Since the Rho small GTPases regulate many cellular processes, including cytoskeletal dynamics, cell motility, and cell polarity, which are essential for the metastatic potential of tumor cells (39, 40), and previous studies have proposed the potential of ROCK-targeted therapy for cancer metastasis (41), we used a selective ROCK inhibitor (GSK429286) as positive drug control in the metastasis-on-a chip screen. The gene discussed is RHO; the disease is cancer.