NR4A1 and breast cancer: Since Al-Hajj et al., (2003) revealed for the first time that the tumorigenic stem cells in breast cancer have the CD44+, the tumorigenic potential and invasive features of this phenotype have been confirmed repeatedly (Mylona et al., 2008; Abraham et al., 2005) Olsson et al., (2011), Sanchez et al., (2001), Found that there are no significant associations between the CD44 expression and tumor size, lymph node status and hormone receptor.