The mammalian DREAM complex has been studied principally in continuously growing cell lines derived from common cancers, exemplified by breast, lung, prostate, esophageal, and ovarian cancers and certain leukemias, in which the repressive form of DREAM has been disrupted, and/or in which misexpression of MYBL1 or MYBL2 results in them acting as oncogenes (38–45). The gene discussed is MYBL1; the disease is leukemia.