In several tumors (triple negative breast cancer, hepatocellular carcinoma, and glioblastoma), RND1 presents the features of a tumor suppressor gene i.e.,: (i) in breast tissue, its loss induces mammary tumorigenesis [10], (ii) its re-expression in tumor cells causes the cell to lose two cancerous properties (invasion/metastasis, proliferation) [10,45,46,47], (iii) its expression is down-regulated in tumors and is inversely correlated with the stage of the tumors [11,45]; and (iv) a weak expression of RND1 is correlated with a bad prognosis for the patients [10,45,46,47]. The gene discussed is RND1; the disease is neoplasm.