The present invention provides gene expression profiles indicative of whether a patient afflicted with PR driven malignancies is likely to be responsive to treatment with a therapeutic compound that is an anti-progestin. By identifying such responsiveness, a treatment provider may determine in advance those patients who would benefit from such treatment, as well as identify alternative therapies for non- responders. Also, provided are methods of using gene expression profiles and assays for identifying the presence of a gene expression profile in a patient. Also, provided are gene expression signatures differentiating cells expressing a K388R progesterone receptor from a wild type progesterone receptor.
