The LMO family genes consist of four members, LMO1-4, each of which has been established to be responsible not only for many normal developmental processes but also for the initiation and development of various human cancers, including T-cell acute lymphoblastic leukemia, neuroblastoma, lung cancer, colorectal cancer, and breast cancer [21, 22, 25, 30–32]. The gene discussed is LMO1; the disease is breast cancer.