27 Prat Prat A A Cheang Cheang MC MC Martín Martín M M Parker Parker JS JS Carrasco Carrasco E E Caballero Caballero R R Prognostic significance of progesterone receptor-positive tumor cells within immunohistochemically defined luminal A breast cancer Prognostic significance of progesterone receptor-positive tumor cells within immunohistochemically defined luminal A breast cancer J Clin Oncol J Clin Oncol 2013 2013 31 31 203 203 209 209 10.1200/JCO.2012.43.4134 10.1200/JCO.2012.43.4134 23233704 23233704. This evidence concerns the gene PGR and breast cancer.