KEGG and GO analysis of the circRNAs/miRNAs/mRNA axis demonstrated that these networks are potentially involved in several biological processes in breast cancer: for example, (i) circCDC27 could be involved in ErbB signaling and apoptosis pathways (Supplementary Figure S5a) and (ii) circTADA2A-E6 could be involved in the PI3K-AKT, mTOR signaling pathway, ECM–receptor interaction, and apoptosis (Supplementary Figure S5b). Here, AKT1 is linked to breast cancer.