Previous studies using human tumor samples suggested several lines of evidence that a higher rate of TP53 mutation (Olivier et al. 2006), DNA copy-number gain or increasing PI3K/mTOR gene signature (Creighton et al. 2009), and activation of the growth factor signal pathway (Arpino et al. 2005) could be associated with loss of PR expression in ER-positive cancer. The gene discussed is PGR; the disease is neoplasm.