2. Patients must have previously received systemic standard care (or effective salvage chemotherapy regimens) for metastatic disease, if known to be effective for that disease, and have been either non-responders (progressive disease) or have recurred. Subjects with estrogen receptor-positive or progesterone receptor-positive breast cancer must have progressed on or not be a candidate for anti-estrogens or aromatase inhibitors and all breast cancer patients must have progressed on or not be a candidate for an anthracycline-containing regimen and a taxane-containing regimen.