The purpose is to examine the original breast tumor material to see how much of a metabolizing enzyme (CYP3A4) is present in tumor material. The researchers want to see if this is in any way associated with how the patient responded to docetaxel. They also want to examine the genes in the tumor that are responsible for the production of CYP metabolizing enzymes, to see if they are normal or if they have polymorphisms, or change compared to 'normal' CYP metabolizing enzymes.