Beside oncogenic RAS mutations, we have recently shown that an increased activity of a wild type N-Ras is both necessary and sufficient to drive the formation and/or progression of one breast cancer subtype, the “basal-like” breast cancer (BLBC)3, which is a sub-group of breast cancer that usually does not express estrogen receptor-α (ER), progesterone receptor (PR), or HER2. This evidence concerns the gene PGR and breast cancer.