MMP9 and cancer: To understand the mechanism by which Sox2 regulates the invasiveness of the RU cells, we examined if Sox2 modulates the expression of factors known to play key roles in regulating the invasiveness and/or EMT in various types of cancers, including Snail1, Slug, ZEB1, MMP2, MMP3, MMP9, Twist1, E-cadherin, N-cadherin, FAK and TGF-β[43-47].