Considerable evidence points to the importance of disseminated tumor cells, which are commonly detected in the bone marrow and display features of cellular plasticity, in predicting the clinical outcome of breast cancer. In this issue of Cancer Discovery, Werner and colleagues report on the discovery of retinoic acid-induced 2 (RAI2) as a differentiation factor that suppresses early metastatic spread of estrogen receptor-positive breast cancer.
©2015 American Association for Cancer Research.