed out the fact that miRNA mainly affects the protein level, which could be one of the reasons they did not observe any evidence of concordance in most miRNA sets.