RHO and neoplasm: Indeed, it has been reported that tumor tissues were stiffer than normal mammary tissues in transgenic mice.3 Such an increase in substrate stiffness induced the disturbance of cytoskeletal tension and mechanotransduction that can trigger tumorigenesis and metastasis.39 A stiff substrate increases cytoskeletal tension by activating the Rho–ROCK pathway that induces the formation and stabilization of focal adhesion and activates focal adhesion kinase-mediated integrin signaling.