With regard to breast cancer, a study performed in 2000 by Vasaturo et al. [68] showed that overexpression of RSU1 in MCF-7 breast cancer cells induced p21 activation and reduced cancer cell proliferation through inhibition of Cyclin-dependent kinase (CDK), proposing that RSU1 acts as a tumor suppressor. The gene discussed is RSU1; the disease is neoplasm.