Differential expression of circulating exosomal miRNA among 6 paired nonmetastatic CRC and CRLM plasma specimens. (A) Volcano plot of the identified differentially expressed circulating exosomal miRNAs, with fold change > 2.0 and p-value < 0.05 considered significant; in the volcano plot, upexpression and downexpression miRNAs are colored in red and blue, respectively. (B) Hierarchical clustering of the 22 differential circulating exosomal miRNA expression from 6 patients with nonmetastatic CRC (in yellow) and 6 CRLM patients (in blue). Each row represents an individual miRNA, and each column represents an individual sample. The color shade indicates relative expression levels from low to high on a log2 scale from −2.0 to 2.0. CRC, colorectal cancer; CRLM, colorectal cancer liver metastases.