Fig. 4

Overlap of target genes in the miRNA subset. a Supervised absolute expression heat map for 16 canine miRNAs in CMEC vs. CMT exosomal RNA samples. Three biological replicates (CMEC1, CMEC2, and CMEC3) corresponding to normal mammary tissue exhibit relatively low levels of expression for the first eleven miRNAs while the last five miRNAs exhibit considerably higher levels of expression. The pattern is reversed in the mammary tumor samples (CMT12, CMT27, CMT28, CMT47, and CMT119) as visualized in the right side of the heat map. Because of the dichotomous pattern of expression across the control and mammary samples, these miRNAs may represent valuable candidates for clinically relevant biomarkers. b A miRNA subset was selected from among the 16 miRNAs (a). Overlap of target genes is indicated by both numbers of target genes and percentage of total genes (sum of each miRNA’s target gene set). Cfa-miR-18a represents an miRNA with relatively low expression in normal mammary tissue and higher expression in mammary tumor samples. Similarly, cfa-miR-19a also exhibits low expression in normal mammary samples and higher expression in mammary tumor samples. In contrast, cfa-miR-181a exhibits considerably higher expression in the normal mammary tissue compared to 18a and 19a. Additionally, 181a expression in mammary tumor samples is greater than any other miRNA among the 16 miRNAs represented in (a)