MMP9 and breast cancer: For instance, circHIPK3, a particularly abundant and upregulated circRNA in colorectal cancer cells, might sponge endogenous miR-7 to inhibit miR-7 activity and then increase FAK, IGF1R, EGFR, and YY1 expression to promote colorectal cancer growth and metastasis [24]; circ_0001361 acts as an oncogene in the invasion and metastasis of breast cancer by targeting the miR-491-5p/MMP9 axis [25]; circ-RanGAP1 overexpression is associated with a high TNM stage of gastric cancer; and the circ-RanGAP1 mediates the miR-877-3p/VEGFA axis to promote gastric cancer progression [26].