This is an investigational study. MK-0646 is not FDA-approved or commercially available. At this time, MK-0646 is only being used in research. Fulvestrant is currently FDA -approved and commercially available for the treatment of metastatic breast cancer in post-menopausal women. Dasatinib is FDA-approved and commercially available to treat chronic myeloid leukemia. At this time, the use of dasatinib in breast cancer patients is investigational.