The participation of the MMP9 axis was lately studied in association with miRNA and circRNA, where inhibition of MMP9 protein degradation by miRNA-516a promoted cancer metastasis, and MMP9 upregulation in circ0001361-overexpressed BC cells promoted cell migration and invasion (Chang et al. 2020; Liu et al. 2020). This evidence concerns the gene MMP9 and breast cancer.