In vitro and in vivo experiments have demonstrated that VPA has the ability to inhibit growth and promote apoptosis in ovarian cancer cells and to alter the cell cycle in ovarian cancer cells, resulting in a decrease in the S phase, an increase in the G1 phase, an increase in the E calnexin expression, and a decrease in the metalloproteinase 9 (MMP9) expression [17]. This evidence concerns the gene MMP9 and ovarian cancer.