Differences in miRNA expression between MCL and SLL. (A) Unsupervised hierarchical clustering of MCL and SLL samples showed 2 separate clusters of SLL patients with each having unique miRNA profiles. (B) A 26-miRNA signature differentiates MCL from SLL, with 23 miRNAs including 2 polycistronic miRNA clusters, miR106b-25 (miR-106b and miR-25) and miR106a-363 (miR-363 and miR-20b) being significantly up-regulated in MCL compared with SLL.