In addition, the levels of proteolytic enzymes MMP2 and MMP9 are also evidenced to contribute to the invasion and metastasis of cancer cells [14], whereas the downregulation of these enzymes together with the inhibition of PI3K/AKT signaling pathway suppresses the migration and invasion of cancer cells in various cancers [14–16], including breast cancer [17]. The gene discussed is MMP9; the disease is breast cancer.