miRNA correlations between technical replication, biological replication and methodological replication. (A) Scatter plots of technical replicates in sample A. Illumina kit (ILMN), left panel (r = 0.978); Bioo Scientific kit (BS), middle panel (r = 0.984); and NEB kit, right panel (r = 0.994). (B) Scatter plots of sample A and sample B (left panel, r = 0.983); sample B and C (middle panel, r = 0.986), and sample A and C (right panel, r = 0.981). Only the plots for the pooled samples are shown. (C) Scatter plots of ILMN and BS (left panel, r = 0.889), ILMN and NEB (middle panel, r = 0.866), and BS and NEB (right panel, r = 0.898). Only the plots for the pooled samples are shown. (D) Heat map of unsupervised hierarchical clustering of the 100 most abundant miRNAs. Samples and library preparation methods are indicated on horizontal axis at the top of the heat map. miRNAs are indicated vertically on the right.