CD44, a transmembrane glycoprotein involved in cell adhesion, migration, differentiation, signal transduction and apoptosis 16, 17, has been proposed as a cancer stem cell (CSC) marker in several tumors 18-20, including PCa 21, in which also promotes cell migrations and invasion in vitro as well as metastatic dissemination in vivo and chemoresistance 21-23. The gene discussed is CD44; the disease is cancer.