We have compared cytosol proteins from primary carcinomas of the breast,sampledfrom a group of patients both before and after a 1-2 week course of tamoxifen ther-apy.Hormone receptor status on the same tissue was used to identify potentially endo-crine responsive and non-reponsive tumors.The proteins prepared were separated by twodimensional electrophoresis on 12-18% polyacrylamide gradient gels.Each gel was runwith 100μg of protein,and a sensitive silver staining method used for visualisation.Protein patte...