MMP9 and breast cancer: Antroquinonol has been reported to inhibit the migration and invasion of breast cancer cells, through suppression of matrix metalloproteinase-9 (MMP-9) and epithelial-mesenchymal transition (EMT) gene expressions [71], while antroquinonol Y (41) also exerts significant cytotoxic effects on human cancer cells (U251, HL60, SW480, and A549) without affecting normal cells (LO2) [63].